awwa- water audit and leak detection guide (1992).pdf

8/17/2019 AWWA- Water Audit and Leak detection guide (1992).pdf

http://slidepdf.com/reader/full/awwa-water-audit-and-leak-detection-guide-1992pdf 1/164

Am erican W der Works Association

Caiifom b-Ne vada Section

of

Water Resources

The Resources Agency

water conservation

auidebook no. 5

Water

Audit

and

Leak Detection Guidebook



Copiesof thisGuidebook may be obtained

FREEf”:

Stateof California

Damimentof Water Resources

Bdetim &

Reports

P O Box 942836

. . - -.. - -. .

Sacramento,

CA

pQ236-0001

916)

653-1097

Other pblications availableFREE

f”

heDepartmentof Water Resources include:

Catalog ofw ate r ConservationMaten

LeakAudit Software and Users

Manual

Municipal

Leak Detection Program LossReduction - Research &Analysis, by Boyle

I & W C m r c i a l Drought Guidebook

for

Water U tilities

Cme S W s f &trial Water Conservation n the San Jose Area

Seto f

nine

ChecklistsofWater Conservation Ideasfor Businesses

IndustrialWater Conservation Referencesfor:

Engineering.August

1982

Beverage and Bottling

Elec~?cpMng

FoodProcessing

Laundries

P q e r andPackaging

TenilesandDyes

Guidebwkon Conservation-Oriented Water Rates

Urban

Drought

Guidebook

WaterPk” BenefitlCast Analysis Software

for

Water Management Planning

Proposed

Model WaterEfficientLandscape

Ordinance

Landscqpe Water Conservation Guidebook

Agricultural Drought Guidebook

AGWATEROsoftware

How t

Do A n In-School Education Program

Designing a Public Information Programfor Water Conservation

THE COVER

PHOTO

depicts how underground

leaks

canbe detected and located by

listening for

the sounds of

leakage on system contact points, such as hydrants, valves, and

meters.

This

memberof a leak detection crew is using sonic equipment to conduct an initial

listening survey.



State of Californ ia

The Resources Agency

Water Audit and Leak Detection Guidebook

Fifth in a Series

of

Water Conservation

Guidebooks for

U s e

by

nterested Organizations ,

Inc luding Water Agencies, Waste Water Treatment Agencies,

Government, and Service Grou ps

August 1986

(Revised June 1992)

of

Water Resourc es

r Conservation Office

American Water Works A ssoc iation

Californ ia-Nevada Section



FOREWORD

An effective way to conserve water is to detect and repair leaks in municipal water systems. This

con trols loss of water that water agencies have paid to obtain, treat, and pressurize. Because water

leaks from the system before it reaches the consum er, water agencies lose revenue and incur

unnecessary costs.

The Califomia Department of Water Resources

@WR

estimates that about

250,000

acre-feet of

water leaks from municipal systems in Califomia each year. DWR's experience in working with

60 ocal water agencies, whose water audits reveal leak detection projects

to

be cost effective,

indicates that leaking water can be controlled at a cost averaging less than $50per acre-foot, a cost

usually less than what a water agency pays fo r the water.

A w ater audit and leak detection program has benefits in addition to the value of w ater control.

Meter testing performed as a part of the water audit will frequently identify customer meters that

inaccurately recordwater use. Recalibrating inaccurate meters

will

result

in

increased revenues

to

the water agency. Early detection of leaks will reduce the chances that the leaks will cause major

property damage to the water agency or its customers. Better knowledge of the location

of

valves

and mains wll allow the water agency to react quickly when em ergencies dooccur.

The first tw o chapters of this Guidebook provide practical methods and sam ple forms for

conducting a water audit. The audit enables one to determine if a leak detection project would

be

cost effective. The third and fourth chapters include instructions for the most efficient way to

detect leaks.

This Guidebook is one of DWR's how to series on step-by-step ways

to

develop specific water

conservation programs. The inside of the front cover lists othe r DWR water conservation

publications. Water conservation assistance and training information can also be obtained from

DWR District Offices which are listed inside the back cover.

This Guidebook, which is jointly sponsored by DWR and the Califomia-Nevada Section,

American Water Works A ssociation (AWW A), reflects the wide participation, experience and

cooperation among AW WA mem bers and the Department.

David N. Kennedy, Director

Department of Water Resources

Michael J. hcG uire, Chairman

California-Nevada Section

American Water Works Association

iii



CONTENTS

FOREWORD

...............................................................

ACKNOWLEDGMENT .........................................................

O R G A N I Z A T I O N

...........................................................

INTRODUCTION ...........................................................

Purpose of

the

Guidebook ...............................................

B e n e f i t s

of

Water Audits and Leak Detection

D e f i n i t i o n o f a

Water

Audit

Cost

of

a Water Audit

..................................................

D e f i n i t i o n of

Leak

Detec t ion ...........................................

Cost of Leak Detect ion

.................................................

CHAPTER

1.

THE

WATER AUDI T

............................

............................................

Analyze

t h e

Value

of

Water Losses and Corrective Measures

Update t h e Water Audit Annually

..............

Eva lua t e Po ten t i a l Cor rec t ive Measures .................................

Per iod ica l ly Upda te the Master Plan

....................................

.......................................

CHAPTER

2. CONDUCTING

A

WATER

A U D I T

I n tr o du c ti o n t o the Water Audit Worksheet ..............................

Task

1:

Quan t i fy

the

Water Supply

.....................................

Step

1

. I d e n t i f y

A l l

Water Sources

..................................

Map Selection .....................................................

Plo t t i ng Loca t ions o f Sources

.....................................

Id en t i f y i ng Source Measuring Devices

..............................

Step 2

.

Qu ant i f y Water from Each Source .............................

Water Audit Study Period ..........................................

Units of Measurement

..............................................

T ot a l l in g Water Sources ...........................................

Step

3

. Ver i fy and Adjus t Source Quant i t ies .........................

Poss ib le Causes of Meter E r r o r ....................................

Meter

T e s t i n g A l t e r n a t i v e s

........................................

Adjus t ing Source Quan t i t i e s

.......................................Reservoir and Tank Storage Changes

................................

...

I l l

x i i i

x i v

1

1

1

2

2

3

3

5

5

5

5

6

7

a

13

13

13

13

13

14

14

14

15

15

16

17

18

18



CONTENTS

cont.)

Task 2: Quant ify Authorized Metered Water Use ......................... 19

Step 1

.

Identify Metered

Uses

....................................... 20

Step 2 . Quantify

Metered

Uses

.......................................

21

Meter Lag Corrections ....................................... 21

Step

3

.

Verify and Adjust Metered

Use

Quantities

....................

24

Sampling Residential Meters ....................................... 24

Calculating Total Sales Meter Error ............................... 25

Estimating Increased Revenue

......................................

29

Task

3:

Quanti fy Authorized

Unmetered

Uses

............................ 30

Step 1. Identify Authorized

Unmetered

Uses

..........................

30

Step

2.

Estimate Authorized Unmetered

Uses

.......................... 30

Task

4:

Quanti fy Water Losses ......................................... 40

Step 1

.

Identify Potential Water Losses

.............................

40

Step 2

.

Estimate Losses by Type of Loss

.............................

40

Task 5:

44

References ............................................................. 46

Analyze the Water Audit Results and Consider Corrective Measures

CHAPTER

3

. LEAK DETECTION

47

Visible

and Nonvisible Leaks ........................................... 47

Examples of Underground Leaks

..........................................

48

Value of Recoverable Leakage ........................................... 50

An Overview of Leak Detection Methods

..................................

51

Leaks

You

Can Expect t o Find

........................................... 53

Main Line Leaks ...................................................... 53

Service L i n e Leaks ................................................... 54

Residential

Meter Box

Leaks .......................................... 54

Residential Customer Leaks ........................................... 54

Valve Leaks .......................................................... 55

Miscellaneous Leaks

..................................................

55

v i



CONTENTS (cont.)

CHAPTER

4 . CONDUCTING

A

LEAK

DETECTION

SURVEY

Preparing for the Leak Detection Survey

................................

Pre-Survey Review ....................................................

Leak Detection Equipnent

.............................................

Selecting Team Members

...............................................

Planning the Survey ..................................................

Leak Detection and Repair Plan

.......................................

Team Training

........................................................

Equipment Tune-up

....................................................

Leak Detection Procedures ..............................................

Initial Listening Survey .............................................

Problems Encountered with the Listening Procedures

Relis tening t o Suspect Sounds ........................................

Pinpointing Leaks ....................................................

Ground Microphone Method ..........................................

Correlator Method

.................................................

Probe Method

......................................................

Excavating the Leak

...............................................

Leak Detection Tips ...............................................

Measuring and Estimating Losses from Discovered Leaks ..................

Calculating Leak Rates for Small Leaks .................................

...................

Determining Leak Detection Effectiveness

...............................

APPENDIXES

APPENDIX A SAMPLE

COMPLETED WATER

A U D I T REPORT AND

LEAK

DETECTION AND REPAIR

PLAN

.......................................

APPENDIX

B

TYPES OF METERS ............................................

APPENDIX C

RECOMMENDED

USES OF METERS BY CLASSIFICATION

...............

APPENDIX

D

METER SIZING PARAMETERS ....................................

APPENDIX E METER INSTALLATION CONSIDERATIONS

..........................

57

57

57

57

58

58

58

62

63

63

63

64

65

65

67

68

71

72

73

75

77

78

83

103

107

111

115

v i

i



CONTENTS (ant . )

APPENDIX

F

METER

TESTING I N

GENERAL ...................................

117

APPENDIX G

METER

TESTING WITH A PITOT ROD ............................. 119

APPENDIX

H LONG-TERM METER SURVEILLANCE

...............................

121

APPENDIX I CALCULATING

EVAPORATIVE WATER LOSS ......................... 123

APPENDIX

J

LEAK DETECTION

EQUIPMENT

...................................

125

APPENDIX

K

WATER A U D I T AND LEAK DETECTION BLANK FORMS ................. 127

EXAMPLES

Example

1

2

3

4

5

6

7

8

9

10

11

12

13

14

Water Audit Worksheet

.............................................

System Smnary of Water Source Measuring Devices ..................

Uncorrected Total Water Supply i n 1983

............................

Adjustments t o Source Tot al s Due t o Source

Meter

Error

............

Changes i n Reservoir Storage ......................................

Percent Water Consumption by Meter Size

...........................

Uncorrected Total Metered Water Use ...............................

Billing Cycles Related

to

Water

Audit Periods

Detailed

Meter

Lag Correction

.....................................

Adjusting Residential

Meter

Records for Sales Meter Error

Calculation of Residential Water

Meter

Error

......................

Meter Test Data for Large Meters ..................................

Calculation

of Meter

Error for Large Meters

.......................

Calculation

of Total Sales

Meter

Error

............................

.....................

.........

9

14

15

18

19

20

21

22

23

26

26

27

28

29

v i i



CONTENTS (cont.)

Example

15 Potential Revenues from Recalibrated Large

Meters

.................

16

17

Estimate of Water Volumes Used by Tank Trucks .....................

18 Estimate of Landscape Watering

....................................

19

Leak Detection and Repair Plan Worksheet

..........................

20 Leak Detection Survey Daily Log ...................................

21 Leak Repair Report

................................................

22 Leak Detection and Repair Project Sumnary

.........................

Calculation of Water Volume from Variable Rate Discharge

..........

ILLUSTRATIONS

1

Yearly Water Distribution

.........................................

2

Nonvisible Leak ...................................................

3

Doorhanger Notifying Residential Customer of

Possible Plumbing Leaks .........................................

4 How a Corr elator Works ............................................

TABLES

Table

Steps in a Water Audit ............................................

Weighting F ac to rs for Flow Rates Related t o Volume Percentages

Value of Recoverable Leakage ......................................

Leak Losses for Circular Holes Under Different Pressures ..........

Leak

Losses

for Joints and Cracks Under Different Pressures .......

Drips per Second

Converted

t o Gallons per Minute

....

..................

Cups per Minute Converted to Gallons per Minute ...................

i x

a

30

33

35

36

59

74

79

81

8

48

64

69

7

25

50

77

77

78

78



Photographs

Number

1

2

3

4

5

6

7

8

9

10

11

12

13

14

15

16

17

18

WATER AUDIT AND LEAK DETECTION GUIDEBOOK

Photographs

&

Illustrations

Caption

L i s t e n i n g

for the sounds of leakage.

How t o use a pitot rod for measuring flow i n a pipe.

Recording pitometers may be used t o measure flows

and cal ibr a te larg e

meters.

Correct meter installations include a small bypass meter,

a debris

screen,

and check valves on both si des of t he

meter.

Comnercial meters may be tested repaired and calibrated

on meter test bench.

Hydrant flushing programs improve water quality.

Records should be maintained of water used for

street

cleaning.

Cemeteries

may be l a rg e water use rs .

Decorative water f a c i l i t i e s

u s e

a lot of

water.

Meter readers

must

cope with different meter dials and

u n i t s of measurement.

Page

Cover

16

17

24

27

32

34

36

37

40

Water s to ra ge tank s may be subject t o overflow and leakage. 43

Visible l ea ks , l i k e t h i s f i r e hydrant, ar e ea si ly found. 47

47

The

flow 49

Nonvisible leaks usually occur underground.

Circumferential break

on

a

6

inch cast iron main.

r a t e was measured a t 98 gpm.

Valves are

excellent

contact points to

l is ten

for sounds

of leakage.

51

Excavating a 53 gpm leak on old steel main.

53

Service l a t e r a l le ak s a r e common i n metalic pipes. This 53

lea k was measured a t 2 gpm.

Meter box leak s a r e sometimes v is ib le . Here leak 54

detection equipment determines

i f

standing water

is

runoff or leakage.

X



Photographs (cont.)

Number Caption

Page

34 Uncovering leaks require8 carc excavation t o avoid, 72

35 Exercising

the

hydrant valve assists

i n

pinpointing 73

36

75

other pipes and/or

u t i l i t i e s .

the

leak.

Service

l i n e

leaks can be easily repaired by replacing

a portion of the service.

pipe i n l i n e

with

a

test meter

and measure the flowrate.

Sane agencies place the damaged

37

Plast i c services are a lso subject t o deteriora t ion

from

improper installation which results

i n

leaks.

76

x i

i



ACKNOWLEDGMENT

The Water Audi t and Leak Detect i on Gui debook

has

been prepared by t he

Cal i f orni a Depart ment of Wat er Resources' (DWR) Of f i ce of Wat er Conservat i on

under a State Assi st ance Grant f romthe St ate Wat er Resources Cont rol Board.

The grant was f unded f romt he Cl ean Water and Water Conservat i on Bond Law

passed by t he voters as Proposi t i on 2 i n 1978.

DWR acknow edges al l of t he publ i c water agenci es t hat par t i ci pat ed i n t he

st at ew de water audi t and l eak detect i on program These agenci es f i el d test ed

t hese procedures and provi ded comment s and suggest i ons t hat cont r i buted t o t he

i mprovement of t hi s Gui debook.

Addi t i onal t hanks are extended t o the many revi ewers and support ers of thi s

Gui debook through i t s devel opment . Speci al cont r i but ors i ncl ude: I an

Bal l ant i ne, Car l Buet t ner , J ohn Cur t i s, Al l en Dei t emann, Max Ew ngt on, Suzanne

Kane, Al an Kenf i el d, Wl l i am Ki ngst on, Gordon Laver t y, Paul McMann, J oseph

Romano, Donal d Vandekar and Dean Wheaden.

thei r t i me, pat i ence, suggest i ons,

and encouragement.

Water conservati on ef f ort s of DWR have been wel l supported by t he Ameri can

Water Works Associ ati on (AWWA) , part i cul ar l y by Davi d Todd, Chai rperson of t he

Cal i f orni a-Nevada Sect i on Water Conservat i on Comni t tee.

The aut hor s especi al l y appreci at e

AWWA' s Cal i f orni a-Nevada Sect i on endorses t he Water Audi t and Leak Detect i on

Gui debook and j oi ns

DWR

i n i t s publ i cat i on. Thanks go to:

Donal d Paf f Chai r man, AWA Revi ew Commt t ee

Lar r y Sear s Member, AWA Revi ew Comni t tee

Phi l l i p Ut i c Member , AWWA Revi ew Commt tee

Gordon Lavert y Chai rman- el ect Cal i f orni a- Nevada Sect i on

Ameri can Water Works Associ at i on

x i i i



STATE OF CALI FORNI A

Pete

Wilson, Governor

THE RESOURCES AGENCY

Douglas

P.

Wheeler, Secretary

for

Resources

DEPARTMENT OF WATER RESOURCES

David

N .

Kennedy, Director

J ohn J . Si l vei r a Rober t

G .

Potter

J ames U. McDani el

Deput y Di r ect or

Chi ef Deput y Di r ect or Deput y Di r ect or

L. Luci nda Chi pponer i Susan N. Weber

Assi st ant Di r ect or f or Legi sl at i on Chi ef Counsel

OFFI CE OF WATER CONSERVATI ON

J onas Mi nt on

...........................

Chi ef , Of f i ce of Wat er Conservat i on

Kei t h Wat k i ns ..................... Chi ef , Ur ban Wat er Conser vat i on Br anch

Thi s r epor t was wr i t t en by :

Chr i s t opher Car r

..............................

Of f i ce of Wat er Conservat i on

Char l i e P i ke ................................... Of f i ce of Wat er Conser vat i on

wi t h maj or ass i s t ance f r om

Edna Bai l ey .................................... Of f i ce o f Wat er Conservat i on

Pat t i Pal ac i os

................................

Of f i ce o f Wat er conservat i on

Lynda Her r en ................................... Of f i ce o f Wat er Conservat i on

Al i ce Br ooks ................................... Of f i ce of Wat er Conservat i on

Tr av i s L at ham

...........................................

Di vi s i on of Pl anni ng

Sus an Tat ayon ........................................... Di vi s i on of Pl anni ng

Ear l Bi ngham ............................................. Di vi s i on of Pl anni ng

xiv



SPECIAL NOTE

A l l photographs i n t h i s Guidebook were prepared by the staffs

of Cam unity Co nsu ltan ts, In c. and t h e Department of Water

Resources.

t h i s effort.

W grateful ly acknowledge their contributions to

X V



INTRODUCTION

Purpose of the Guidebook

This

Guidebook has been prepared t o

help

water agencies reduce water and

revenue losses.

detection surveys of piped, pressurized, potable water distribution systems and

provides:

I t includes techniques for conducting water audits and leak

step-by-step procedures f or conducting a comprehensive systemwide water

audit t o assess th e delivery efficiency of a water dis tri but ion system;

a worksheet and sample forms fo r each s tep of th e

water

audit;

spe cif ic techniques t o iden tif y, quantify, and ver ify a l l water sources,

uses, and losses;

a procedure and form t o cal cu la te increased revenues as a r e su l t of

te st in g and repair of l arg e meters;

alt ern ativ e actions t o correct ident ified problems i n a water system;

a t oo l t o determine whether a leak detection project would be cost

e f fec t ive ,

the

length of time

needed

t o perform a le ak dete ction survey,

and

what equipment is

needed.

step-by-step procedures fo r conducting a comprehensive leak de tecti on

project t o locate nonvisible underground leaks;

forms t o record information

from

surveying the distribution system,

pinpointing leaks, estimating leak losses, and documenting costs of survey

and repair; and

a procedure and

forms

to evaluate the cost effectiveness of the leak

detection project .

Benefits

of

Water

Audits

and

Leak

Detection

Reduced Water Losses

-

Conducting a leak detection project w i l l ident i fy

and locate water system leakage.

w i l l re su l t .

water

and reduced chemicals t o t r e a t water.

Financial Improvement - A water audit and leak detection project can

in cr ea se revenues from customers who have been undercharged, lower costs of

wholesale supplies, and reduce treatment and pumping costs.

Increased Knowledge of

the

Distribution System

- The

added familiarity of

the distribution system gained during a

water

audit and leak detection

pr oj ec t hel ps a u t i l i t y t o respond more quickly t o emergencies such as main

breaks.

Upon repair of

the

leaks, water savings

Savings are also realized in reduced power cos t s t o del iver

1



o More Ef f i ci ent Use of Exi st i ng Suppl i es

-

Reduci ng water l osses w l l hel p

st ret ch exi st i ng suppl i es to meet i ncreased needs. Thi s coul d hel p def er

the const ruct i on of new water f aci l i t i es, such as a new wel l , r eser voi r , or

t reat ment pl ant .

Reduced Pr oper t y Damage

-

I mproved mai ntenance of a water di st r i but i on

systemcan reduce t he l i kel i hood of proper t y damage and bet ter safeguard

publ i c heal t h and saf ety.

o

o

I mproved Publ i c Rel at i ons

-

The publ i c appreci at es geei ng that i t s water

syst ems ar e bei ng mai ntai ned.

detect i on tasks and doi ng repai r and mai nt enance work make a f avorabl e

i mpressi on.

Reduce Legal Li abi l i t y - Conduct i ng a water audi t and l eak det ecti on

proj ect provi des bet ter i nf ormat i on f or prot ect i on agai nst expensi ve

l awsui ts.

Fi el d teams carr yi ng out water audi t and l eak

o

Definition

of

a Water Audit

A water audi t i s a thorough examnat i on of t he accuracy of water agency records

and systemcont r ol equi pment . Wat er managers can use audi t s t o determ ne thei r

water di st r i but i on systemef f i ci ency. The overal l goal i s t o i dent i f y,

quant i f y, and ver i f y wat er and revenue l osses.

t o sel ect and i mpl ement programs t o reduce water and revenue l osses. Such

examnat i ons shoul d be perf ormed annual l y t o update t he r esul t s of ear l i er

audi t s.

Thi s al l ows t he water ut i l i t y

Cost of a Water Audit

The cost of a water audi t i s t he sumof i n- house work and f i el d work. Total

cost s depend on t he fol l ow ng var i abl es:

o t he si ze of t he servi ce area t o be audi ted

o

t he compl et eness and up- t o-date accuracy of t he water agency' s i n- house and

f i el d r ecor ds, i ncl udi ng meter t est i ng programs and records

o t he ext ent t o whi ch i n- house st af f or consul t ant s are

used

t o conduct

t he audi t

o var i at i ons i n cost s for i n- house staf f or consul t ant s to conduct al l or

a

port i on of t he audi t

Typi cal water audi t act i vi t i es i ncl ude:

o

o

master/ source meter t est i ng

o

ver i f yi ng, quant i f yi ng, and updat i ng: water source i nf l ow r ecords; metered

ver i f yi ng and updat i ng systemmaps

use r ecor ds, such

as

bi l l i ng and account i ng i nf ormati on; and unmetered use



r ecor ds, such as est i mates of wat er use for parks, c muni t y cent er s,

government f aci l i t i es, and f i ref i ght i ng

o

t est i ng resi dent i al , comer ci al , and i ndustr i al sal es met er s f or accuracy

i nspect i ng wat er measur i ng devi ces for proper si zi ng, i nst al l at i on, and

operat i on

\

o

o

f i el d checki ng di st r i but i on cont r ol s and systemoperat i ng procedures

Any of t he above act i vi t i es coul d be conducted by i n- house st af f or consul t ant s

or both.

The most expensi ve i tem f or

a

water audi t i s l ar ge meter test i ng.

meter test s r ange i n cost s f rom $150 t o $500.

$25 t o $50 each.

meters and sal es meters that must be tested to provi de current dat a f or t he

ent i r e system

Wat er agenci es par t i ci pat i ng i n t he St ate of Cal i f orni a' s water audi t and l eak

det ect i on grant program report ed cost s of water audi ts.

from $2,000 to over

$15,000

dependi ng on the accuracy of i nf ormati on al ready on

hand, t he compl exi t y of t he agency, and other var i abl es.

Large

Resi dent i al meter t est s average

The t ot al f i el d cost depends upon the number of sourcehast er

These cost s r anged

Definition of a Leak Detection

Leak det ect i on i s the syst emati c method of usi ng l i st eni ng equi pment to survey

t he di st r i but i on syst em i dent i f y l eak sounds,

and pi npoi nt t he exact l ocat i ons

of hi dden underground l eaks.

Cost of a Leak Detection

The cost s f or a l eak det ect i on proj ect i ncl ude cost s for l eak detect i on

equi pment and t he l eak detecti on cr ew to survey the system and cost s of

pi npoi nt i ng l eaks, est i mat i ng wat er l osses, and document at i on.

Leak repai r cost s ar e not consi dered a di rect cost.

cont i nual l y di scovered and repai red i n t he normal course of the ut i l i ty' s

oper at i ons, t he l eaks f ound dur i ng the l eak det ect i on program woul d event ual l y

be repai red at some t i me i n the f uture, somet i mes under emergency condi t i ons.

Cost s f or l eak det ect i on cr ews depend upon whether an agency uses i t s own

st af f , a consul t ant , or a combi nat i on of t he two. Leak det ect i on cost s are

normal l y expressed i n dol l ars per m l e of mai n surveyed.

cost s r ange f rom$75 t o

$300

per m l e of mai n. Cost s f or consul t ants r ange

from $250 per m l e of mai n t o $500 per m l e of mai n.

The var i abl es f or l eak det ect i on cost s i ncl ude wage rat es f or l eak detect i on

t eams, t he number

of

cont act poi nt s t o be sur veyed,

spaci ng of cont act poi nt s

t o be sur veyed, t ypes of mai ns and servi ces, accuracy of maps, and t he type of

l eaks t o be pi npoi nted.

Equi pment cost s ar e shown i n Appendi x

J.

Si nce l eaks ar e

I n Cal i f orni a, t hese

3



CHAPTER 1. THE WATER AUDIT

Water losses,

whether

due t o leakage,

thef t ,

underbilling of customers, or

faulty system controls, represent monetary losses to the water agency.

steps management can take to correct the unproductive elements in the water

supply system.

This

is

water th at the agency has already paid t o obtain , t r e a t , and pressurize.

However, because it i s l o s t ,

the water produces no revenue. Outlined

here

a r e

Analyze the Value

of

Water

Losses

and CorrectiveMeasures

Evaluations of co rr ec ti ve measures should

be

based on the cos ts , feas ib i l i ty ,

and savings t h a t re su lt . Once

the

water audit has been completed,

the agency

w i l l

have

suff ic ien t da ta to

determine

where

the

greatest water losses are

occurring.

pri ori t ies . In se t t ing pr io ri t ie s , th e manager

w i l l

a lso

wish

to incorporate

local constraints. These,

of

course,

ar e unique t o each agency and ther efore

ar e not specified.

Answers to the following questions

w i l l

indicate which corrective actions

should be carried out.

o Where are losses occurring within the system?

o How much water is l o s t

i n

each problem area identified?

o

What co rrec t ive measures ar e

needed

t o reduce

the

water

loss?

o

What

w i l l

be the cost of reducing

the

water loss?

o What savings and benefi t:co st r a t i os w i l l result from reducing the water

loss?

o

When can

the

corrective measures

be

implemented?

This information w i l l give

the

agency

the

data necessary to

set

Evaluate Potential Corrective Measures

Examples of co rr ec tiv e measures t o be evaluated are:

o Perform a leak detection survey and leak repair program.

o

Replace mains

with

his tor y of ser ious leaks.

o

Exercise

valves annually.

o Implement corrosion control procedures.

Update the Water Audit Annually

Once a water agency has conducted a comprehensive water audit, annual updates

provide dat a t o help managers decide how t o ad just p r i o r i t i e s and monitor

progress made on system maintenance.

ident i fy new areas of system losses t o estab lis h

new

annual maintenance goals.

Updating a water audit w i l l usually be

less

expensive than the original audit.

Equally important,

the

update can

5



Periodically Update the Master

Plan

The agency' s master pl an i s a val uabl e pl anni ng t ool whi ch can be used t o set

pr i or i t i es and schedul e cor rect i ve act i ons to mai nt ai n i t s wat er di st r i but i on

system

Managi ng

a

water di st r i but i on systemrequi r es cur rent i nf ormat i on on

t he systems del i very capaci t y, mai nt enance, and water qual i t y.

An

updated

master pl an i ncl udes t he f ol l ow ng i t ems associ at ed w t h water audi t and l eak

detect i on programs:

o probl em areas and areas of potent i al water savi ngs i dent i f i ed i n a water

audi t

an anal ysi s of water and cost savi ngs achi eved by corr ect i ve act i ons

a

f easi bi l i t y anal ysi s of cor r ect i ve act i ons based on cost and

organi zat i onal constrai nt s

an anal ysi s of i mproved water systemef f i ci enci es resul t i ng f rompast and

proposed corr ect i ve act i ons

o an anal ysi s of t he possi bi l i t y that greater syst emef f i ci enci es can def er

expansi on of t he del i very system

o

o

o

o proj ected water needs

o an i mpl ement at i on schedul e that i dent i f i es when speci f i c cor r ect i ve

act i ons w l l be taken

updated maps show ng physi cal r el at i onshi ps and char acteri st i cs of t he

system



YEARLY WATER DISTRIBUTION

Average Daily Use

Total Measured Miscellaneous

Inaccurate Meters

to City Customers

Jan Feb Mar Apr May June July Aug Sep

Oct

Nov Dec

1. Yearly waler distribu tion (courtesy of Communlty Consultant. Inc.)

Introduction to the Water Audit Worksheet

Example 1 , "Water

Audit

Worksheet," on page

9

i s used t o record the r e s u l t s

of t he step-by-step computations involved i n audi tin g a

water

delivery system.

In Chapter

2 ,

ins tru ctio ns direc tin g you t o enter information on cer tai n

l i nes of tine worksheet a r e emphasized by arrows i n th e margins.

The Water Audit Worksheet is presented here to simply fa mi li ar iz e you

with

t h e

computational process and the types

of

data you

w i l l

need.

system w i l l provide

actual

data for your own agency.

Appendix

A

on page

83

is a Sample Completed Water Audit Report and Leak

Detection and Repair Plan which includes a worksheet using data from the

examples in t h i s chapter.

The audit

of

your

a



EXAMPLE 1

WATER AUDIT WORKSHEET

For th e Water D is tr ic t: -

LINE

1

2

2A

28

2c

3

4

5

6

7

8

9

‘10

ITEM

Uncorrected Total Water Supply

t o th e Distr ibution System

(Total of Master

Meters)

Adjustments t o Total Water

Source

Meter

Error

(+

or

-1

Change

i n

Reservoir and Tank

Storage (+ or

-)

Other Contributions

or

Losses

(+

or

-1

TOTAL Adjustments to Total

Water Supply

(+

or -)

(Add

Lines 2A, 2B, and 2C.)

ADJUSTED TOTAL Water Supplied

t o th e Distr ibution System

(Add

Line

1

and

L i n e 3.)

Uncorrected Total Metered

Water

Use

Adjustments Due t o Meter

Reading Lag Time (+ or -)

Subtotal:

Metered

Deliveries

(Add Lines 5 and

6 . )

TOTAL

Sales

Meter

Error and

System Service

Meter

Errors

(+ or -)

CORRECTED TOTAL Metered

Water

Deliveries (Add

L i n e s

7

&

8.)

CORRECTED TOTAL

Unmetered

Water (Substract l ine 9 from

Line 4.)

Supply

WATER VOLUM E UNITS*

Total

Subtotal Cumulative

---

I I_

--

*

The

units of water iieasurement must

be

consistent throughout the worksheet.

Their

sel ect ion (e.g., acre-feet, mill ions of gallons, hundred cubic-feet)

is

l e f t

t o

the

user.

9



EXAMPLE

1 cont.)

WATER AUDIT WORK SHEET Page

2 of 4

LINE

11

11A

11B

11c

1ID

11E

1IF

11G

11H

111

11J

11K

11L

11M

12

ITEM WATER VOLUME UNITS

Total

Subtotal Cumulative

~

Authorized Unmetered Water Uses

Firefighting &

Firefighting Training I

Main Flushing

Storm Drain Flushing

--

Sewer Cleaning

-

Street Cleaning

Schools

Landscaping

I n

Large Public Areas

Parks

Golf

Courses

Cemeteries

-

Playgrounds

Highway Median S tr ips

Other Landscaping -

Decorative Water Facilities

Swimming Pools

Construction Sites

Water Quality and Other

Testing (pressure testing

pipe, water quality, etc.)

-

Process Water a t Treatment

Plants -

Other Unmetered

Uses

TOTAL Authorized Unmetered

Water (Add Lines

11A

through

1 M. )



EXAMPLE 1 cont.)

LINE ITEM WATER VOLUM E

WATER AUDIT WORKSHEET

13

14

14A

14B

1 4 C

14D

14E

14F

14G

14H

15

16

17

18

18A

18B

19

Total

Subtotal Cumulative

TOTAL

Water Losses

(Substract

L i n e

12 from

Line 10.)

Identified Water Losses

Accounting Procedure Errors I

Illegal Connections

System Controls

Reservoir Seepage and

Evaporation

Malfunctioning Distribution

_ _

Leakage

_ _

Reservoir Overflow

_ _ _

Discovered Leaks

Theft __

TOTAL Identified Water Losses

(Add Lines 14A through 14H.)

Potential Water System

Leakage (Subtract

L i n e 15

from L i n e 13.)

Recoverable Leakage

(Multiply Line 16 by 0.75.)

page 3 of 4

UNITS

I _

_

_I

Cost Savings

Dollars per Unit of Volume

-

Cost of Water Supply

-_-----

Variable 0 &

M

Costs

$---.---

TOTAL

Costs P e r Unit of

Recoverable Leakage

(Add

Line

18A t o Line 18B.) $-----I

1 1



EXAMPLE

1

cont.)

LINE ITEM

WATER AUDIT WORK SHEE T

20 One-Year Benefit fran

Recoverable Leakage (Multiply

L i n e 17 by

L i n e

19.)

Leakage

TOTAL

COSTS

of

Leak Detection Project

(Divide L i n e

21

by

L i n e 22.)

21 TOTAL BENEFITS from Recoverable

(Multiply Line 20 by 2 . )

22

23

Benefit to

Cost

Ratio

Prepared by:

Dollars per

Year

$

Page 4 of

4

-

Name Date

T i t l e



Task 1. Quantify the Water Supply

Thi s part

of

t he water audi t i dent i f i es, quant i f i es, and ver i f i es t he water

suppl i ed t o the di st r i but i on system

Step

1.

Identify An Water Sources

I dent i f y and l i st al l water sources that suppl y t he di st r i but i on syst em

i ncl udi ng i nt er connect i ons w t h other systems and i ntermt t ent sour ces or

emergency suppl i es.

Map Sel ect i on.

the ent i r e del i very system

l egi bl e and easy t o work w th (a scal e of

1

i nch to

400

f eet i s suggested) .

none i s avai l abl e, t he next choi ces are aer i al photos or

a

regi onal ( ci ty or

county) map, w t h a t ransparent over l ay on whi ch the di st r i but i on mai ns can be

drawn. An al t ernat i ve woul d be t o draw a map t hat meet s your purpose.

Choose a symbol t o represent each t ype of water source:

wel l s; sur f ace di ver si ons such as l akes, st r eams, r eser voi r s; i nt er connect i ons;

and emergency sources.

Sel ect an exi st i ng map that shows t he pr i nci pal mai ns of

The best map f or t he pur pose i s one t hat i s

I f

aqueduct t ur nout s;

Pl ot t i ng Locat i ons of Sources.

di st r i but i on syst emmap.

I dent i f y and pl ot each water source on a

I dent i f yi ng Sour ce Measur i ng Devi ces.

gather dat a t o const r uct a t abl e ( see Exampl e

2)

t hat sumnar i zes i nf ormat i on

about t he measur i ng devi ce at each sour ce (such as meters, Parshal l f l umes,

wei r s, and st r eamgauges).

Vi si t each sour ce l ocat i on and

13



EXAMPLE 2

SYSTEM SUMMARY OF WATER SOURC E MEASURING DEV ICES

Sour ce 1

I I I

Sour ce

2

Sour ce 3

Type of Measuri ng Devi ce

I dent i f i cat i on Number

(may be ser i al no. )

Fr equency of Readi ng

Type of Recordi ng Regi st er

Uni t s Regi st er s I ndi cat e

Mul t i pl i er (i f any)

Dat e of I nstal l at i on

Si ze of Condui t

Fr equency of Test i ng

Dat e

of

Lat est Cal i brat i on

Ventur i

00002’78-A

Dai l y

Di al

100,000

gal l ons

1 .o

1950

24

i nches

Annual

4/ 1/ 84

Propel l er

8759

Weekl y

Di al

gal l ons

1o

1968

8

i nches

2 years

8/21/ 84

Ventur i

OC - 16

Dai l y

Wi l der Type M

cubi c- f eet

100.0

1955

11.5 i nches

4 mont hs

1

/ 15/ 85

Step 2. Qua ntify Water from Each Source

Water Audi t Study Peri od. Choose a

per i od that i s l ong enough t o anal yze and eval uate t otal systemwat er use.

12- month study per i od st art i ng i n J anuary and goi ng through December

i s

recommended.

year.

I t i s r ecommended that a cal endar year ( J anuary t hrough December) be used i n

order to reduce t he ef f ect s of any meter readi ng l ag t i me.

page 23. )

Sel ect a water audi t st udy per i od.

A

Most water systemr ecor ds are kept by ei t her cal endar

or

f i scal

Ei t her syst emnormal l y makes

12

mont hs of data avai l abl e f or revi ew

( See Exampl e

8 on

Uni t s of Measurement . Choose the measurement uni t s f or t he audi t . Most

water ut i l i t i es record total f l ow measurements i n mul t i pl es of acr e- f eet ,

cubi c- f eet , or gal l ons.

t he audi t .

Not e t he t ype of regi st er used f or each devi ce and ver i f y t he appropr i at e

conversi on f actor t o be

used

when readi ng t he devi ce.

The same measurement uni t s shoul d be used t hroughout



To tall in Water Sources. Each

meter

normally has some

t y p e

of to ta l l ing

d F V i E e ~ i X € G T . ~ i s t e r san be one

of

two types. Round-reading r eg i s t e r s

have a

series of

small

d i a l s

(pointers) on

t he

regis ter face, regis ter ing a

volume of water

i n

u n i t s , IOs, I O O S , 1,000s and 10,000s of cu bic- fee t or

gallons.

direct-reading dial that shows total units of volume.

Direct-reading re gi st er s have one la rg e

sweep

hand for testing and a

Month

Total

the

amount of water produced from each source

by

month and for the

entire

period as shown

i n

Example 3 (below).

Source 81 Source 112 Source 83

Turnout

Well

Fi eld Ci ty Monthly

W41 Intert ie Totals

acre-feet acre-f eet acre-feet acre-feet

Calcula te th e t o t a l for a l l your water sources during th e audit period and

enter the amount on

L i n e

1

of

the

Water Audit Worksheet.

Step 3. Verify and A djust Source Quantities

The amount of water

supplied t o a water system must be accurately quantified.

Although most product ion sources a re measured by meters,

used, such a s Par shal l

flumes

or weirs. Measurement errors provide incorrect

other devices ar e als o

data.

flow data w i l l inVaTiTii"Fthe e nt ir e y a z t= audit.

Such errors must

be

discovered and corrected because incorrect source

I____ _

~

_ _ _ _ _ - - _ -

-

- - - - - ---- ---- -

rrows

i n

the margin indicate information that is t o be entered on the

water

audit worksheet.



Review

available

meter test

results for accuracy

w i t h i n

applicable American

Water Works Association

(AWWA)

standards.

standards for i t s category, repair and recalibrate it t o function within

acceptable l i m i t s .

If

no

meter test

resul ts are avai lable ,

test the meter.

Possible Causes of

Meter

Error.

causes other than normal wear.

each production measuring device.

If t he

meter

error exceeds

the

Inaccurate source meters can result

from

Review

th e dis tr ib ut io n system map loc at ion of

Then

inspect each source

meter

in the

f ie ld. Make

the

following checks and act accordingly.

o

Determine

whether the

proper types of meters

were selected

for use.

o

Determine whether

meters

of the proper size were selected for use.

th is agains t

the

manufacturers' recomnended ranges.

o

Determine whether meters were instal led correct ly.

o Determine whether

proper registers were

selected

and installed

correct ly.

o Determine

by inspection

whether

hard-water encrustation

is

present.

o Determine

whether the meter is level .

slope or vertical operation.

Check

Meters ar e usually not designed f or

o

Have an employee other than

the

regular

meter

reader make a special

meter

reading of the master

meters,

or

send

another employee t o accompany the

2.

HOW

to u s e a

pnot rod

for

measuring f low In

a

pipe.

16



meter reader t o verify the sample readings.

whether

the

reg is te r is being misread and recorded improperly and

the

conversion fa ct or s a r e being improperly used.

p i t m e t e r .

A

partial blockage to

the

throat of t h e meter might

be

present.

adequate for non-turbulent flows.

The

device should

be

tested

a t d i f fe ren t

flow ranges.

If

t h e pressure deflection for appropriate flows is adjusted

without checking th e ven tur i i t se l f , then the meter can s t i l l

be

recording

flows erroneously,

The purpose is t o determine

o

The primary device on a l l ven tu ri meters should be tes ted with a pinpoint

Testing

the

meter

with

a pitometer w i l l determine

i f the

ins ta l la t ion

is

Meter Testing Alternatives.

tested within the l a s t 12 months.

which are

i n

order of effectiveness.

1 . Test the

meter

in place. Retro fi t t in g piping

may

be required.

2.

Test a l l measuring devices t ha t have not been

Choose from among t h e following options

Compare

the

meter

reading

with

readings

of

a calibrated

meter

ins ta l led in

series with the original

meter.

Record meter readings fo r a given flow over a speci fi ed time period.

Remove

the meter

and replace

it with

a calibrated

meter;

record

t h e

readings from the calibrated meter for the same flow over the same period;

compare the readings.

Test

the meter a t a

meter

t e s t i ng fac i l i t y .

3.

4.

Meters can be

tested

either

i n

a

meter

shop or

i n

the f i e l d

w i t h

a variety of

portable equipment.

free by electric u t i l i t i e s ) c a n

be

used to check meters and is provided by

some

e l e c tr i c u t i l i t i e s .

laboratories ar e a lso avai lable.

pitotmeter and

the

r e su l t s may be off by a s much a s 10 percent.

single point pitotmeter mus t

be

used for accurate results.

Pump efficiency

flow

t e s t i ng

(sometimes

provided for

Consultants, meter manufacturers, and spe cia l te st in g

Some el ect r i c ut i l i t i e s use an averaging

A standard

3.

Recordlng pltometers may be used to measure

f lows

end calibrate large

meters.

17



Adjusting Source Quantities.

Master meters can either over or under register.

t ha t

i s

inaccurate, adjust the figures t o reflect the variance by calculating

the corrected metered volume ( C M V ) . To calculate the

CMV,

divide the

uncorrected metered volume (UMV) by the measured accuracy of the meter and

subtract

the

UMV

a s shown i n Example

4.

Adjust source data for

meter

inaccuracies.

When you f ind a

master

meter

~~

~ -p:ed

Source Volume

I.D.

EXAMPLE

4

ADJUSTMENTS TO SOURC E TOTALS DUE TO SOUR CE METER ERROR

Percent

Meter Error Calcula tion Corrected

Meter

Error (ME) Meter Metered

Accuracy ME

= UMV - UMV Error Volume

(MA)

O X M A

(ME) (CMV)

Source 1 has a meter accuracy of 95 percent which means that it is under

measuring by 5 percent.

means that it is over measuring by 3 percent.

the

UMV by the measured accuracy of t h e

meter

and subtracting

the UMV.

Source 3 has a meter accuracy of 103 percent

which

Calculate the CMV by dividing

1

6,165 95 (6,165)/0.95)

-

6,165 324.5 6 89.5

2

2,700

100

(2,700)/1

OO

-

2,700

+

00.0

2,700

3 2, 05 103 (2,405)/1.03)

-

2,405

-

70.0 2,335.0

TOTAL ADJUSTMENTS to Source

Meter

Readings Due t o Meter Error R54.5

acre-feet

E n t e r Source Meter Error on

L i n e

2A of t h e Water Audit Worksheet. .C

Reservoir and Tank Storage Changes.

source meters are uostream

from

the s torage fac i l i t i e s .

Remember

that water

These changes must

be

considered

i f t he

flowing out of r e s e h o i r s and tanks adds

t o

th e supply measured in to the

system. If the re se rv oi rs have more water a t th e end

of

the audit period than

a t the beginning,

then the

increased storage was measured by the source meters

but not consumed by the customers.

subtracted from

the metered

supply.

storage,

then

the decreased amount of stored water should

be

added t o th e

metered

supply.

Such increases i n storage should

be

Conversely,

i f there is

a

n e t

reduction

i n



Reservoi r

nter t he Changes i n Reservoi r and Tank St orage on l i ne 2B of t he Water Audi t

r some water syst ems, t here may be addi t i onal cont r i but i ons or l osses t o the

ot al suppl y.

t ers the water syst embet ween t he mast er source meter and t he f i ni shed water

em such as i nf i l t r at i on i nt o an open channel or l osses f roman unl i ned or

en channel .

ese addi t i ons or l osses shoul d be account ed f or as ot her cont r i but i ons and

osses.

orksheet.

dd t he Source Meter Err or , Changes i n Reservoi r and Tank St orage, and Ot her

ont r i but i ons or Losses t o the wat er suppl y.

he Water Audi t Worksheet.

dd Tot al Adj ust ment s to Tot al Water Suppl y (Li ne

3)

t o Uncor rect ed Tot al Water

uppl y ( Li ne 1) to get Adj ust ed Total Wat er Suppl i ed to t he Di st r i but i on

orksheet.

-c

For exampl e, t here may be an addi t i onal sour ce of suppl y that

Enter Ot her

Cont r i but i ons or Losses on Li ne 2C of t he Wat er Audi t

c

Enter t he r esul t on Li ne 3 of

Enter t hi s on Li ne 4 of t he Water Audi t Worksheet .

4

Start End

Change i n

Vol ume i n Vol ume i n

Vol ume i n

Gal l ons Gal l ons

Gal l ons

Task 2. Quantify Authorized Metered Water

Use

ut hori zed wat er i s water used f or benef i ci al purposes.

et ered del i ver i es, whi ch ar e normal l y sol d t o cust omers ( i ndust r i al ,

mner ci al , r esi dent i al , agr i cul t ur al , and ot her ) ; and

(2)

unmet ered

el i ver i es, f requent l y used f or publ i c purposes.

etered.

er i od sel ected f or quant i f yi ng water f romt he sources.

I t consi sts

of

1)

Al l unmetered uses shoul d be

When car ryi ng out t he f ol l ow ng st eps, be sure t o use t he same t i me



Step 1. Identify Metered Uses

You a r e now ready t o ide nti fy

metered

uses of water.

as

used

for

quantifying water

from the

sources.

o Ident i fy a l l users of water that are supposed t o have meters.

Use

the

same time period

Accounts can

be

iden t i f i ed by meter s e r i a l number, connection number, ass es so r' s parcel

number, street address, account number, or some ot he r system. Assign each

account t o a meter reading route.

Be

sur e t o include water provided t o other

agencies.

o Prepare meter lists by id en t if ic at io n number and si z e of meter fo r a l l a c t ive

accounts. Sort by type of use, including in du st ri al , commercial,

residential, agricultural, wholesale transfers, and others. The type of

metered

use is important because

i t

can help identify accounts that

represent la rg er volumes of s al es and grea ter p ote nti al revenue earnings, as

shown in Example

6.

Be sur e t o include a l l accounts for which metered use data

i s

available, even

i f

the account is not bi l led .

errors,

improper computer programing,

meter

misreading or other errors..

Unauthorized water use may a l so be occurring.

be checked.

Consider th e po ss ib il it y of accounting procedure

These improprieties should a l l

Please see Task 4, Quanti fy Water Losses (page 4 0 ) fo r methods t o estimate

these and other situations where metered use data is unavailable and potential

water los ses a re possible.

EXAMPLE 6

PERCENT WATER CONSUMPTION BY METER SIZE

>leter Si ze

(in)

Number of

Meters

Percent of

Metered

Consumption

518

314

1

1-1/2

2

3

4

6

11,480

10

338

124

216

15

7

6

70.1

0.1

4.4

2.8

11.7

6.4

2.0

2.5

100.00OTAL

12,196



Residential

Month acre-feet

Jan.

Feb

.

Mar.

April

May

June

July

Aug

.

Sept.

Oct.

Nov

.

D e c

.

Subtotal

Metered

Industrial Comnercial

Agriculture Subtotal

acre-feet acre-feet

acre-feet acre-feet

450

500

500

550

650

700

800

815

700

500

500

-50

7,115

110

110

110

120

130

150

150

150

140

110

110

110

1,500

-

TOTAL Uncorrected Metered Water

25

25

25

25

25

25

25

25

25

25

25

25

300

-

Use

-0-

-0-

-0-

75

175

230

175

230

200

0

-0-

-0-

1,085

-

585

635

635

770

980

1,105

1,150

1.220

1 o65

635

635

-

85

10,000

10,000

Meter Lag Corrections

Corrections must be made t o

water

sales data when t he beginning and ending

dates for the water audit (t h e source meter reading dates and

customer meter

reading dates) do not coincide.

The

January

1

t o December

31

period,

when

l i t t l e outside watering occurs,

is recamended since i t

minimizes water use

variances caused by sumner landscape watering.

An example of

the

comnon situation is shown i n Example 8 below.

example, the water audit is conducted for the calendar year, the source

meters

are read monthly on the

f i r s t

day of each month, and the customers' meters a re

a l l r e ad on the tenth day of the month.

bimonthly billing cycles.)

supplied and consumed for exactly the same time period.

In the

(The same methods a re app licable t o

The goal is t o c a lcu la t e

the

amount of water

2 1



EXAMPLE 8

BILLING CYCLES RELATED TO WATER AUDIT PERIODS

D e c .

Jan. Feb. Mar. Apr. May Jun. J u l . Aug. Sept. Oc t . Nov. Dec. Jan.

I I

I_

Water Audit Period January

1

t o December

31

X

x x x x x x x x x x x x

Source

meters

read on the

f irst

of each month

Customer meters read on the tenth day of each month

I n th e above situ at io n, no correction

is

made fo r t he water supplied

through the source

meters

since their reading

occurs on

the same day as the

audit begins and ends.

(January

I ) ,

then the water supplied for January 1 should be subtracted from

the to ta l water

u s e

read.

The customer meter readings ar e read on th e tent h of the month and do not

coincide with the audit period.

The best way to account for changing numbers of customers and changing

water

use patterns

i s

t o p ro ra t e the water use fo r t he f i r s t and l a s t bi l l i ng periods

appl ied t o the water audit .

The f i rs t bill ing period has only t e n days that actuall y occur i n the aud it

period.

Yet

the bil l ing information represents

31

days

of

water

use. If

s a l e s

for that December

11

through January 10 period a re 101.9 acr e-f eet, t he

amount ap pli cab le t o th e au di t period

is:

If

t he l a s t reading (December

31)

was a day l a t e

Therefore, a correction must be made.

101.9 acre feet x

I

o d a y s = 32.87 acre-feet

31 days

Thus only 32.87 acre-feet of the use read on January 10th applie s t o th e

audit period.

Completing the calculations, the re are 21 days a t t h e end on

the

audit period

th at ar e not included i n the billing data collected on December

10. Use for

the last 21 days i n December is obtained from the following January billing,

112.5 acre-feet. The amount appli cable t o t h e au di t period is:

112.5 acre feet x 21 days = 76.20 acre-feet

31 days

Thus 76.20 acre-feet is added t o t he use read on December 10th.

Customer meters a r e seldom a l l read on t he same day.

t o d i f fe r en t

meter

routes and read on different days.

par t icu la r ly i f each customer's meter is read on the same date each month.

Example 9 i l lu st r at es a s i t ua ti on of three reading dates per month.

consumption

i s

prorated for each

meter

route or book.

They ar e usu ally assigned

Therefore, a more

deta i led meter lag correction should be used for each

meter

reading r oute,

Again the



The

water a ud it period is

the

same a s above, January 1 t o December 31.

t h r ee meter routes are read bimonthly:

B

on

the

10th

of the

month; and route C on the 20th.

EXAMPLE

9

DETAILED METER LAG CORRECTION

The

route

A

on

the

1st of the month; route

The calendar below indicates the beginning and end of the water audit period

and the days of use for each meter route.

January 1 December 31

Water Audit

Period

I

End

--

I_

t a r t

I

December January February December January February

1 10 20 1 10 20 1 10 20 ...... 1 10 20 1 10 20 1 10 20

AAAAAAAAAAAA-

A A A A A A A A A A A A A A A W

BBBBBBBBBBBBBBBBBBBBBBBBB BBBBBBBBBBBBBBBBBBBBBBBB

cccccccccccccccccccccccc

cccccccccccccccccccccccc

Bi ll in g records issued during th e audit report would not include a l l of

the

water used during

the

audit period.

bi ll in g period, issued i n February, actu ally occurred i n the preceding

December.

The

l a s t bi l l in g period, issued i n November and December, would not

include water used i n December.

water used

in December before the audit starte d. Additional corrections

are needed

to

add water used i n December a t

the end

of t h e audit period.

The December through January billing period is 62 days long.

Route Read Date Sales Adjustment

Some

water shown a s used in the

f irst

So, corrections must be made t o su bt ract the

A 2/1/84

12 ac-ft 31/62 = -6.0 ac-ft

B 2/10/84

10 ac-ft 21/62 = -3.4 ac-ft

C

2/20/84

11 ac-ft 11/62 = -2.0 ac-ft

Water Use ................................ -11.4 ac-ft

A 2/ 1

85

13 ac-ft 31/62 = 6.5 ac-ft

B

2/10/85 10

ac-ft

21/62

=

3.4

ac-ft

C

12/20/85

12 ac-ft 11/62 = 2.1 ac-ft

Water Use

................................ +12.0

ac-ft

+0.6 ac-ft

Many water utilities have combined t h e i r accounting and billing procedures into

a computerized format t o

make

t h e foregoing procedure easier and quicker.

Enter Adjustments Due t o Meter Reading Lag time on Line 6 of

the

Water Audit

Worksheet.

2 3



Add

a l l

metered

deliveries and enter

the

t o t a l on L i n e 7 of the Water Audit

4

Worksheet.

Step 3. Verify and Adjust Metered Use Quantities

Because of their la rg e number, not a l l sa le s

meters

can feasibly

be

inspected

and

tested

annually. W

recmend

instead that you annually inspect and

test

a l l meters t ha t a re

mre

than two inches

i n

diameter and conduct a random

sample of meters equal t o or less than two inches in

diameter.

Review

your agency's practices on meter se lection, s iz ing , and ins ta l la t ion to

see whether present practices permit accurate operation and, i f not, which

practices should be revised (see Appendixes B,

C, D ,

and E for references).

Cornmercial and industrial

meters

produce a much larger share of revenue per

account than do res ident ia l

meters.

Commercial and industrial accounts should

be

inspected for proper type, si zi ng , and ins tal la ti on .

t ha t a l l

new

l a rge meters be inspected and tested before use.

meters

are accurate.

Sampling Residential Meters.

t o inspect and test.

t i a l

meter

t e s t i ng

w i l l

require test equipment that

differs

from that used for

larger meters.

factorv or a consultant for testing. (Refer t o American Water Works Associat ion.

I t i s

a l so recommended

Not a l l new

Choose a random sample of residential

meters

W suggest tes t in g a t lea st

50

t o 100

meters.

Residen-

Residential meters may

be

tes ted on a test bench or sen t t o the

~~

AWWA, publication No. M6, Water

Meters

- Selection, Installation, Testing, and'

Maintenance, Chapter

6 ,

"Maintenance and Repair of Displacement

Meters

. I)

4.

Correct m eter installations Include

a

small byp ass meter, a debrls screen,

and check valves on both sides of the

meter.



Many agencies a re involved i n a meter change out program.

If

you are involved

in such a program, be sure t o include i n the randcm sample some of the meters

being replaced

so

you can calculate t h e appropriate

meter

error for the e n t i r e

res ident ia l

meters

before use.

Calculating Total Sales

Meter

Error.

meter errors from a l l

meter

size s-- resi dent ial, commercial, and in du st ri al .

Residential

meters

are normally tested a t low, medium, and high-flow ra tes .

The registration data, normally expressed i n percent accuracy, is used to

calculate the t o t a l meter erro r a t average flow rates .

which follow, demonstrate how t o use your ex is ti ng

meter

test data and

ca lcula te to ta l res ident ia l

meter

error .

Table

2

was produced for 5/8

x

3/4

inch

water

meters

from information

i n

an

a r t i c l e by Penchin Tao wri tt en fo r Journal of th e American Water Works

Association, (" St at is ti ca l sampling technique for cont rol ling the accuracy

of small water meters," June 1982").

meter oper ates a t each flow ra te ; the range of flows for each flow ra te ; and

t h e

average

flow

for low, m e d i u m , and high flows.

system. I t is

reconanended t h a t you

test

a representative sample of

the

new

Total sales

meter

error includes

Examples 10 through 14

The

table shows the percent of

time

the

Percent of Time Range in

GPM

Average GPM Percent Volume

Percent Volume

refers

t o the proportion of water consumed a t the specified flow

r a t e , as compared t o t he t o t a l volume consumed a t a l l ra te s.

2.0 percent of th e t o t a l water consumed occurs a t

t h e

low-flow range of

approximately 0.5 t o

1

gpm.

Instead of using the percentage of volumes a s shown above, you may want t o

recording meters, you can

determine

the actual flow rates for your customers'

water meters.

Therefore, only

compute your own percentage volume data. By using special dual meter yokes and

25



EXAMPLE

10

ADJUSTING RESIDENTIAL METER RE CORDS

FOR SALES METER ERRO R

Volume

(VI)

Residential meter records were adjusted using total residential water sales

data

from

Example 7, Uncorrected Total Metered Water Use, and t h e following

meter

test data.

METE R TESTING DATA FROM A RANDOM SAMPLE OF 50 METERS

Test Flow Rates

Mean Registration i n Percent

Low flows (0.25 gpm) 89

Medium flows (2.0 gpm) 95

High flows (15.0 gpm) 94

Total Volume

Sal es a t Flow

Meter

Meter Error (ME)

Volume Rate Regist ra tion ME

=

V f

-

V f

( V t ) ( V f )

( R ) ( O X l R )

Meter Error

(ME)

( i n

ac-ft)

17.6

63.8 7,115

4,539.4 95 [(4,539.4/0.95) - 4,539.41 238.9

34.2 7,115 2,433.3 94 [(2,433.3/0.94) - 2,433.31 155.3

__

1

I_

100.0 7,115.0 TOTAL Residential Meter Error

=

-12.1

To calcu late to t al meter error for large meters, u s e your mean registration

da ta a s shown i n Example

12.



EXAMPLE

12

METER TEST DATA FOR LARGE METERS

Meter

ID

No.

Date of

Meter Installa- Manufac- Test Mean Registration at

Size Type tion turer Date Various Flow Rates

Low Medium

-

XYZOOl

3

in

Turbine

6/83

Rockwell

10/84 89 85 100

XOOZAA

3

in

Turbine

6/83

Rockwell

10/84 70 88 98

NB123 4 in

Displace

7/80 Sparling

10/84 95 99

102

NE456 6

in

Compound

9/77

Sparling

10184 98 92.5 102

MOO2

6

in Propellor

5/66

Hersey

10184

_.

8

-

8

-

03

Sum

of Mean Registrations

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

450 462.5 505

Mean Registration for

5

Meters Tested

------------------- 90 92.5

101

5.

Comm ercial meters m ay be tested,

repaired and calibrated

on

a meter

test bench.

27



EXAMPLE

13

CALCULATION OF METER ERROR FOR LARGE METERS

Volume

(%V I

Flow recordings

were

made fo r 24 hours in Jul y and February 1984 and indicate

the percent of

volume

delivered by large meters a t low, m e d i u m , and high-flow

ra te s a s fol lows:

Low

10

percent

M e d i u m 65 percent

High 25 percent

From t h i s information

the

to ta l sa le s volume for l ar ge

meters

was adjusted

a s

follows:

~~~~ ~

Total Volume

Sales

a t

Flow Meter Meter Error (ME) Meter Error

Volume Rate Registration

ME

=

V f

-

V f

(ME)

( V t ) ( V f 1 (R)

(0Xl)R ( i n ac-ft )

28



EXAMPLE 14

CALCULATION OF TOTAL SALES METER ERRO R

Total Sales

Meter

Error (TSME)

=

Residential

Meter

Error

+

Large

Meter

Error;

therefore,

from the totals in Examples

11 and 13, the TSME is:

TSME = 412.1

+

92.0

TSME

=

503.74 acre-feet

E n t e r

adjustments for Total Sales Meter Error on

L i n e 8

of the Water Audit

4.

Worksheet.

Add

Line 7 t o Line 8 and enter

the

total on Line

9 ,

Corrected

4

Total Metered Water

Deliveries.

Estimating Increased Revenue.

water audit

s the

potential increase in revenues from test ing and repairing

One of

the

major benefits of conducting a

t h e

larger

meters.

large

meters

found t o

be

operating inaccurately.

Again,

t h e

calculat ion for

the

corrected

metered

volume,

CMV,

for each

individual

meter

uses the following formula:

One

can estimate changes

i n

revenue from customers

w i t h

UMV

= O M R

Where

Uncorrected Metered Volume,

UMV,

is the volume of water registered on

the meter

(from

the

b il li n g records), Mean Registration,

MR, is t h e meter

accuracy i n percent.

For Example:

UMV

= 10,000 cubic-feet (from bil l ing records)

MR

= 75% (r eg is tr at io n accuracy

determined

by meter

tests)

10

000

cMV o 75)

=

13.333

cubic-feet

29



EXAMPLE

15

POTENTIAL REVENUES FROM RECALIBRATED LARGE METERS

(2)

( 3 )

Uncorrected Charges

Metered Billed

( 1 )

Volume

12 months

Meter I D (UMV) $

(4) (5) (6)

Corrected Charges for

Increased

Metered

Corrected Revenues

Volume Volume

$

(

CMV)

12 months Col

5 -

Col

3

$

Task 3. Quantify Authorized Unmetered Uses

Step 1. Identify Authorized Unmetered Uses

Many water u t i l i t i e s have some unmetered beneficial uses of water.

generally called authorized unaccounted-for

water.

sca tte red throughout the servi ce area a t public buildings, open-space public

areas, and special f ac i l i t i es designed to protect

the

public.

conducting an audit must conEirm

these uses

as unmetered in their service area.

The following authorized uses of water a r e frequently unmetered.

These

are

They a r e most o ft en

Employees

Firefighting and Fire-

fighting Training

Flushing of Mains

S t o rm

Drain Flushing

Sewer Flushing

Street Cleaning

Schools

Landscaping i n Large Publ ic Areas

Decorative Water Facilities

Swimning Pools

Construction Sites

Water Quality and

Other

Testing

Process Water a t Treatment Pl an ts

NOTE: If

any

of these

uses are

metered,

they should

be

included with

Uncorrected Total

Metered

Water Use ( L i n e

5).

Step

2.

Estimate Authorized Unmetered Uses

Unmetered volumes of water must be ca re fu ll y estimated t o produce an accura te

water

audit.



t he durat i on of operat i on ( di scharge procedure). Survey al l l ocat i ons

( such as school s, st or es, apar t ment s, i ndust r i al si t es, l umber yar ds, or ware-

houses) and i nspect check met ers t o acqui re such data.

survey, t he bet t er your chances of i ncl udi ng water used i n t est i ng, l eaky

spr i nkl er syst ems, or i ncorrect l y connected spr i nkl er systems.

Add

t he r esul t s t o det ermne total water use f or Fi ref i ght i ng and Fi r ef i ght i ng

Fl ushi ng of Mai ns. Thi s water use i s def i ned as unmetered water vented

f r omt he di st r i but i on system ( f requent l y t o stormdrai ns) t o cl ean t he system

of cont amnant s and debr i s.

Many ut i l i t i es have st andard f l ushi ng procedures and mai nt ai n l ogs of f l ushi ng

act i vi t i es, i ncl udi ng t he l ocat i on of t he mai n or bl owof f and the l engt h of

t i me i t f l owed.

Some agenci es even meter t he amount of water rel eased. As

w t h al l wat er uses, i f met ered, t he t ot al shoul d al ready be i ncl uded i n Li ne

5,

Uncor rected Tot al Metered Water Use.

Est i mat i ng wat er used i n the f l ushi ng of mai ns requi r es a seri es of di schar ge

est i mates. For each l ocat i on f l ushed, mul t i pl y the f l ow r ate by t he dur at i on

of t he di scharge.

m nut es equal s 1,500 gal l ons of water. I f t he di schar ge r at e i s not const ant ,

cal cul at e t he vol ume by f i gur i ng t he area under a curve.

di scharge f l owed const ant l y for

10

mnutes at 50 gpm was uni f ormy r educed t o

10 gpmover t he next

15 m nut es, and was then shut of f .

The mor e compl et e your

Tr ai ni ng and ent er t hi s on Li ne

11A

of t he Water Audi t Worksheet .

For i nst ance, 50 gal l ons per m nut e (gpm rel eased f or 30

I n Exampl e 16, t he

6.

Hydrant flushing prog rams

water quality

improve



Storm Drain Flushing.

used

t o f l u s h and clean such areas as storm drains, culverts, or catch basins,

is defined as storm drain flushing water use .

To

estimate the total water used for

storm

drain flushing, contact the

readings.

system,

f l u s h mains (discharge).

method.

Enter the total water volume used for storm drain flushing on L i n e 11C of

Sewer Flushing.

used t o f lus h and clean sewers and additional water used i n sewage treatment

plants for treatment processess and maintenance is defined as sewer flushing.

Water from the distribution system ( f i re hydrants)

maintenance department for logs of cleaning activity, including truck

cap aci ti es, number of trucks, truck f i l l i n g frequency, and por tabl e

meter

I f

t he

water

is

supplied directly

from

th e piped dist rib uti on

follow the

same

methods as those used

i n

estimati ng water used t o

If the water is transported by truck, use th e batch

the Water Audit Worksheet.

Water from the distribution system (usually f i re hydrants)

Follow the above Storm Drain Flushing procedure t o est ima te the total water

used for sewer flushing.

Enter

the total water volume used for sewer flushing on Line 11D of t h e Water

Audit Worksheet. c

Street Cleaning.

by direct release from hydrants or sprayed from trucks, sweepers, or other

equipment.

areas, and bikeways.

Estimates usually

w i l l

require

use

of

the batch method.

street department t o find o ut how many times a day the tank trucks and sweeping

equipment were f i l l e d , th e number of trucks used, t he truck capacity, and th e

number of days used during t he year.

frequency of use for washing recreational ramps and paths. I n Example 17 the

to ta l ga l lons used annually

was

1,750,000.

This water

u s e

is defined as

water

used t o clean roadways

I t inclu des cleaning park walkways, boat ramps, bus stop s, parking

Check with the

A l s o identify the equipment type and

7.

Records should

be

malntalned

water used for street cleaning.

of



8.

Cemeteries may

b e large water

users.

To est i mate t he di schar ge f or l andscapi ng, you w l l need t o know 1) t he

di schar ge r ate at each suppl y pi pe to an i r r i gat ed area, and

(2)

t he t ot al

amount of t i me t he water i s appl i ed at each area. Ti me cont rol l ed i r r i gat i on

syst ems make t he t i me determnat i on easi er.

remember t o use the tot al t i me t he suppl y servi ce i s di schargi ng,

rat her than

j ust t he subper i od f or one l ateral .

I n maki ng these est i mates,

EXAMPLE 18

ESTIMATE OF LANDSCAPE WATERING

A si ngl e 2- i nch ser vi ce provi des i r r i gat i on wat er t o 4- 1/ 2- acre Sunnysl ope Park

at t he r at e of 160 gpm

water and i s cont rol l ed by

a

common t i mer.

Lat er al A operates from 1:00 a.m t o 3:OO a.m

3:OO a.m t o 5: OO a.m Lat er al C operates f rom5:OO a.m t o 7:OO a.m

The system i r r i gat es accordi ng to the f ol l ow ng schedul e:

May and Sept ember

..........

every 3rd day

J une ....................... every 2nd day

J ul y and August

............

dai l y

Each of t hr ee l at eral s provi des equal amount s of

Lat eral

B

operat es f rom

How much water i s appl i ed f romMay t hrough Sept ember?

t he answer :

The ser vi ce suppl i es

160

gpmor 9,600gal l ons per hour (160 x 60).

oper ates 6 hours each day t he park i s watered.

gal l ons per hour x

6

hour s = 57, 600 gal l ons

of

water appl i ed.

Here' s how t o work out

I t

Dur i ng t hose si x hour s, 9,600

The number of wat er i ng days must now be cal cul ated:



The principal components of normal water l os se s from open-air, standing bodies

of water are:

o evaporation

o

water d rained from a pool during maintenance

o

water used for cleaning

o

leaks

To estimate the evaporative loss components, refer to Appendix I (page 1 2 3 ) .

To estimate the water loss from pool drainage, use

the

following data: th e

volume of the

p o o l ,

t h e l i k e l y level t o which t h e pool evaporated before being

drained, and

the

frequency of draining.

Use t h i s

formula:

V x F = V w

V = volume of pool a t time

i t

is drained

F

=

frequency of pool draining

Vw =

volume of water

loss

due t o pool drai ning

To

estimate the water lost

i n

cleaning, f i rs t t a l k t o the maintenance people

involved. They can identify cleaning and flushing frequencies and pool

volumes.

source is a hose b i b

from

a metered fac i l i ty , no further ca lcula t ion

is

necessary.

For an unmetered water source ask how much time th e maintenance work r eq ui re s

a f t e r the pool is drained.

running during

t h i s time.

r e f i l l

pipe,

or

hose, and calculate

the

volume used.

To estimate the

losses from leaks i n decorative water f ac i l i t i e s , you can

sub tra ct th e average amount t h at should be l o s t t o evaporation

from the

normal

water volume. The difference

is

water t ha t i s leaking from the f a c i l i t y .

After you have estimated the four components of water losses (evaporation,

drainage, cleaning, and leaks) add t he results to obta in a tota l for t h i s type

of water loss.

buildings) w i t h i n your s er vi ce area.

E n t e r

the

total water volume used for decorative water facilities

on

L i n e

1 l H C

of th e Water Audit

Worksheet.

They most l i k e l y use a hose from some convenient source. I f the

Ask i f the unmetered hose or

ref i l l

pipe was

Determine

t h e

flow rates for

the

appropria te o ut l e t ,

Add

the

losses by type of f a c i l i t i e s (fo r example, parks

or

Swimnin

Pools. This

water use

is

defined as water used t o maintain volume

and walkways, and operat ion of assoc iated s an it ar y and drinking water f a c i l i -

ties.

Any unmetered water use by concessionar ies th a t depends on t h e service

t o the pool should a ls o be included.

Pools

w i l l

probably

be metered, i n which

case the i r use w i l l already

be

counted

as a metered use.

S w a

--Ir

qua i t y , inc lud ing make-up water,

f i l te r

cleaning, cleaning of

decks

If they are not,

determine

unmetered water uses by pools and



associ at ed f aci l i t i es f rom i nf ormat i on provi ded by oper at i ons and mai nt enance

staff.

of si ml ar si ze and use.

Enter t he t otal water vol ume used f or al l unmet ered pool f aci l i t i es on Li ne

111 of your Water Audi t Worksheet .

Const ruct i on Si tes. Wat er use at const ruct i on si t es i s def i ned as water

pr i nci pal l y del i vered through hydrant s t o t r ucks f or road dust cont r ol , si t e

pr eparat i on, l andscapi ng, temporary domest i c use, and mat er i al s processi ng ( f or

exampl e, concr ete mxi ng).

To est i mate t hi s t ot al water use, obtai n consumpt i on dat a f rommetered

const r ucti on si t es f or si ml ar proj ects.

wat er agenci es. Compare a contra' ctor' s pract i ce i n shut t i ng of f suppl y at

unmet ered si t es w t h the pract i ces at metered si t es and compensat e f or t he

di f f erence.

We recommend that al l cont r act ors be requi red to use a port abl e meter and

r epor t t he readi ngs.

Enter

the t ot al wat er vol ume used f or const r uct i on si t es on Li ne

11J

of your

Water Audi t Worksheet.

Usef ul est i mat es can be made by compar i ng water use w t h metered pool s

4

Data may be obt ai ned f romregul at ory

4

Water Qual i t y and Ot her Test i ng.

t o t est di st r i but i on syst emout put to meet publ i c heal th st andar ds and to test

Thi s water use i s def i ned as water used

met er s and new mai ns.

Est i mate water used i n water test i ng by cont act i ng operat i ons st af f to

determ ne t est i ng f requency and durati on and vol umes of water used.

w l l probabl y vary w th each user.

Li ne 11K of t he Water Audi t Worksheet .

Process Water at Treat ment Pl ants.

recycl ed) af ter f i l t er washi ng or sedi ment at i on basi n drai nage at r aw water

t reat ment pl ants.

Est i mate t hi s t ot al water use by agai n contact i ng pl ant oper at i ons st af f and

checki ng records.

Enter t he total water vol ume used f or process water at t reat ment pl ant s on Li ne+

11L of the Wat er Audi t Worksheet .

Amount s

Enter t he t ot al water vol ume used f or water qual i t y and other t est i ng on

c

Thi s i s def i ned as water l ost (not

You may di scover an unmetered use t hat does not f i t any of the previ ousl y

descr i bed categor i es.

used on Li ne 11M of t he Water Audi t Worksheet .

Now, add al l t he aut hori zed unmetered water uses ( Li nes 11A t hrough 11M) and

enter t he t ot al on Li ne

12

of t he Wat er Audi t Worksheet.

I f so, descr i be t he use and enter t he t otal water vol ume 4

4

39



Task 4. Quantify Water Losses

Al l wat er t hat i s not i dent i f i ed as aut hor i zed unmet ered water i s consi dered t o

be wat er l ost f r omt he di st r i but i on system

r evenue and i s unavai l abl e f or other benef i ci al uses. To determ ne Tot al Water

Losses subt r act Tot al Author i zed Unmetered Wat er ( Li ne 12) f romCor rected Tot al

Audi t Worksheet .

Thi s water does not produce

Unmetered Water ( Li ne 10) and enter t he di f f erence on Li ne 13 of t he Water 4

Step 1. Identify Potential Water Losses

Wat er l ost f r omt he di st r i but i on systemi ncl udes underground l eaks and other

l osses Li sted bel ow

account i ng f or al l t he other l osses and subt ract i ng them f romt he Tot al Water

Losses shown on Li ne 13.

Water l osses other than l eakage can general l y be at t r i but ed to t he f ol l ow ng

causes:

The t otal amount l ost t o l eaks can be determned by

account i ng pr ocedur e er rors

i l l egal connecti ons

mal f unct i oni ng di st r i but i on syst emcont rol s

reservoi r seepage and l eakage

evaporat i on

reservoi r over f l ow

di scovered l eaks

theft

Step 2. Estimate Losses by

Type

of Loss

Thi s st ep i dent i f i es t ypes of water l osses and methods of est i mat i ng thei r vol ume.

10.

Meter readers must cope with

different meter dials and un lts of

measure.



Accounting

_ _ _ _

rocedure Errors.

&cause

of

overlapping b i l l i n g cycles (see discussion of A d j u s t m e n t s Due t o

Water may seem t o be l o s t from the system

Meter

Reading Lag

Time,

(page-21

j ,

misread

meters,

improper-calculation methods

based on data

from meters

or other sources, computer prog raming er ro rs , or

other discrepancies.

computer process.

and

the

water

b i l l

may

be

calculated in gallons.

conversion factor would introduce error

i n

such a case.

Basically,

these

types of losses are paper mistakes that

can

be

identified by careful, step-by-step review

of

the record collecting and

For example,

the

water

meter

may be calibrated

i n

cubic-feet

Use

of an incorrect

The entire billing and accounting procedure from meter reading t o to t a l water

use and printing of billing statements should

be

reviewed.

the accounting and billing functions are scattered among several departments or

organizational units.

t ion.

sample

from

the total number of accounts.

Each

meter

route

book

should

be

checked, t o ver ify

a

sample number of accounts

from

each book (or

meter

route).

I n

some agencies

Such a fragmented arrangement can lead t o miscomnunica-

The

task of reviewing can

be

simplified by checking a representative

The

steps are:

Determine the

number

of accounts to

be

checked from each book or rodte.

Choose a random sample of accounts t o

be

checked.

Have an employee other than

the

regular

meter

reader read the ident i f ied

accounts,

or

send another employee t o accompany

the meter

reader

to v e r i f y

the meter reader's readings.

day i f possible.

being read and recorded properly and

i f the

conversion fa ct ors a r e being

used properly.

Calculate the bi l l ing of

the

identified accounts by

hand.

Compare the identified accounts for total water use

with

billed amounts.

Do

they agree?

If

not, what

i s t he

reason for the inconsistency?

If meter

book readings show a substantial difference from the accounts

t h a t were

checked, review

t h e normal b i l l i n g process step-by-step, line-by-

l ine .

Both

readings should

be

taken on t he same

The

purpose

is

t o determine

whether

the regis ter . is

Compare

the

water use volume for both

meter

readings.

Enter th e t o t a l water volume due t o accounting errors o n L i n e 14A of the Water+

Audit Worksheet.

I ll e ga l Connections. Ide ntif y ac tiv e connections

where

unauthorized water

use

is

not included

i n the

accounting and billing process.

of

water

is

usually,

but not

always, accidental rather than deliberate.

Examples include t ap s t o unmetered f i r e l i ne s

i n

a building ( i n s t a l l e r may have

been unaware that

the

l ines are reserved for

f i r e

control); a customer might

water; connections erroneously cl as si fi ed a s inac tive may in f a c t

be

i n

use;

meters

might not

be

read or

the

readings may not

be entered

i n t o

the

accounting

system.

Connections

l i s t e d

as inactive should

be

confirmed as inactive. A

well-programed computerized bi l l i ng process may di sc lo se $uch improper pr ac ti ce s.

Unauthorized use

t ap i n t o t he main or someone else's service and thus avoid paying for the

Determine whether the account i s in ac tiv e or ac tiv e. Has t h e meter been

41



removed or locked i n the "offt1 position?

reader periodically check the inactive accounts to

see whether

there has been

use?

To id en ti fy i l l eg a l and unauthorized use, compare a l l act iv e and inact ive

accounts

with

a l l locations th at could receive water. One

method

is

to write

the

ident i f ica t ion

numbers

on the distribution system map and check that each

parcel has a

meter.

likely places of water use and, where possible, correlate them with account

numbers on a map.

and assessor's parcel number.

investigated.

metered.

Compare

the

number of accounts.

period?

accounts.

during the latest complete billing cycle?

and multiply by

t h e

average annual customer

water

use.

E n t e r

the total volume for illegal connections on L i n e

14B

of

the

Water Audit-

Worksheet.

Malfunctioning Di st ri bu ti on System Controls . Water

loss

may r e s u l t

from

improper app lic ati on, Xal funct ionin g and improperly set system controls.

The basic steps for determining the volume of loss remain the same: determine

t h e r a t e of loss,

the length of time during

which

the loss

occurred,

and the

frequency of

loss.

Valves are the controlling devices i n water distribution systems.

used fo r both is ola ti on

and

control functions.

manually operated, and control valves function automatically.

indicators that show the position of the valve.

t o

see whether

they a r e positioned properly.

with indicators to show

t h e i r

open

or

closed

position.

A l l

control valves

w i l l

f a i l sooner or la ter .

A s part of

the water

audi t ,

it

is important t o inspect each ins ta ll at io n th at uses automatic system cont rols

and determine whether

the

valve is working, whether it has been

set

properly

for the particular si tuation, and

whether

i ts size and design are suitable for

i t s

intended purpose.

If

neither is

t r u e , does the meter

Telephone c a l l s or v i s i t s t o th e premises may help.

A

second method

i s

t o

use

an aer ia l photograph t o iden tif y

A t h i r d

method

is

t o check each meter ident i f ica t ion number

Any parcels without an account number should

be

Some

water uses may not have an account

number

and/or may not

be

How many

existed

a t the s t a r t of the audit

Subtract those discontinued during the year. Add new or reactivated

Does the total equal the

number

of customers who have been b i l l ed

If not , to ta l the

number

of accounts

They are

Many valves have

Isolation valves are usually

Valves can also

be

re t ro f i t t ed

These can be inspected easily

A l t i t u d e

Control

Valves - Alt i tude control valves can cause a tank or

reservo ir t o sp i l l i f the valve

is

broken or set improperly.

normally set t o prevent the tank from overflowing.

The

valve i s

Pressure Relief Valves

- If t h e

pressure

relief

valve is

set

too

low

for

t h e

system's range

o

pressures, each

time the

pressure reaches

the

high

range, th e valve w i l l cause water t o s pi l l .

w i l l occur because a pressure regulating valve has been readjusted and the

pressure

relief

valve was not

reset.

Sometimes

an unnecessary spill



Pr essur e- Reduci ng, Pr essur e- Sust ai ni ng, and Pressure- Mai nt ai ni ng Val ves -

I f

any of t hese val ves i s i mproper l y set ,

i t can cause an al t i t ude cont rol

val ve, a pressure r el i ef val ve, or a sur ge cont r ol val ve t o spi l l wat er .

Sur ge Rel i ef Val ves

-

I f t hese val ves are set t oo l ow, t hey can spi l l

water unnecessari l y as a bl owof f to the at mospher e, i nto a tank or dr ai n,

or

back t o the suct i on wel l of a pump.

Pump Di scharge Val ves - When t he pump di schar ge val ve f ai l s, i t act s l i ke

a check val ve t hat i s par t i al l y open and may al l ow water t o di scharge f rm

t he di st r i but i on syst emback down t he wel l .

Enter t he t ot al

l oss

f rommal f unct i oni ng di st r i but i on systemcont r ol s on Li ne+

14C on t he Water Audi t Worksheet.

Reservoi r S e e s nd Leakage.

wal l s of st or age t anks or ponds.

and out f l ow of t he r eservoi r and not i ng t he change i n stor age l evel over

aever al days.

Because water may be l eaki ng onl y at cer tai n el evat i ons of t he cont ai nment

wal l s, t he seepage (or l eakage) t est shoul d be per f ormed sever al t i mes at

successi vel y l ower sur f ace water el evat i ons. Cl ear wel l s (pol i shed wat er

st orage) are al so subj ect to seepage and shoul d be i nspected regul ar l y.

Thi s i s t he l oss f roml i ni ngs, bot t oms,

or

Water l oss i s est i mat ed by cl osi ng t he i nf l ow

Fromt hi s i nf or mat i on, t he rat e of seepage can be cal cul at ed.

Water storage tanks m ay b e subject to

overf low an d leakage.

43



E n t e r the

t o t a l

loss from

reservoir seepage and leakage on Line 14D of

the


Evaporation.

l i n e d , which reduces evaporation si gn if ic an tl y. Some cl ea r wells and

Losses can be calculated by measuring

t'ne

surface area and applying

the

proper

evaporation data for your area

(see

Appendix

I

on page 123).

E n t e r t h e

total water volume l o s t to evaporation on Line l4E of the Water Audit 4

Worksheet.

Reservoir Overflow.

This

occurs most often because

the

al t i tude contro l

valve

is

faulty or missing.

discharge rate must be

determined.

t o

the

distribution system.)

example, by a stream gauge below

t h e

discharge point), the reservoir overflow

is calculated by subtracting rese rvoir outflow t o the distribution system from

the

i n f l o w

t o

the

reservoir.

deducted

f i r s t

from the reservoir inflow.

Most re se rv oir s t ha t s t o re tre at ed water ar e covered and

re re rv oi rs ar e open t o th e atmosphere and t h u s are subject to evaporation.

Both

the

periods of overflow and the overflow

(Overflow

does

not include

water

discharged

If the

discharge is not dir e ct ly measured (f or

For open reservoirs, evaporation losses should be

E n t e r

t h e t o t a l

water

volume l o s t t o re ser vo ir overflow on Line 14F

of the


Discovered Leaks.

be

measured t o determine the r a t e

of

loss and

the

total volume lost during

the

l i f e

of the leak.

under

t h e

section entitled llMeasuring and Estimating Losses from Discovered

Leaks" on page

75.

E n t e r

the t o t a l l o s s from discovered leaks on Line 14G on

the

Water Audit

Worksheet.

Theft.

hydrants.

water trucks or others who connnit acts of vandalism.

department construction permits

with

water utility temporary use billings, you

can

determine where

large amounts of water are being taken for which proper

metering and billing have not been arranged.

E n t e r the total water

volume

lost from

thef t s

on L i n e 14H on t h e Water Audit

Worksheet.

Now, add a l l

the i den t i f i ed

water losses (Lines 14A through 14H) and enter

the

total on Line 15

of


Losses from lea ks t h a t a re discovered and repa ired can

Methods of estimating leak rates,

with

tabl es, are described

Most water t h e f t occurs when water

is taken illegally from f i r e

This

usually involves individuals

who

open t he hydrants t o

f i l l

By comparing bui ldin g

Task 5 Analyze the Water Audit Results and Consider Corrective Measures

Analysis of

the water

audi t

results

may indicate

loss

problems in the

water

distribution system.

These

could

be

faul ty metering, i l le ga l taps (such as

firelines), leaking reservoirs, or leaking mains and

services.

corrective efforts would be

cost

ef fec t ive

to

implement.

be able to est imate t he value of t h e leaking water that can

be

recovered and

the cost of recovering it.

Determine

which

To

do so,

you need t o

If the

value of the recoverable water exceeds

the



costs, then your agency should

carry

out the appropriate leak detection and

repair program.

The following paragraphs

i l lustrate

the benefit cost procedure for a leak

detection survey.

To determine Po ten ti al Water System Leakage, su bt ra ct Tota l Ide nt i f ie d Water

Losses (Line

15)

from

Total Water Losses

( L i n e

13) .

E n t e r

t he re su l t

on

L i n e

16 of t h e Water Audit Worksheet.

Not

a l l

leaks can be detected and repaired.

Some

a r e e x t r e m e l y small; however,

estimates indicate that

75

percent of a l l potential

water

system leakage can be

recovered.

Water System Leakage

( L i n e 16)

by 0.75 and

enter

t he re su l t on

L i n e 17,

Recoverable Leakage.

L i n e

18, Cost Savings, is the cost savings that would be achieved

i f t h e

leakage was prevented.

purchase cost and variable operations and maintenance

(O&M)

costs.

costs that vary with the amount of water delivered into the distribution

sys t em

and both exclude fixed costs.

The purchase cost is

the

"Cost of Water Supply" due t o purchases of water for

the distribution system

from

another water supplie r. The amount of leakage

prevented

w i l l

reduce th e amount purchased from t ha t source. Usually, the most

effective cost reduction

w i l l resul t

from reducing

t h e

amount of water pur-

chased

or

produced from the most expensive source of supply. E n t e r the cost

per u n i t your agency pays for

i ts

most expensive water supply on Line

18A

of


The O&M cost

is the

V a r i a b l e

O&M

Costs

saved by reducing the amount of

water

th at has t o be tr eat ed and pressurized i n the system.

water from

i ts

own

wells,

it w i l l reduce the amount of energy needed for

pumping.

NOTE:

dis tr ibu tio n system ar e t o be included.

amount of water delivered should not be included.

E n t e r

the unit costs of

~ r = ~ o p e r a t i o n ~ ~ ~ m a i n t e n a n 6 ~ - o n

i n e

18B of t he Water Audit Worksheet.

Add Costs of Water Supply (Line 18A) t o Variable O&M

Costs

( L i n e

188)

and

enter

t h e total on L i n e

19,

Total Costs Per Uni t of Recoverable Leakage.

To determine the One-Year B e n e f i t from Recoverable Leakage, multiply

Recoverable Leakage ( L i n e

17

by Total Costs

Per

U n i t

of Recoverable Leakage

(Line

1 9 ) .

Since the average lifetime of a leak

is

estimated a t two years, the to t a l

benefit from recoverable leakage

is

the value of the water saved over two

years. Therefore, t o compute the Total Benefit s from Recoverable Leakage,

multiply One-Year

Benefits

from Recoverable Leakage ( L i n e 20) by two and enter

the product on Line 21 of t he Water Audit Worksheet.

The cost of conducting a Leak Detection survey can be estimated

by

preparing a

Therefore,

calculate recoverable leakage by multiplying Potential

There

ar e two types of cost savings t o be realize d,

Both are

If the agency pumps

O nl y

O&M costs that vary with the amount of water del ivered in to the

-

ixed

-

osts that do not vary with

t h e

Enter the product on L i n e 20 of the Water Audit Worksheet.

4

4

45



Leak Detection and Repair Plan.

prepare the plan.

of the Water Audit Worksheet.

The cost of leak repairs

i s

not entered. DWR conducted an economic analysis

Refer

t o

Chapter 4 for suggestions on how t o

Enter the Total Costs

of

Leak Detection

Project

on L i n e 22

c

en t i t l ed An Examination of the Benefits of Leak Detection.

found that a

major

benefi t of a leak detection

roara am

i s the reoa i r costs

The analysis-

__ _____l___l ll

_

. -

avoided (leaks repaired i n t he f utur e)

as

a r e su l t of t he program.

a r e cont inually discovered and rep air ed i n th e normal

course

of t h e u t i l i t y ' s

operations,

t h e

leaks found

i n the program would have eventually been repaired

a t some time i n the future .

detection program, the u t i l i t y w i l l avoid the expense of repairing them as they

ar e discovered acc identally.

often overlooked

when

estimates

of the savings from leak detection are made,

can often be nearly as great as

t he cost

of repairing th e

leaks

as par t of the

program.

For example, when the average l i f e of the leaks is 24

months

and the real

interest

r a t e

is

3

percent , the benefi ts

from

avoided

future

repair

costs

amount t o

94

percent

of the

cost

of

repair ing the l e aks a t t he time

of

the

program.

repairing the leaks found i n the program.

of repairs has been assumed

t o

be zero.

To

determine the Benefit

t o

Cost Ratio, div id e Total Benefits

from

Recoverable

Enter the

result

on

L i n e

23 of t he Water Audit Worksheet.

If t h e

Benefit to

Cost Ratio

i s

greater than

1.0,

then t he ben ef it s of a water

audit and leak detection survey are grea ter than th e cost s, and a leak

detection program should be performed.

Since leaks

If these leaks are repaired a s par t of a leak

These savings i n f u t u r e repair costs, which are

The

rea l cos t

of

repairing leaks in a program is generally very small.

In othe r words, t he real

cost

is only 6 percent of t he cost of

To

simplify the calculation the cost

Leakage (Line 21) by the Total Costs of Leak Detection Project ( L i n e 22).

c

REFERENCES

See

Appendixes

B

and

C

(pages 103 and 107) for guidelines on choosing the

appropriate meter

for

different appl ica t ions.

See Appendix D (page 111) for guidelines on choosing

meters

of the proper

size.

See Appendix

E

(page 115) for dir ecti ons on meter ins ta l la t ion .

with

the

equipment manufacturer f o r guidel ines .

See Appendixes

F

and G (pages 117 and 119) for meter testing procedures.

See Appendix

H

(page 121) regarding long-term

meter

surveil lance.

Also check



CHAPTER 3. LEAK DETECTION

Visible and Nonvisible Leak s

Vis ible

____

leaks are those leaks that surface and can be seen emerging

from the

ground or pavement.

from the area where

i t i s

observed.

customers.

The

source

of t h e

lea k may be a cons iderable d is t anc e away

Many visible leaks are reported by water

Nonvisible___ Leaks include leaks that percolate into the surrounding ground and

leaks tha t enter other conveyance facilit ies such as storm drains,

sewers,

stream channels,

or

old abandoned pipes.

feet

of leakage occurs in California each year from nonvisible leaks.

DWR

estimates tha t up to 250,000 acre-

hyd rant, are easily found. und erground .

47



NON-VISIBLE LE A K

HYDRANT

2. Nonvblble L u k

Examples of UndergroundLeaks

Water

w l l tak e the path

of

least resistance and may not surface.

s t a r t small and grow larger

over

time.

an average l i f e of

two

years.

underground cav it y get s l ar ge r

which

increases the po tent ia l

for

damage to

overlying property.

following paragraphs i l l u s t r at e a few of them.

City of Beverly H ills

The leak detection team detected sounds

of

leakage on numerous

services

and

used the ground microphone t o pinpoint a main leak.

main with a

pressure

of

80 pounds per square inch ( p s i ) had

a

leak

from

a 1/2-

inch hole

i n

the top of t he main.

lea k was calc ul at ed

to

be

53

gpm.

year du ra tion was 171 acre-feet. The value of th e water lost was calculated t o

be $43,000.

Most leaks

As

the age and

s ize

of

leaks increase , the

There a r e many examples

of

leaks that never surface.

Most nonvis ibl e underground l ea ks have

The

An

8-inch-diameter steel

No evidence of leakage was visible.

The

water

lost

from

t h i s l e ak fo r t he

two-

The

Placer County Water Agency

The leak survey crew detected leak sounds on a f i r e hydrant served from a 4-

inch cast iron main.

pinpointed and found in s id e an 18-inch concre te cu lver t.

from a h i l l s i d e , crossed a road, then terminated in a ravin e. Debris carried

through th e cu lver t over t he ye ar s had damaged th e 4-inch main and caused an 18-

gpm leak which drained

in to

the cu lver t.

Using t h e ground microphone, t h e leak lo ca ti on was

The main crossed

through the inside

of

Fne cu lv er t pipe. The cu lv er t pip e drained storm runoff

Over

Fne two-year pe rio d,

58

acre-

8



feet valued a t $2,900 was l o s t through the leak .

City o f Petaluma

The leak detection crew detected leak noise at several services.

ground microphone, th e crew pinpointed t he leak on an abandoned galvanized

service

l i n e

that had not been shut off. The water l o s t from th e 5-gpm leak

for t h e two-year dur ati on was 16 acre -feet. The value of

the

water lost was

$4,250.

Using the

Walnut Valley Water District

The leak detection crew detected a leak sound on a hydrant and service meter.

The leak was pinpointed by using a c or rel at or and found i n a 1-inch

PV C

service

l a t e r a l near t he connection t o a 10-inch asbestos-cement AC ) main

l i n e .

Pressure i n t he l i n e was measured a t

120 psi.

service

l a t e r a l and was measured using a bucket and stopwatch a t 12 gpm.

water l o s t from th e leak f or t he two-year dur atio n was

39

acre-feet.

of

the

water

l o s t was $9,600.

The

leak was

a

s p l i t i n t he PVC

The

The value

City of Santa Clara

The leak crew det ec ted a leak sound on a 6-inch duc t il e iron pipe.

pinpointed on th e main, was a circumferent ia l break caused by set tl eme nt .

Water from th e main was leaking into an adjacent sewer a t 98 gpm.

from t he leak f or th e two-year dur atio n was 317 acre-feet.

water l o s t was $47,000.

The leak,

Water lost

The value of the

14. Circum ferential break on a 6-inch

cast-Iron main.

The

flow rate was

98 gpm.

49



Value of Recoverable Leakage

Leak Rate

am

Most

agencies ar e not aware of the exi sten ce of nonvisib le lea ks and

the

value

of

detecting and repairing these leaks.

th e water system and do not generate revenue.

worth?

Table 3

shows

the

value

of

recoverable leakage based upon an average leak

l i fe-

time

of

two years

(from

"Leak Detection Productivity," by Douglas

S.

Greeley,

rates

and water costs.

Leaks are

the f i r s t

user of water on

How

much

i s

recovered leakage

Water Emergency

- - -

nd

Number 1981) and varying leak

Source of Supply

Value of Leaking Water

$/acre-foot

$/2

years

TABLE 3

VALUE O F RECOVERABLE LEAKAGE

1/11

1 4

114

1 4

1

1

1

1

5

5

5

5

25

25

25

25

100

100

100

100

50

100

250

500

50

100

250

500

50

100

250

500

50

100

250

500

50

100

250

500

40

81

202

404

162

324

808

1,615

R10

..

1,610

4,038

8;075

4.050

8;100

20,188

40,375

16,150

80,750

161,500

32 300

500 50 80,750

500 100 161,500

500 250 403,750

500 500 807,500



An Overview

of

Leak Detection M ethods

Water Audit

Thi s method i s an ef f i ci ent way f or det ermni ng t he t ot al vol ume and val ue of

wat er t hat i s l eaki ng f rom

a

wat er di st r i but i on system The water audi t i s

a

subt r act i ve process whi ch i ncl udes quant i f yi ng t ot al water i nt o t he syst em

wat er sal es, unmetered uses, wat er l osses, and r ecover abl e l eakage.

audi t al so i ncl udes

a

benef i t : cost anal ysi s f or r ecover i ng pot ent i al l eakage.

The f i nal part of t he wat er audi t i s t he preparat i on of a Leak Detect i on and

Repai r Pl an whi ch out l i nes t he equi pment , t ype of cr ew, method of surveyi ng and

pi npoi nt i ng l eaks,

and the cost s i nvol ved. Exampl e 19 i n Chapter

4

( page

59)

i l l ustr ates

a

Leak Detect i on and Repai r Pl an.

Audible Leak Detection

Thi s method uses el ect roni c l i st eni ng equi pment to det ect the sounds of

l eakage.

t he pi pe

wal l

and to t he surroundi ng soi l area. Thi s energy creates sound

waves i n t he audi bl e r ange whi ch can be sensed and ampl i f i ed by el ectroni c

t r ansducers or , i n some cases, by si mpl e mechani cal devi ces.

are then eval uat ed by an i ndi vi dual t rai ned i n l eak detect i on who can determ ne

t he exact l ocat i on of t he l eak.

i ni t i al l i steni ng survey of t he ent i r e di st r i but i on systemand r ecor ds al l

suspect sounds.

are pi npoi nted.

Ther e are t hr ee t ypi cal l eak sounds.

The water

Pressur i zed water t hat i s f orced out t hrough a l eak l oses energy t o

The sound waves

Thi s i ndi vi dual , t he oper at or , conducts an

I f t hese sounds ar e heard agai n when rechecked l ater , l eaks

The f i r st sound i s normal l y i n t he

15.

Valves are excellent co ntact points

for

sounds

of

leakage.



500 to

800

her t z (Hz)

range. I t usual l y or i gi nat es as an or i f i ce- pi pe

vi brat i on phenomenon and i s t ransmt ted al ong t he pi pe wal l -- i n sane

i nst ances

a

consi der abl e di st ance f romt he actual poi nt of l eakage.

i dent i f i cat i on of t hi s sound by systemat i c t est i ng of val ves, hydrant s,

and

curb val ves w l l f requent l y l ocat e potent i al l eaks.

Both the second and thi rd sounds are i n t he

20

t o

250

Hz range.

sound i s caused by t he i mpact of water upon soi l i n t he area of t he l eak.

thi rd sound resembl es t he sound of a f ountai n.

t i on, usual l y i n a cavi t y i n t he soi l near t he l eak.

t he pi pe wal l , t he t ravel di st ance of t hese t wo sounds i s l i mted t o t he

i mmedi at e area of t he l eak, and, . f or thi s r eason,

t hese t wo sounds ar e very

i mport ant i n pi npoi nt i ng the l eak for excavat i on and repai r .

The

The second

The

I t i s caused by water ci r cul a-

Unl i ke t he vi brat i on on

There are a number of f actors that i nf l uence l eak sounds, and t hese f actors

must be taken i nt o consi derat i on.

o

I_

ressure

-

I t i s usual l y necessary t o have

15

psi

or

more water pressure

f or soni c l eak detecti on.

o P&

_I____

at er i al and Pi pe Si ze - Because metal l i c pi pe i s

a

much better

sound conductor than nonmet al l i c pi pe, a cl oser test i nterval i s requi red

when searchi ng for l eaks on nonmetal l i c pi pe.

used, however, on pi pe and f i t t i ngs of any mater i al .

Sol-

-

The t ype of soi l great l y i nf l uences the amount of sound

t ransmt ted to t he surf ace.

normal l y a good conductor of sound; cl ay i s a poor conductor.

Surf ace-

-

The type of sur f ace on whi ch t he soundi ng i nst rument i s

pl aced i s anot her f actor .

asphal t and concr ete are good r esonators and gi ve a uni f orm soundi ng sur f ace.

They i ncl ude:

Soni c t echni ques can be

o

Empi r i cal observat i on i ndi cat es that sand i s

o

Sod tends t o i nsul at e and muf f l e sounds, whi l e

Zone Flow Measurements

Thi s method can reasonabl y be under t aken as an extensi on of t he water audi t or

i n some cases di rect l y as a l eak detect i on method.

whether a sector or zone77of a water system i s suf f er i ng maj or l eakage.

ef f ect i vel y conduct

a

zone f l ow measurement

a

ut i l i t y must mai ntai n good maps,

have val ves l ocat ed at zone cont rol poi nt s, and provi de a tap i n t he mai n f or

t he recordi ng pi totmeter .

Zone measurement s are most ef f ect i ve i n l arge resi dent i al or rural sect i ons,

l ess so i n commerci al or i ndust r i al areas. The w nter mont hs are t he best t i me

f or zone measurement s as they are l ess af f ected by out si de water use ( l awn

t emperature shoul d be avoi ded, si nce cust omers may l eave water runni ng t o avoi d

water l i ne f reeze-up. Twent y- f our - hour r ecordi ngs are recommended and dayt i me

f l ows are compared w t h ni ght t i me f l ows.

to ni ght t i me reservoi r f i l l i ng or unusual water usage such as ni ght i r r i gat i on

or a commerci al use such as a l aundry operat i on.

mni mum usage.

I t s purpose i s t o det er m ne

To

wateri ng

and

i r r i gat i on) . However , ni ght s that are subj ect to extreme f reezi ng

Water ut i l i t y staf f shoul d be al er t

Al l owances are made for

Fl ows great er than these mni mum f l ow rat es i ndi cat e l eakage.



Sections

of

t he water system are isolated and valves are closed to permit water

flow from a s in gle l ine .

the flow r a t e

i s

unacceptably high and warrants ad di ti on al in ve st ig at io n and

correction.

valving in

the

area of in te res t .

Another

form

of zone measurement

is

the

storage tank method.

and the the en ti re zone is supplied by st or ag e tanks.

read for volume and

a11

the customer meters i n the zone are read. During t h a t

time period, t h e stora ge tanks are not replenished.

such

as

a

week,

the procedure is repeated.

difference between the water supplied

t o the

system from

the

storage tanks and

the sum of

the

meter readings.

meters must have been previously determined.

The usage r a t e can be estimated

t o

determine

whether

Zones can

be

further subdivided depending upon

the

exis t ing

This

type

of

zone

measurement can

be

used in pressure zones

where there

ar e only

a

f e w customers

Each s to ra ge tank i s

Rfter a period of time,

The

pot ent ial leakage

is the

With

t h i s

method, the accuracy of customer

Normal Course of Operation

This

method involves discovering leaks acc identa l ly i n

the

normal course of

operations and maintenance.

may be discovered during t he exercising of valves.

opportunity

to

check f o r v i s i b l e meter

box

leaks when reading

the meters.

For example, in a valve exercising program leaks

Meter readers have

the

Leaks You Can Expect to Find

Main Line Leaks

Main l i n e lea ks range

from

a

low

of

1

gpm

t o

over

1,000

gpm.

corrosion usually

s t a r t

out small but can grow

t o

very large leaks.

S p l i t s can occur due

t o

excessive pressure, improper in st al la ti on settlem ent,

and overloading.

Leaks due

t o

16.

Excavatlng a

53

gp m leak on an old

st eel main.

17.

Sewlc e laterals are com mon In'metall lc pipes.

This leak was m easured at 2 gpm.

53



Jo in t lea ks can occur due t o corrosion, improper in st al la ti on , improper

materials, or overloading.

Service Line

Leaks

Service l i n e leaks range from a low of 0.5 gpm t o over

15

gpm.

lea ks a re caused by the same fa c tors a s main

l i n e

leaks.

Service

l i n e

Residential Meter Box Leaks

Leaks within the vicinity of the

meter

box range from a low of a fraction

of a gpm t o a high of

10

gpm.

Common examples include l eaks due to:

o

loose spud n u t s on ei ther s ide

of

the meter

o

loose packing nuts

o damaged or broken angle stops

o broken or damaged couplings

o

broken

meters

o

damaged or broken

meter

yokes

18.

Leaks from meter boxes are some-

tim es visib le. Here, leak detection

equipm ent determines whether stand-

ing water is runo ff or leakage.

Residential Customer Leaks

Leaks on the residential customer side

of t h e

sys tem range from a low of a

fracti on of a gpm to a high of 15 gpm.

o

holes or breaks in customer

service

l ines

o inefficient hose bib or shutoff valves

o holes or breaks

i n

interior plumbing l ines

o leakage ins ide plumbing fi xt ur es ( t o i l e t

f i x t u r e

leaks are common)

Common examples include:

54



Valve

Leaks

Leaks i n d is tr ib ut io n system valves range f r m a low

of

a frac ti on of a gpm t o

a high of

500

gpm.

broken valves.

Leaks may s t a r t

i n

system cont ro ls such a s pressure-reducing valves , pressure-

sustaining valves, pressure-relief valves, a lt it ud e control valves, blowoffs,

air-release valves, and others.

Common

examples include leaks due t o l oose packing and

Miscellaneous

Leaks

Breaks from excessive pressure, settlement, overloading, improper installation,

improper mater ials, and improper operat ion may occur.

19.

improp er repair

of

hydrant lateral

caused this leak to occur mo nths alter

inlt lai repairs.

20.

Transmission m alniine leak un der this

reservoir was detected by introducing

pressu rlzad air Into the main.

55



CHAPTER 4. CONDUCTING A LEAK DETECTION SURVEY

Leak det ect i on

i s

a process of el i mnat i on and di scovery.

el i mnate t he cont act poi nt s where l eak sounds are not heard and di scover t he

cont act poi nt s wher e l eaks can be heard.

The goal i s t o

Preparing for the Leak Detection Survey

Pr eS ur ve y Review

Pr i or to conduct i ng a l eak detect i on sur vey, you shoul d revi ew t he speci f i cs of

your di st r i but i on system

o

o mai ns and ser vi ces -- t ypes of pi pe, ages, di amet er s, j oi nt s, i nstal l at i on

The fol l ow ng i nf ormat i on i s i mport ant to revi ew:

resul t s of t he water audi t

--

How much wat er i s l ost f romthe system?

met hods, i nspect i ons, l eak hi st ori es, and operat i ng pressures.

types of i nst al l at i ons, meter shut of f s, coupl i ngs, and meter readi ng

f requency.

o

val ves -- l ocat i ons, t ypes of val ves, l ef t or r i ght handed, number of turns

t o exerci se val ves, and how of t en exerci sed.

o hydrant s -- t ypes, si zes, l ocat i ons, f l ushi ng f r equenci es, and unmetered

usage.

pressure- reduci ng val ves, pressure- sustai ni ng val ves, pressure- rel i ef val ves

-- l ocat i ons and how of t en they are exerci sed.

o

bl owof f s and ai r r el ease val ves

--

l ocati ons and how of t en they are

exerci sed.

o di st r i but i on syst emmaps

--

What i s shown on maps, how current i s t he

i nf ormat i on, and how of t en i s t he i nf ormat i on updated?

o meters and meter box assembl i es -- t ypes, br ands, and si zes of met er s, ages,

o

Leak Detection Equipment

Pr ovi de leaic detect i on equi pment f or cr ew members i ncl udi ng soni c l i st eni ng

equi pnent w t h a hi gh f requency l i st eni ng probe and a l ow f requency ground

mcrophone f or pi npoi nt i ng l eaks,

manuf acturers i s i n Appendi x

J

( page 125).

Provi de saf ety equi pment f or cr ew members i ncl udi ng:

o

saf ety vest s

o

t raf f i c cones

o barr i cades

A

l i st of l eak det ect i on equi pment

57



Pr ovi de t ool s t o measure f l ow r at es i ncl udi ng a:

o

st opwatch

o

bucket

o measuri ng cup

o

pressure gauge

o measur i ng t ape or a rul er

Provi de worki ng t ool s, such as:

o meter box l i d l i f t er s

o val ve cover l i f t er s

o

val ve keys

o curb st op keys

o smal l bai l i ng cans or smal l manual pumps

o chal k ( keel ) or spray pai nt

o pi pe l ocat or s

o wrenches f or t i ght eni ng meter spud nut s

Selecting Team Members

When sel ect i ng t eammembers consi der t he f ol l ow ng qual i t i es:

o keen sense of hear i ng

o abi l i t y to di scern di f f erent sounds

o

f am l i ar i t y w t h water met er s and the di st r i but i on system

o sense of r esponsi bi l i t y

o

abi l i t y t o est i mat e l eak f l ows

o abi l i t y to compl et e l eak f or ms

o

abi l i t y t o work on thei r own

Planning the Survey

When pl anni ng how the l eak survey w l l be conducted consi der t he f ol l ow ng:

o What t ype of noi se probl ems exi st w t hi n t he system?

o '&a ef f ect w l l t raf f i c have on t he survey?

o What t ype of prot ect i on i s requi red for t he l eak crew?

o

*&at t i me of day or ni ght w l l be most ef f ect i ve to conduct t he l i st eni ng

survey?

o

What t i me w l l be most ef f ect i ve t o pi npoi nt suspected l eaks?

o

I s

t he cr ew a compat i bl e group t hat w l l work t ogether?

o How w l l t he crew s t asks be di vi ded?

o

What i s t he most ef f ect i ve r out e t o f ol l ow i n t he i ni t i al l i steni ng survey?

o Whi ch ar e t he most ef f ect i ve l eak survey and pi npoi nt i ng f orms and how are

t hese records to be compl eted?

o

How w l l l eak detect i on cr ews communi cate and work w t h repai r cr ews to

ensure ef f ect i veness and r esol ve dry hol es?

Leak Detection & Repair Plan

Prepare a Leak Detecti on and Repai r Pl an.

pages;

a

sampl e pl an i s i ncl uded

i n

Appendi x A.

Appendi x

'L

( page

127).

A pl an

i s

shown on the f ol l ow ng

Bl ank f or m are l ocat ed i n



EXAMPLE

19

LEAK DETECTION AND REPAIR PLA N

WORKSHEET

Name

of

Agency:

XYZ

County

_ I_

a t e r D i s t r i c t

-

Date: 7/18/85

-

A. Area to be Surveyed

1.

2.

3.

4.

Using the

results of

t h e water audit, show

on

a map which areas

in the dis t r ibut i on system w i l l be surveyed.

are as have th e higher pot ent ial fo r recoverable leakage.

Describe each area under B-2. (Items

t o

consider include records

of

previous leak s, type of pipe, age of pipe, s o i l conditions,

high pressures, ground sett lem ent , and improper i ns ta ll at io n

procedures. )

Total miles of main to be surveyed:

I_

46

.

I f

less

than the

to ta l system i s being surveyed, th e calc ula tio ns fo r th e

benefit :cost r a t io must ref le c t t he reduction.

the miles

of

main, include the t o t a l l ength

of

pipe and exclude

serv ice lines.)

Average number

of miles of

main surveyed per day:

In di cat e which

(When calculating

2.0

Explain

i f more

than

3 miles

per day are surveyed.

survey

crew

can survey about two

miles

of main per day.

consider include d is tan ces between

services,

t r a f f i c and sa fe ty

conditions, and number of listening contact points.)

(The average

Items t o

Number of working days needed t o complete survey:

73

(Divide Line 2 by Line 3.)

B. Procedures an d Equipment

1.

Describe the equipment and procedure you

w i l l

use t o detect leaks.

Experience has shown t h a t t he be st r e s u l t s have been obtained by

l i s t en ing f o r l e aks a t a l l system

I_

ontact points

(such

a s water

meters, valves, hydrants, and blowoffs).

Purchase H e a t h S o x i- K it . A tt e n d Manufacturers Seminars and_----

DWR Train ing .

-

o n d u c t i n i t i a l_ i s t e n i n g su r ve y on-l l c on ta c t

_-__

_- ___

o i n t s .

59



EXAMPLE 19 (ant . )

LEAK DETECTION

&

REPAIR PLAN WORKSHEET

2.

3.

4.

5.

6 .

Describe why the areas noted on the map (A-1) have tine greatest

potential for recovering leakage.

Ar ea 1 - Downt own - ol d duct i l e i r on mai ns

Ar ea 2 - St eel mai ns over 40 years ol d

Ar ea 3 - R~~~kder of wt * m

If you w i l l not be l is ten ing for leaks a t a l l system contact

points, describe your plan for effectively detecting leaks.

Not aDDl i Cabl e - crew wi l l 1

Describe

the

equipment and procedure you w i l l use to pinpoint the

exact locati on of tn e detected leaks.

W l l use l ow f r equency gr ound m cr ophone to l i st en over

pavement sur f aces. Consul t ant s cor r el at or wi l l be used i n

di f f i cul t s i t uat i ons.

Describe how the leak detection team and the leak repair crew

w i l l work together. How will they resolve t he problem of dry

holes.

The l eak det ect i on cr ew and t he r eDai r cr ew wi l l i oi nt l y

evcavat e al l l eaks

f o r

t he f i r s t

3

weeks and r esol ve and dry

hol es t her eaf t er .

Describe

the

methods you w i l l use t o determine the flow ra te s fo r

excavated leaks of various sizes.

Bucket and st opwat ch met hod wi l l be used on smal l l eaks.

l ar ger l eaks t he di ameter

of

t he hol e and t he pr essur e wi l l be

measured and used i n t he Gr eel ey f or mul a as shown i n t he Gui debook.

For



EXAMPLE

19

(cont.)

LEAK DETECTION & REPAIR PLAN W ORKSHEET

C. Staffing

1. How many agency st af f w l l be used? 2

St af f Cost s I ncl udi ng Wages and Benef i t s:

Person 1 $/ hour

17 .19

-

$/ day 137.52

Person 2 $/ hour

12 .50 $/ day 100.00

TOTAL $/hour

29 .69

-_

$/ day 237.52

2. H o w many consul t ant st af f w l l be used? 1

Cost of Consul t ant Staf f :

Per son 1 $/ hour 31 .25 $/ day 2 5 0 . 0 0

Person 2 $/ hour

-

$/ day 0

TOTAL $/hour 31 .25 I/ day -____50.00

D. Leak Detection Survey Costs

Leak Detect i on Surveys: $/ day # Days Cost

1.

Agency Crew Cost s

237.5 2 73 $17,340

$ 3,750

. Consul t ant Crew Cost s 2 5 0 . 0 0

175

___I _

5

3. Vehi cl e Cost s 2.40 73

4. Other

d

-

$- --

5. TOTAL Survey Cost s $21,265

E. Leak Detection Budget

1.

2. Leak Det ect i on Team Trai ni ng

3. Leak Detect i on Survey Cost s

4. TOTAL Leak Detect i on Costs

Cost of Leak Detect i on Equi pment

$

2,550

$-

400

$21,265

$24,215

-___

61



EXAMPLE

19

(cont.)

LEAK DETECTION & REPAIR PLAN WORKSH EET

E

Leak Survey and Repair Schedule

I ndi cat e r eal i st i c, pract i cal dates.

1. When w l l t he l eak survey begi n? August 1, 1986

2. When w l l t he l eak survey be compl eted? December 15, 1985

3. When w l l l eak repai r s begi n? August 15, 1985

4. When w l l l eak repai r s be compl eted? January 10, 1986

Prepared

by:

C. M. Biggs 7 / 1 8 / 8 5

Name Dat e

Ti t l e

Mlnl”=r

Team Training

Trai n t eammembers pri or t o conduct i ng a l eak detect i on survey.

opt i ons ar e avai l abl e:

o

Attend manuf act urers’ t rai ni ng semnars.

o

o

o

o

The f ol l ow ng

Have manuf act urers i ncl ude on- the- j ob t rai ni ng when purchasi ng equi pment .

Obtai n on- the- j ob t rai ni ng f romother agenci es w th exi st i ng programs.

Obtai n t rai ni ng f rom

a

consul tant .

Obtai n t rai ni ng f romt he DWR Di st r i ct i n

your

area.

22.

On-the-job training

for

ieak-

detection crews b uilds con fidence.



Equipment Tuneup

Leak detect i on equi pment must be operati ng properl y for

a

successf ul survey.

Pr i or t o conducti ng t he sur vey, l eak detecti on st af f shoul d f am l i ar i ze them

sel ves w th t he equi pment .

i nstr uct i ons.

o

Do

t he bat t er i es need t o be charged or repl aced? (Br i ng extra bat ter i es. )

o Are al l el ect r i cal and physi cal connect i ons ti ght ?

o Are al l cont r ol s worki ng proper l y?

o Check to see i f you can hear t he basi c l eak sound by t est i ng t he equi pment

on

a

hose bi b w t h water runni ng and t hen w th no water runni ng.

Consul t t he i nst ruct i on manual and revi ew t he

Check t he equi pment f or t he f ol l ow ng i tems:

Pr act i ce w t h t he equi pment you w l l be usi ng t o det ect l eaks.

l i st eni ng and di scerni ng t he di f f er ences i n sounds by det ermni ng the f ol l ow ng

f actor s

:

o

t he uni que background sound of your i nst rument

o

what a qui et sound i s ( when no l eak or water use i s present )

o

what water use sounds l i ke by openi ng a hose bi b on

a

customer ' s servi ce l i ne

o

what t he sound i s when a f aucet i s dr i ppi ng

o

what the sound i s when spri nkl ers are i n use i n t he area

o

what the sound i s when the meter i s turni ng

Pr act i ce

Leak D etection Procedures

Initial L istening Survey

The obj ect i ve of t he i ni t i al l i steni ng survey i s to l i sten f or l eak sounds on

al l contact poi nt s i n t he di st r i but i on system

m cr ophone and l i st en f or l eak sounds on al l wat er met er s, val ves, hydr ant s,

bl owof f s, ai r r el ease val ves,

and other contact poi nts. Not e the addr ess of

al l l ocat i ons wher e water use, meter sounds, or possi bl e l eak sounds exi st .

Thi s par t of t he survey i s t he i ni t i al search through each area of t he system

and can be conduct ed qui ckl y.

Use

t he hi gh- f requency cont act

23. Listening o n all valves and ail other

contact points In the dlstr ibu tlon

sys-

tem

Is

imp ortant to an effective sur-

vey.



Nonmet al l i c mai ns r equi r e ext ra ef f ort i n l i st eni ng surveys. I t may be

necessary t o l i st en over t he mai n w th the ground mcrophone t o det ect l eak

sounds. Thi s i s dependent on syst empressure, pi pe di ameter , and equi pment

sensi t i vi ty.

nonmet al l i c mai ns

(

Asbest os/ Concret e or pl ast i c), use t he ground m cr ophone

and l i st en over t he mai n. Have

a

teammember turn on

a

hose bi b at t he

cust omer ‘ s servi ce.

sound

of

water escapi ng f romt he hose

bi b.

mcrophone and l i st en over t he mai n.

greater than t he di st ance that t he sound t r avel s al ong the mai n, t hen you

shoul d use the ground mcr ophone and l i st en over t he mai n at appropr i ate

i nt er val s

(10

t o 25 or

50

feet).

Problems Encountered with the Listening Pracedures

To det er m ne whether t he systemr equi r es l i steni ng over

Determ ne over what di st ance al ong the mai n you hear t he

You may not have t o use t he ground

I f t he di st ance bet ween contact poi nt s i s

Sounds f rom- Cust omer Use I nsi de a Dwel l i ng.

Exampl es of such sounds are:

s ho wKt oi l et s , pumps, met er s, and conversat i ons.

Sounds f romOut si de

a

Dwel l i ng.

w nd and rai n, st r eet craf f i c, i nt er f er ence f rompower l i nes or t r ansf or mer s,

r adi o br oadcast i ng, or l awn wat er i ng,

Some of t hese sounds come f romai r cr af t ,

--ounds f romWater Noi ses.

val ves, or t urbul ence.

These sounds usual l y come f romadj acent l eaks,

Other Probl ems.

equi pment ( l oose el ect r i cal connecti ons) , :

Some other probl ems that may be encountered are f aul t y

i mproper t r ai ni ng, or systempressure

l ess t han 15 Psi .

WATER

ADDRESS

CITY

DATE

TIME

East Bay Municipal Utility District is “listening” to

its

water mains and service connections with electronic leak

detection equipment. As part of this survey, customer

house plumbing systems are “listened to” at the meter.

The detectors have picked up the sound of running water

on your plumbing system, which could mean that you

have leaks in your plumbing. In order to conserve water

and to prevent high water bills, please check your house

for leaks or running water, using the checklist on the

reverse side of this card.

c-93 11175

3. Doorhanger notifying residential customer of p ossib le

plum bing leaks.



Relistening to Suspect Sounds

Return

t o each of

the

locations noted

i n

the

in i t i a l l i s ten ing survey.

the high frequency contact microphone, relisten fo r t h e sounds you heard

e a r l i e r . I f

the

location

is

quie t ,

i t is

not a leak.

If

you s t i l l hear

sounds,

i s t h e

meter running?

Using

If

you s t i l l hear

sounds

when there

is no

water

____

exists. _____

his leak mus t

bT

24.

Re-listening to suspect sounds heaid

on the init ial survey confirms the

sound of a leak or a water-use

sound.

Pinpointing Leaks

The

objectives of pinpointing leaks are ( 1 ) t o determine whether the leak sound

i s leakage, water use, or sane other noise; and

(2) f

it is a leak sound,

determine the lea k' s exact location.

Return t o th e suspected l ocat ion and again l i s t e n f or t he sound.

leak sound?

a l l resources available--naked ea rs , eyes, a sonic amplifier--and walk around

the

area.

pressure reducing valve or electrical transformer.

Review detailed distribution

system

maps and lo ca te pressure reducers,

forgotten valves, or other system apparatus which might make the suspect

sound.

located any suspicious cu lp ri ts , can they

be i d en t i f i ed

and isolated?

example, a customer pressure-reducing valve can

be

isolated by shutting off

the

customer service and bleeding the pressure off

the

system by opening

t h e

customer's hose

bib.

Be sure_ o check with the customer before shutting off

the service

Do

you hear a

If you s t i l l hear a suspect sound,

i t

might not

be

a leak.

The

sound may be from something ot her than a leak, such as a

Use

Check the immediate vicinity and look for suspicious causes. If you

For

6 5



25. Listening on both sides

of

the meter

for the loud est sou nd determines

whether a leak is on th e ut i l i ty “ s ide”

or

the customer’s “ side.”

If the leak noise is heard on a water meter, determine

i f

the sound

is

louder

on

the

customer

s ide or

the agency

s ide of

the meter. Look for obvious signs

of customer use.

may

be

heard turning even i f

t h e

meter hand is not moving.

indicator for movement.

ca re fu l ly

for

leak sounds on both sides

of the meter. If

you are s t i l l

uncertain, you can contact the customer and notify him that you w i l l be

shut t ing

off

h i s se rv ice for a few minutes.

off

system pre ssu re from

the

customer by opening the

hose

bib.

sound quits,

the

leak

is

within

the

meter box, on

the

customer’s servi ce li ne ,

or i n t h e dwelling.

agency side of

the

meter.

If a leak is determined to

be

on the customer

s i d e

of the meter, leave a

doorhanger (such a s tine one shown

below)

notifying

t h e

customer that they might

have a leak in their servi ce l i ne , in te ri or plumbing, or water using fixtures.

Perhaps sprinklers are operating.

I n

t h i s

case , t h e meter

Check

the meter

The leak may be i n the area of the

meter

box.

Listen

Close

the

angle stop and bleed

If t h e leak

If the noise continues,

i t indicates

the

leak i s on

the

26. A

doorhanger notif ies a customer that

leakage s suspected on his side

of

th e meter.

6



If the leak is on

the

main or the se rv i ce l i ne , t h e leak sound may

be

detect-

ab le on adjacent s erv ice meters, valves, or hydrants.

L i s t e n for

sounds of

leakage on serv ice s adjacent t o

t h e

suspected meter and determine where t he

sound is

t h e

loudest.

Pinpointing the exact location can be accomplished by

using

the

ground microphone method

or

using

the

corre la tor method.

Ground Microphone

_I_

ethod.

the locat ion of the loudest leak sound over the main or se rv ice l i n e (p ipe).

The object ive of using t h i s

method i s

t o f ind

-

The f i rs t

s t ep is t o determine

electronic pipe

locator can

be

Precisely mark the location of

Locate other nearby pipes from

the exact location

of the

main

or

se rv ice. An

used t o lo ca te th e buried main or se rv i ce l i ne .

t he

main

or

service line on the pavement.

which

the sound might be coming.

27.

Effectlve plnpoln tlng requlres the use

of p ipe locaters to determ lne the exact

locatlon of undergrou nd plpes.

Ground microphones a r e either monophonic or stereophonic, depending upon t h e

manufacturer.

i n t ens i ty between two microphones.

microphone.

The

s t e reo models have the capabi l i ty t o discern differences in

However,

most

models have only one

28.

If he location of pipes Is known, a

ground mlcrophone wl l l help pinpoint

the locatlon

of

leaks.



When usi ng the ground m cr ophone f or pi npoi nt i ng, r emember t o set t he vol ume

rel at i vel y l ow at the begi nni ng, so l oud sounds w l l not be uncomor tabl e.

Keep t he vol ume adj ust ment at t he same l evel t hroughout each pi npoi nt i ng

sequence.

saf et y, then resurvey t he poi nt s t o l ocat e t he l oudest l eakage sounds.

Use the ground mcrophone and l i st en f or l eak sounds every

5

t o

10

f eet and

wr i t e not es on the sound i ntensi t i es.

t he meter r eadi ngs down.

of t he l eak. Be car ef ul NOT t o change t he sett i ng of t he vol ume or other

cont rol s dur i ng thi s process. Wher e possi bl e, avoi d compar i ng sounds f rom

poi nt s w t h di f f er ent sur f ace and compact i on charact er i st i cs. I f t hi s i s

unavoi dabl e, make al l owance f or t'ne fact that t he same l eak sound w l l be

qui et er f rom

a

l oosel y compact ed sur f ace t han

a

dense one.

The ground m cr ophone process shoul d be repeated t o ver i f y t he l eak l ocat i on.

I f uncom or t abl y l oud sounds are hear d, r educe t he vol ume f or your

I f t he equi pment has

a

met er , wr i t e

The st rongest si gnal usual l y i ndi cates the l ocat i on

29.

Geophones enable l istening In stereo.

Correl ator Method.

used t o pi npoi nt l eaks whi ch usual l y i ncl udes t he fol l ow ng i tems:

o

o

o

o

a m crocomput er

o

o

a

cat hode ray tube ( CRT) vi deo di spl ay

o

o

A cor rel at or i s a package of el ect roni c equi pment

t r ansducers ( t wo or more) whi ch pi ck up the noi se f romt he pi pe and conver t

i t i nto an el ect roni c si gnal

t wo set s of cabl es or r adi o t ransmt t ers/ recei vers t o car ry t he el ectr oni c

si gnal f rom the t r ansducer s to t he correl ator

ampl i f i ers and a correl at or whi ch compare t he si gnal s recei ved f romt wo or

more si gnal sour ces

a speaker (and headphones) t o recreat e t he l eak sound f or t he operator

a paper t ape pr i nt er , on some model s, t o provi de a permanent wr i t ten di spl ay

of t he l eak wave f orm and t he di st ance of t he l eak f romt he cont act poi nts

a

power suppl y ( of ten a 12- vol t aut omobi l e bat tery)



CORRELATOR METHOD

Som e com elators have a pap er tape, along with a

CRT.

for permanent records

of

a leak.

Prospect i ve users of cor r el at or s shoul d be advi sed t hat cor rel at or s are compl ex

el ectroni c equi pment that r equi r e consi derabl e t rai ni ng f or successf ul use.

Corr el ator s are not desi gned t o be car r i ed by hand.

pounds and need an el ect r i c power suppl y.

some model s may be used for soni c l eak detect i on when handl ed caref ul l y.

They wei gh f rom25 t o 50

The t ransducers/ t ransmt t er uni t s of

69



***

RUN

***

tmrmsl

C ~ I

m GP 1.28

3.7

B C I P

75-1.28

15.2

1 P 1 . 2 8 5 . 6

4

R

6:

7.77

Td= -7.6 Cmsl

R:

16.73 Cml

01

6

5 ,

vz:

2

MEM.

31. TLplcal paper tape outp ut of l eak ioca-

t ion. The spike on the chart locates

the

posl t lon

of

the l eak between ¶he

blue an d red transducers.

D A T E

NO.

After

confirming that the ame leak sound i s

s t i l l

present and can be detected

from _.

wo

separ ate contact points, the cor rela tor may be

u s e d .

The

pipe locations and configurations must be determined even more accurately

than

they were i n the

sonic equipment method.

__

etween the

contact

points

must be ca re fu ll y measured in the

f i e l d

(including

th e depth from surface t o main) and t h i s information i s

fed

i n to t h e computer.

Pipe s i ze and materia l type is al so input t o th e computer.

Two elect roni call y amplified transducers a re attached t o separate contact

points

on

each

s ide

of

the

detected leak.

The

distance

-

long the pipe

The operator must take great care

t h a t

t h e

transducers are identified

with

the co rr ec t color-coded contact

points.

Otherwise, t he

distance t o the leak

w i l l be

measured from t h e wrong

contact point resulting

i n

a dry hole.

32.

A

transducer detects the leak sound,

which is transm itted b y a po rtable

transm itter to the correlator. Pinpoint-

in g a leak requires

two

l istening

points that span th e leak.



The cor rel at or computor senses the l eak noi se, t hen cal cul ates t he di st ance

f romt he l eak t o each t ransducer .

di spl ay or pr i nt ed on paper tape.

The operator t hen measures the i ndi cated di st ance f romone of t he cont act

poi nt s to f i nd t he l eak l ocat i on. A wort hwhi l e check i s t o r emeasure the

di st ances f rombot h cont act poi nt s t o be sure t he i ni t i al measurements are

corr ect . )

Af ter pi npoi nt i ng t he l eak usi ng ei ther met hod, mark t he pavement above t he

exact l ocat i on of t he l eak.

turn i n work or ders f or repai r .

Pr obe Method.

t wo previ ous met hods i s t o dr i l l a smal l hol e t hrough the pavement over t he

suspected l eak l ocat i on.

t ake car e not t o damage t he pi pe.

a

met al rod w t h

a

T handl e caref ul l y i nto t he hol e and use the hi gh-

f requency soni c m cr ophone to l i st en agai n f or t he sound of l eakage.

t o f i r st check f or other ut i l i t i es. Addi t i onal hol es may be dr i l l ed as

necessary.

The r esul t s ar e di spl ayed on the CRT vi deo

Log al l i nf ormat i on on the l eak detect i on l og and

An addi t i onal pr ocedur e t o f ol l ow when usi ng ei ther of t he

When dr i l l i ng hol es i n t he pavement over t he mai n,

Water may surf ace t hrough t he hol e.

I nser t

Remember

33. In unpaved areas, a probe can b e

us ed as an extension t o l is tening

direct ly o n

the

burled pipe.

71



To assure that you w i l l not be a f fec ti n g o th er u t i l i t i e s ,

before

digging,

contact Underground Service Alert (USA), a locat ion service, at :

o

800)422-4133 for

t he

Southern California counties

of

Imperial, Inyo, Los

Angeles, Orange, Riverside, San Bernardino, San Diego, Santa Barbara and

Ventura.

(800) 642-2444 fo r a l l other Californi a counties plus

the

State of Nevada.

Excavating the Leak.

th e repa ir crew should work toge ther t o uncover th e leak.

the survey crew can re li st en t o

the

sound and assist the repair crew in

locat ing

the

leak.

t he

pipe or a

few

inches away and no sign of dampness or water

is

v i s ib l e .

working together, both the survey and repair

crews

can share knowledge and

experience that make locat ing

the

leak easier.

When excavating the leak, both the survey crew and

If

the

hole is d r y ,

Leaks may

be

missed because the leak is on the bottom of

By

34.

Uncovering leaks requires caref

excavation to avoid oth er pipes,

util it ies,

or

both.

u l

other

,

2



Leak Detecti on-.

The f ol l ow ng t i ps may be of assi st ance when

conduct i ng tine l eak survey and pi npoi nt i ng t he l ocat i ons of l eaks.

o

Many agenci es syst emati cal l y survey areas out l i ned on maps.

meter reader r out es

as

they have been wel l t hought out and mni mze t he

di st ances i n cover i ng t he system

Ot hers f ol l ow

Greater f aml i ar i t y w th t he system

l ayout i s needed to ef f ect i vel y cover t he meter readi ng routes.

Exerclslng the h ydrant valve

helps pin point a leak.

o When usi ng the ground mcr ophone i n t urf areas t he use of a thumb tack

assi sts i n get t i ng bet ter sounds.

pl ate at tached

t o

a st r ong, met al , ver t i cl e spi ke.

of soni c l eak detecti on equi pment have i nf ormati on on thumb tacks .

A thumb tack i s a f l at , met al , hor i zont al

The manuf acturers

o

Some agenci es concentr ate on t he l i st eni ng phase f or several days and

pi npoi nt at t he end of t he week.

Except when saf et y i s

a

consi der at i on,

a

one- person cr ew i s ef f ect i ve f or

conduct i ng the l i st eni ng survey.

o

o

Leak Detect i on Sur vey Dai l y Log, as shown i n Exampl e 20 ( Page 74), can

6e used f or t he i ni t i al l eak det ecti on survey.

Bl ank f orms are l ocat ed i n

Appendi x

K

( page 127).

73



Measuring and Estimating Losses from Discovered

Leaks

Losses from leak s th at a re discovered and rep aired should be measured t o

determine the rate of loss and the total volume lost during the l i f e of the

leak.

Douglas S. Greeley

i n

Water Emergency and_-Management Reference Number 1981):

o

Use

a containe r of known volume and a s top watch.

o Use a hose and a meter.

o

Calculate los ses using modified o ri f ic e and f ri ct io n loss formulas.

Three methods a r e suggested (from "Leak Detection Produc tivi ty ," by

36.

Service-ilne leaks can be easily

repaired b y replacing a part of the

service h e . Some agencies p lace the

damaged llne in l i ne with a test meter

and m easure the flow rate.

The f i r s t method, sometimes known a s th e bucket and s top watch method, i s a s

simple as

i t s

name.

Hold a container against the leak for a predetermined

time

period.

the time with a st op watch.

other container of known volume.

minute.

Use time interv als tha t are easy t o deal wi th.

Time in seconds:

6

10

15

30

Multiply volume i n gallons by: 1 0 6 4 2

t o g et gallons per minute.

f ie

conversion fac to r t o calcu lat e acre-feet for a two year

time

period, from

gallons per minute (gpm) :

Measure

Measure the water captured

with

a measuring cup or

Then convert time and volume t o gal lons per

60

_min/hr)(24 hrs/day)(365 days/fi2 ____ears) = 3.23

325,828 gallons per acre-foot

1.0

gpm fo r 2 yea rs = 3.23 ac re -fee t over t h e two-year average leak

lifetime.

Large spraying-type le ak s can be measured by drap ing an enveloping device (such

75



a s

a large

canvas, rain

jacket, or

lar ge inverted pa il ) over

the

leak and

divert i ng th e water int o a container.

The second method r eq ui re s connecting a hose t o the leak and dir ecti ng the

flow

through a meter.

The

t h i r d

method is the simplest

t o

perform in the field but requires

calculations.

to o g re at t o measure and the main must be valved off.

I t

requi res tha t the

s i z e and shape

of

t h e

hole

be measured and t h e li n e pre ssu re be determined.

pressure gauge or a hand-held

blade

pitotmeter could be used t o determine t h e

pressure of t h e water coming from the lea k o r a nearby f i r e hydrant.

method al so us es some assumptions regarding the shape of t h e hole which may

introduce error.

For losses from such items a s pipes o r broken t ap s, Greeley assumes an orif ice

coefficient of

0.80 and calculates flow in gallons per minute from t h e formula:

Q

=

(43,767/1440)

x

A

x

square root

of

P

I I~

his method

i s

often helpful for large leaks

where

the

flow

is

A

This

where

Q =

flow i n ga llo ns per minute

A

= t h e cross sectional area of the leak in square inches and

P = t h e pre ssur e i n pounds per square inch.

For example,

i f

t

e

hole in t he p ipe were roughly circular, then the area would

be:

ascer ta in

the

pressure in the pipe.

For re la t ively small holes, the following leak rates in gallons per minute

(Table 5 ) were calc ulat ed, assuming a ci rc ul ar hol e and s ever al pressures.

9

A

= 3.14 x r .

You need only measure the diameter of th e hole and



Calculating Leak R ates for Small Leaks

The following tables provide leak rates for typical meter box leaks.

These tables can be used t o convert dr ip s per second and cups per minute t o

gallons per

minute

t o be entered on

the

Leak Repair Report.

TABLE

4

LEAK LO SSES FOR CIRCULAR HOLES UNDER DIFFERENT PRESSURES

20 40 60 80 100 120 140 160

0.070

25

180

200

0.196

0.384

6

o 0.785

0.950

A R E A

I 20 -0

-

0

-

0 -00 -20 140

L E N G T H

7

9

1.767

1

180 200

-

60

-

2.270

2.545

2.836

o 3.142

1.061 1.510

1.850 2.136

2.388

4.271

6.041

7.399 8.544

9.522

9.611

13.593

16.648 19.224

21.493

17.081

24.165

29.597

34.115 38.209

26.699 37.158

38.471 54.372

52.331 74.007

68.350 96.662

86.506 122.338

106 .I98 151.035

129.225 182.152

153.789 217.490

46.245

53.399 59.702

66.593 16.894

85.911

118.387

136.101 152.840

90.640 104.662 iii.nio

149.833 173.012 193.434

184.979

213.596 238.807

223.825 258.451 288.951

266.310

307.578 343 2382

180.488

255.249

312.615

360.971 403.584

209.324

296.028

362.559

418.648 468.062

240.295

339.829 416.203

480.590 531.317

273.402

386.649

473.547 546.805

611.347

308.646 436.491

346.025 489.353

385.540 545.231

427.991 604.140

534.590 617.292 690.153

599.333 692.050 173.136

661.716

771.081 862.095

739.9 18 854.383 955.230

2.616 2.825

10.464 11.302

27.544 25.470

.

4i .a56 45 .zag

65.400 10.640

94.176 101 .I21

128.184 138.454

167.424 180.839

21 .896 228.874

261.600 282.561

316.536 341.898

376.704 406.887

442.104 411.527

512.731 553.819

588.601 675.162

66i.691 63.355

756.025 816.600

847.585 915.496

944.318 1020.040

1046.400 1130.240

3.021 3.204

12.083 12.816

21.186 28.835

48.331 51.263

15.518 80.098

108.745 115.341

148.014 156.993

193.325 205.052

244.676 259.5 19

302.070 320.394

365.505 387.676

434.981 461.361

510.498 541.465

592.051 627.912

619.658 720.886

173.299 820.208

812.983 925.938

978.101 1038.010

1090.470 1156.620

1208.280 1281.570

3.331

13.509

30.395

54.036

84.431

121.581

165.485

216.144

213.551

337.725

408.647

486.323

510.755

661.941

759.880

864.575

976.024

1094.220

1219.180

I350 .890

-

e a bo v e t a b l e

of

lasses f r o m r w g h l y c i r o u l a r s hs pe d h o l e s i n p i p e

is

c o m p u t e d

from

t h e f o l lo w i n g f o r m ul a e s t a b l i s h e d

Q z (30.394)(A)(square r o o t o f P ) g a l l o n s p e r m i n u t e

A i s

t h e

cross

s e c t i o n a l

area

of t h e l e a k i n

square

i n c h e s and

P i s

t h e p r e s s u r e i n p o u nd s p e r s q u a r e i n c h

__

____

TABLE 5

LEAK LOSSES FOR JOINTS AND CRACKS UNDER DIFFERENT PRESSURES

l e a k s e m i t t e d f ro m j o i n t s a nd c r a c ke d serv ice p i p e s an o r i f i c e c o e f f i c i e n t o f 0.60

i s

u s e d i n t h e f o l l o w i n g e q u a t i o n .

Q (22.796)(A)(square r o o t of P)

A is t h e erea

in

s q u a r e i n c h e s a nd P

i s

t h e p r e s s u r e i n p o un ds p e r square i n c h .

f o l lo w i n g t a b l e of f l a v r a t e s was c o m p u t e d i n g a l l o n s p e r m i nu te far f o u r d i f f e r e n t l e a k dimnsions u n d e r P P B S S U P ~ S

from

20

t o 200 p s i .

77



TABLE 6

DRIPS PER SECOND CONVERTED TO GALLONS PER MINUTE

Drips per Second

Gallons per Minute

1

0.006

2 0.012

3 0.018

4 0.024

5

0.030

Note: Five dr ips per second amounts t o a steady stream.

TABLE

7

CUPS PER M INUTE CONVERTED

TO

GALLONS PER MINUTE

%ounce Cups per Minute

Gallons per Minute

0.25

0.50

0.75

1 .oo

1.50

2.00

2.50

3.00

3.50

4.00

0.016

0.031

0.047

0.062

0.094

0.125

0.156

0.188

0.219

0.250

Use the Leak Repair Report Form,

t o record a l l information regarding leak

excavation, flo w ra te s, and leak repair .

(See Example

21

on page 79.)

Determining Leak Detection Effectiveness

An important and often neglected par t of

t h e

leak detection project i s the

determination of whether th e pr oj ec t was a cos t-eff ect ive water conservation

measure.

the agency

must

evaluate the completed

leak

detection project.

To determine whether the leak det ectio n pr oje ct was cost ef fe ct iv e,

The

Leak

includes

Detection and Repair Project Sunwary (see Example 22 on page

81)

information needed fo r t h i s evaluation.



EXAMPLE 21

LEAK REPAIR REPORT

Agency XYZ

Ccuntv Water Distr ict

11

5

85

(Month) (0.~1

M e 4

Date of Repair:

W.O. NO. 10077 Foreman Hal Nielson

Leak Iden tificot ion Map Reference

Refer

to

Leak Discovery Report

D i s c o v e r y b k 11 A A 5 LeakNo.=

Location: (include street mme and number) 9774

r;lra.=n

V i e w

Area 13

Page and Coordinates

1.

2.

3.

4.

5.

For Main and Service Lateral Leaks Only

Sketch

D m p

of the s i h ncluding:

If Moin or Service Leak,

Attach Three Photos:

Street name; north arrow

Meter number ( if ap plicab le)

Mains and hydrants in shutdown area.

A l l

valves, valve numbers and show

Locate leak to nearest inte rsecti on or house with address.

Show distances to property linez or street centerlines.

1.

2.

3.

which were closed during repair.

Straight down over leak

or mge

Close-up of leak and damage

An other photo which

you

feel

w i h help.

Leak Found ?

yes

Y e s h o )

Meter Leak -

Meter Spud Leak

-

Meter Yoke Leak -

Curb Stop Leak -

Domoged port was:

Y

epaired

If repaired, what repoirs were made?

-Leak Clomp

-

epacked valve

~ r b w ire 7 (persons)

-Welded - ecaulked ioint

Equipment Used for Repair

-Other (describe).

-

ackhoe

TYPE OF

LEAK

Main Lin e Leak - Joint Leak -

Service Lateral Leak

-

Other Leak

1L

Fir e Hydrant Leak _. Describe-c

Valve Leak _. Fliiqhi-

DESCRIPTION

OF REPAIR

-

eplaced I f replaced,

what

material was

used?

-

Renair t i m e 4 F r o m

o)

- umptruck

Repoir

Casts:

Size of Leak

Materials $ 11.19 Measured 3 - 1/2 GPM

Labor $ 114.72

Total $ 138.91

Equipment $ 12 - 00

Other $ 1.00

GP%

stimated -

1/2

ga l lon u c k e t

Method u.sed: Timed

with

stop

watch

79



EXAMPLE

21

cont.)

annual water

loss

ra ti o versus sal es has been increasing a t a r at e of

1% which

would

te t ha t a percentage

of

these flushing

l i n e s

were already star t ing to leak

b a c k

i n 1981.

Descr ipt ion of Damage for

Mains

and Services

Type

of

Break

Flange nuts, bolts, t ie rods

-

plit

-

i p

h r r e l

-

Other (describe - ole

- oint

-

In your opinion, what caused the damage?

Whot part was damnged?

Circumferential split

alve

-

Broken coupling

Service pulled

Cracked a t corp. stop

Gasket blown

48

-

rushed pipe

Estima ted age of leak in months

How Determined *See top of page - racked Be l l

Diameter

of

Main

or

lateral in inches

Depth to top of pipe in inches

-

-

-

-

-

-

ther (describe)

Pipe Material:

-

alv.

Iron -

uctile

Iron -

. C.P.

System Pressure

How Determined

teel

-

.V.C.

- lock

Iron -

Cast

Iron

- opper

-

olybutylene

-

Examine broken edge of cost ord uctile iron pipe:

Origianol

of good grey is on:

thickness metal remaining

-

utride

Inches Inches

-

nside

Min. thickness Deterioration

Number of previous leak

s

there evidence of previous leak or

No repair clamps present

Cause of Leak

Y e s

-

epairs in same general area?

La st repair date (i f known)

-

No

-

o not know

n your opinion, should pipe be replaced? - e s -

FOR EXCAVATIONS INDICATE GROUND CONDITIONS

Type of k i l : Exis ting Bedding: Type

of Cover:

-Rocky

-

andy - raveVSand

-

oncrete

-Clay ~ Hard Pan x ative Soil

-

sphalt

-Adobe Loom - ea Gravel - oil

__Other

~

Other

-

ther



EXAMPLE 22

LEAK DETECTION AND REPAIR PROJECT SUMM ARY

Agency: Xk'Z County

Water

D i s t r i c t

Name of Report Preparer:

Date:

November

30, 1985

C . M. B i n n s

Leak Detection Survey

TOTAL Number

of

Days Leak Surveys

were

Conducted: 65

First Survey Date: 7 / 1 0 / 8 5 Last Survey Date: 1 1 / 4 / 8 5

Number of Meters Flydrants Valves

Test

Rods Other

Listening

Points

Used:

13,786 1,067

--

505

0

Number of Suspected

Agency Leaks:

175

Pinpointed

I

Survey Time: Miles of Main Pinpoint ing

Time:

Surveyed: 124.7

-

2 hours

69

hours

--

Average survey rate

Miles

of main surveyed--

8 =

2.1

miles

per day

Total survey and pinpointing hours

TOTAL

number of

visible

leaks reported

since

survey started, from

0

ther

sources

(not discovered during leak detection surveys),

-

Leak Repair Summ ary

Date First Leak

Repair Made: 7 / 1 1 / 8 5 Repair Made: - 1 / 5 / 8 5

Number

of

Repair s Needing Number of Repairs Not

Excavation: 27 Needing Excavation: 148 Repaired Leaks:

-

75

TOTAL TOTAL,

Water Losses from

Water Losses from

Nonex- TOTAL

gater

Excavated Leaks: 203.5 gpm cavated Leaks: 2 .9 gpm Losses: 206.4 pm

Date Last Leak

-

TOTAL Number of

Excavated Leak

Repair Costs

Nonexcavated Leak

Repair Costs

TOTAL

Repair

Costs

Materials

$ 699 .36

Materials

$ 411 .68 Materials $

1 , 1 1 1

114

Labor

$ 4 ,377 .39

Labor $ 2 .255 .72 Labor

Equipment $ 561.4_0

Equipment 248 .75 Equipment $ 810 .50

$

6,633.11

Other $

35 .00

Other

$

83 .50

Other

$

118.50

Subtotal

$

F3- i -375 Subtotal $ 2,999.05 TOTAL $ 8,672.80

81



EXAMPLE 22 (cont.)

LEAK DETECTION AND REPAIR PROJECT SUMMAR Y

Agency: XYZ County Water District

Date: November

3 0 , 1 9 8 5

Leak Detection Project Cost Effectiveness

Step

1.

Cal cul at e the val ue of water recovered

(Vwr)

f romal l repai red

l eaks.

(Vwr) = ( Tot al l eakage recovered i n gpm( Conversi on Factor)(Water cost , Wc)

Conversi on factor = 1 gpm f or

2

years

3.23

acre- f eet

Wc Li ne

19

of Wat er Audi t Repor t

=

wat er pur chase pr i ce

+

operat i ng cost s

per uni t of water

Vwr

= (

-

0 6 . 4

gpm ( 3 . 2 3 acre- f eet / gpm ( E$/ acr e- f eet )

s tep2.

Leak Detect i on Sur vey Cost s

V w r = $ 1 8 3 , 3 3 5

Det er m ne t he t ot al cost of t he l eak detect i on survey.

.........eak Detect i on Equi pment

$ 2 , 4 0 4 . 6 5

-

Leak Detect i on Trai ni ng ..........$ 4 0 0 . 0 0

Leak Detect i on Survey Costs

......

2 5 . 9 4 4 . 8 4

TOTAL COST of Leak Det ect i on Sur vey 2 8 , 7 4 9 . 4 9

Step3.

Di vi de

Vwr

f romSt ep 1 by t he tot al cost s cal cul ated i n St ep

2.

Benef i t : Cost Rat i o (B: C) equal s: Val ue of \ . l ater Recovered

Tot al Cost Leak Detecti on Survey

BC

I

. 4

__

For pl anni ng f ut ur e l eak det ect i on ef f or t s, you can cal cul at e aver age survey

cost s per ml e.

Step4.

Determ ne average survey cost s per ml e of mai n surveyed (C/M.

C/M

Tot al Cost of Leak Detect i on Survey $ 2 8 , 7 4 9 . 0 0

1 2 4 . 7 0

-

ot al Number of M l es Surveyed

M

C/M

=

$

2 3 0 . 6



APPENDIX A

SAMPLE COMPLETED AUDIT REPORT &

LEAK DETECTION AND REPAIR PLAN

This

sample completed Water Audit report was used by

the

California Department

of Water Resources a s an example fo r p ar ti ci pa nt s t o follow in i ts statewide

Leak Detection Grant Program.

conducted water au di ts for a one-year period with emphasis on master and sales

meter accuracy plus unmetered water uses.

No

low-flow zone measurements

were

required, although

Participating water ut i l i t i e s and

dis t r ic t s

i n several instances,

they

might have been useful.

WATER AUDIT REPORT

Prepared by

XYZ

County Water District

This report includes the following items:

o a water audit worksheet

o

uncorrected t o t a l water supply

o adjustments t o to t a l water supply due t o source meter error

o uncorrected total metered water use

o meter tes t r e s u l t s

o

adjustments due to system service

meter

error

o a description of accounting procedures reviewed

o a description of actions taken to determine unmetered uses

o

a descri ptio n of acti ons taken t o determine water l os ses

o a summary of re comendat ions fo r system improvements proposed a s a re s u l t

of th e water a udit

o a leak detection and repair plan

A l l

discussions and tables refer t o t he l ine numbers of

the

Water Audit

Worksheet.

Subm itted by:

C.

M. Biees

Name

7 / 1 8 / 8 5

Date

M a n l

Title



APPENDIX A

Page 2 of

19

WATER AUDIT W ORKSHEET

For the Water District:

LINE ITEM WATER VOLUME U N I T S

1 Uncorrected Total Water Supply

t o t he Distribution System

(Total of Master Meters)

Total

Subtotal Cumulative

11

, 2 7 0 , - Acre-feet

2 Adjustments t o Tota l Water

supply

2A Source

Meter

Error (+ or -1 + 254.5

Acre- fee t

2B

Change

i n

Reservoir and Tank

Acre-feet

__

torage (+ or

-)

+ 2 .5 .

Losses

(+

or

-)

2c Other Contributions or

0 Acre-feet

--

3 TOTAL

Adjustments t o Total

Water Supply (+ or -)

(Add L i n e s

2A, 28,

and 2C.)

+

257.0 Acre-feet

4

ADJUSTED

TOTAL

Water Supplied

t o the Distribution System

(Add Line

1

and

L i n e

3.)

11,527.0

Acre-feet


Water

Use

10,000 Acre-feet

5

6 Adjustments Due t o Meter

Reading Lag Time (+ or

-)

+

0 . 6

7 Subtotal: Metered Deliveries

(Add L i n e s 5 and

6 . )

10,000.6- Acre-feet

8

TOTAL

Sales Meter Error and

System Service

Meter

Errors

__I

04 .1

Acre-feet

(+ or-)

Deliveries (Add

L i n e s

7 & 8 . ) 10,504.7

Acre-feet

Water (Subtract Line 9 from

Line 4.)

9 C O R R EC TED

TOTAL

Metered Water

10

CORRECTED

TOTAL

Unmetered

Acre-feet

* The u n i t s of water measurement must be con si st en t throughout the worksheet.

Their se le ct io n (e.g., acre-f eet, mil lions of gal lons, hundred cubic

feet)

i S

l e f t to t h e user.

____

,022.3

I

4



LINE

1 1

11A

11B

11c

11D

11E

11F

11G

11H

111

l l J

11K

11L

11M

12

APPENDIX A

WATER VOLUME UNITS*

Total

Page 3

of

19

Subtotal Cumulative

Author i zed Unmetered Water Uses

ITEM

Fi ref i ght i ng &

Fi r ef i ght i ng Trai ni ng 30.

5 .

Mai n Fl ushi ng -

I _

t ormDrai n Fl ushi ng 1 .5

Sewer Cl eani ng

2 .

St reet Cl eani ng

5 . 4

School s 0

Landscapi ng i n Large Publ i c Areas

Parks 140.

Gol f Courses 3 7 0 .

Cemeteri es 12.

Pl aygr ounds

19.

Hi ghway Medi an St r i ps

2 .

Ot her Landscapi ng 1 .

Decor at i ve Wat er Faci l i t i es

0 metered

-

0 metered

0 metered

Sw mni ng Pool s

-- --

Const ruct i on Si t es __

Water Qual i t y and Ot her Test i ng

( pr essur e t est i ng pi pe, water

Process Water at Treat ment

Pl ant s 0 . 2

Other Unmetered Uses

TOTAL Authori zed Unmetered

Water (Add Li nes

11A

t hr ough 11M )

0 metered

qual i t y, etc. )

-

-

0

__--

-

cre-feet

-cre-feet

Acre-feet

*

Acre-feet

Acre-f e-

Acre-feet

Acre-feet

A c r e - f e e L

-

cre-feet

Acre-feet

Acre-feet

A c r e - f e e e

Acre-feet

Acre-feet

Acre-feet

A c r e - f e e t

588.1 Acre-feet

-

as



APPENDIX A

LINE ITEM

Page 4 of

19

13

14

14A

1 4 8

14C

14D

14E

14F

14G

14H

15

16

17

18

18A

18B

19

WATER

VOLUME

Total

Subtotal Cumulative

TOTAL Water Losses

(Subtract L i n e 12 from

L i n e

10.)

434.2

Iden t i f ied Water Losses

Accounting Procedure Errors

Illegal Connections


System Controls


Leakage

Evaporation

Reservoir Overflow

Discovered Leaks

Theft

TOTAL

Identified Water Losses

(Add Lines 14A through 14H.)

Pdtential Xater System

Leakage (Subtract L i n e

15

from L i n e 13.)

Recoverable Leakage


Cost Savings

35.7

133.9

300.3

225.2

Dollars per Unit of Volume

Cost of Water Supply $ 225lAcre-foot

Variable

0

& Costs

$

- - ~ / & ~ e - f o o t

TOTAL Costs Per U n i t of Recoverable

Leakage (Add

L i n e

18A t o

Line

188.)

$ 275lAcre-foot -

UNITS*

Acre-feet

_--

Acre-feet

--

cre-feet

Acre-feet

-

cre-feet

Acre-feet

Acre-feet

Acre-feet

Acre-feet

Acre-feet

Acre-feet

Acre-feet



Source

1 Source

2

Type of Measuring Device

Identification Number

(may be serial no.)

Frequency of Reading

Type of Recording Register

U n i t s Registers Indicate

Multiplier (if any)

Date of Installation

Size of Conduit

Frequency of Testing

Date of Latest Calibration

Source 3

V e n t u r i

0000278-A

Month

Daily

Dial

100,000

gallons

1

.o

1950

24 inches

Annual

4/1/84

Source Source 2 Source 3

Turnout Well Field City Monthly

41 Intertie

Totals

acre-feet acre-feet acre-feet acre-feet

Propeller

8759

Weekly

Dial

gallons

1

.o

1968

8 inches

2 years

8/21/84

V e n t u r i

OC

-

16

Daily

Builder Type

M

cubic

feet

100.0

1955

11.5

inches

4 months

1/15/85

January

February

March

April

Nay

June

July

August

September

October

November

December

TOTALS

-0-

-0-

-0-

400

815

920

930

1000

900

400

400

400

6, 165

-----

400

600

800

400

300

0

-0-

-0-

100

100

-0-

-0-

2,700

-----

320

200

-0-

-0-

-0-

250

260

275

100

300

400

300

2,405

-----

720

800

800

800

1, 115

1,170

1,190

1,275

1,100

800

800

700

11,270

-----

TOTAL Supply t o th e System

11,270

acre-feet

( En te r e d

on Line

1)



APPENDIX A

Page

8

of 19

Month

UNCORRECTED TOTAL METERED WATER USE

Metered Subtotal

Residential Industrial Commercial Agriculture

( i n

acre-feet)

(i n acre-feet) ( in acre-feet) (i n acre-feet)

( i n

acre-feet)

Jan

Feb

Mar

April

May

June

July .

A%

Sept

Oct

NOV

Dec

Subtotal

450

500

500

800

815

700

500

500

-50

7,115

110

110

110

120

150

150

140

110

110

110

1,500

-

TOTAL

Uncorrected Metered Water

Use

25

25

25

25

25

25

25

25

25

25

25

25

300

-

-0-

0

-0-

75

175

230

175

230

200

0

0

-0-

1,085

-

585

635

635

770

980

1,105

1,150

1,220

1,065

635

635

-85

10,000

10,000

( E n t e r e d

on L i n e

5)

DETAILED METER LAG CORRECTION

The December through January billing period i s 62 days long.

Route Read Date Sales Adjustment

--

A 2/1/54

12 ac-f t 31/62

=

-6.0 ac-ft

B

2/10/84

10 ac-ft 21/62 = -3.4 ac-ft

C

2/20/84

11 ac-ft 11/62

=

-2.0 ac-ft

-11.4 ac-ft

ater

use

................................

A 2/ 1 85

I 3 ac-ft 31/62 6.5 ac-ft

B

21

I

0185

10 ac -ft 21/62 3.4 ac-ft

C 12/20/85

12 ac-f t 11/62 I: 2.1 ac-ft

Water Use

................................

+12.0 ac-ft

+0.6 ac-ft

(Entered on Line 6)



APPENDIX

A

Page

9

of

19

Tot al Vol ume

Sal es at Fl ow Meter Meter Er ror

(ME)

Vol ume Vol ume Bate Regi st rati on ME Vf

-

Vf

BV) (Vt ) (Vf ) R) -

Meter Error

(ME)

( i n ac- f t)

100.0 7,115.0

TOTAL Resi dent i al Meter Error

=

.

412.1

Meter Dat e of

I D

Meter

I nstal l a- Manuf ac-

No.

Si ze

Type

at i on turer

Test Mean Regi st rati on at

Date Var i ous Fl ow Rates

91



APPENDIX A

Pag e 11of 19

Line 11A Firefighting & Firefighting Ita inin g:

The f our f i r e compani es i n the servi ce area do not make

f i ref i ght i ng reports. The f i r e commander r evi ewed thei r l ogs.

They repor t 10 st ructural f i res and a 5- day w l d f i r e (water

ai r l i f t ed fr omopen reservoi r ) pl us

8

days

(48

hours) of t rai ni ng

where water was used.

Water Use Est i mates are:

Fi ref i ght i ng

20

acre-f eet

Tr ai ni ng 10 acre- f eet

TOTAL

........

30

acre- f eet

Line 11B Main Flushing:

Mai ns were f l ushed through r el i ef val ves and hydr ant s on 18

occasi ons (54hour s t otal ) account i ng f or approxi matel y

5

acre-

feet.

Line 11C Storm Drain Flushing:

The County Depar t ment of Wast e Water Treatment est i mates

approxi matel y 1.5 acre- f eet of water used to r el i eve congest ed

st or mdrai ns.

Line 11D Sew er Cleaning:

The County Depart ment

of

Wast e Water Treatment est i mates

approxi matel y 60 days work usi ng j et vactor and rel eases f rom

f i r e hydrant s f or an est i mated

2.0

acre- f eet of water .

Line 11E Street Cleaning:

County and communi t y hi ghway depart ment report s are combi ned i n

t he f ol l ow ng tabl e.

93



A

Page 12of 19

No. of No. of

Capaci t y,

Ref i l l s Days Used

i n Gal l ons

per day per year

I_

Vol ume per

Vehi cl e per Year

i n Gal l ons

Parks

20.0

Playgrounds 2.7

Cemeteries 2.0

70

ft/acre

140

7.0

ft/acre 19

6.0

ft/acre 12

Gol f Courses - The 62 acre muni ci pal gol f course was est i mated by

measur i ng t he r ate of f l ow and det ermni ng t he l engt h of wat er i ng

per i ods.

Typi cal water appl i cat i on:

10

hour s per day

250

days per year

804 gal l ons per m nut e

yi el ds

120,600,000

gal l ons per year or

370

acre- f eet

Hi ghway medi an st r i ps are watered by l arge tanker t r ucks,

operat ed si ml ar t o vehi cl e I rBf f i n the st r eet cl eani ng operat i on.

yi el ds 500 gal l ons x 10 r ef i l l s per day x 130 day/ year =650, 000 gal

=2

acre- f eet

Another 1/4 acre memor i al park i s watered but speci f i c quant i t i es

are not recorded. Water use i s est i mated at 1 acre- f oot and

i ncl uded as l l Other l fandscapi ng.



APPENDIX A

Page 13 of 19

Line 11K Water Quality Testing

Water amount s used f or test i ng are l ess than 500 gal l ons per year

( 0

acre- feet).

Line 11L Process Water

Treat ment pl ant operat ors do not mai ntai n speci f i c records.

oper at or s est i mat e 0.2 acre- f eet rel eased t o waste af t er f i l t er

backwash.

The

Line 14 Identified Water Losses

Line 14A Accounting Procedure Errors

Four meter readers were accompani ed on thei r r ounds f or one- hal f

day each. Thi s procedure sampl ed approxi matel y

800

connect i ons.

Thi s ef f or t pl us revi si on of t he bi l l i ng department ' s comput er

procedures r esul ted i n t he di scovery t hat 0.5 percent

of

r esi den-

t i al met er s were i noper abl e or msread.

Est i mat ed l oss:

0.005 x 10,200

connect i ons

x .7

acre- f eet / year

35.7

acre- f eet

Line 14B Illegal Connections

Dur i ng t he meter readi ng r ounds, one smal l shop was di scovered

usi ng water where t her e was no meter.

Est i mated l oss:

1

acre- f oot

Line 14C Malfunctioning System Controls

Usi ng an updated systemschemat i c al l systemcont r ol s were

methodi cal l y checked.

They al l operat ed correctl y.

Line 14D Reservoir Seepage

Each of t he syst ems cl osed r eservoi r s were i ndi vi dual l y val ved

of f f romt he system f or 24 hours.

eval uat i on.

One tank showed change i n

Est i mat ed annual l oss = 175 gal l ons

x

365 days

=

63,875 gal

= 0.2

acre- f eet

95



APPENDIX A

Page 14 of 19

Hole Size

Diameter

Line 14E Estimated

lass:

Total Loss i n

Date of

Number of Days TOTAL LOSS

Gallons per Day

Repair

Leak Existed i n Gallons

Crystal Lake

is

an open reservoir of

5

acres surface area.

Estimated evaporation i n excess of rainfall

i s

6 feet per year.

Estimated

loss = 6

fee t

x

5 acres

=

30 acre-feet

Line 14G Discovered Leaks

Work records repo rt four excavations fo r leak repa ir .

emergency repairs with lar ge leaks believed t o be short-lived

(30 days undetected) due t o th ei r disr upti ve nature.

two

were

assumed t o have been ac t ive the ent ire year

u n t i l their

discovery. Leak r a t e s

were

not estimated

i n

the f ie ld .

The

ra tes

were

estimated

from

the appropriate hole

s ize

i n

the pipe

using Greeley's formula a s shown i n Table 5 of t h i s guidebook.

A l l mains involved operated a t 50 psi.

Two were

The other

1 243,000

5/15/83 30

7

, 90, 00

1 243,000

6/18/83

30

7 ,

90

000

0.25" 15,200 6/25/83

180

2,736,000

0.25" 15,200 10/28/83 300 4,560,000

TOTAL LOSS

......

21,876,000

= 67 acre-feet

Line 14H Thefts

No t h e f t s were ident i f ied.

Line 18A Cost

of

Water Supply

Purchase price of water from

CC

Aqueduct

z

$225/acre-feet

Line 18B

Variable Operations

&

Maintenance Costs

Power Purchases = $45/acre-foot*

Water Treatment

=

$Vacre-foot*

K F K l m T e p o r t t o -the S G t e Controller



APPENDIX

A

Page 15 of 19

Sumnary of r ecommendat i ons for system i mpr ovement s resul t i ng f romwater audi t .

Conduct Leak Detect i on Program

Cust omer meters w l l be tested when recei ved f romt he manuf act urer

The revi sed account i ng bi l l i ng programs w l l check account s f or st opped

meters.

Recommendati ons ar e bei ng made that t he publ i cl y owned parks, pl aygr ounds,

cemeter i es, and gol f cour ses be metered.

The l eak repai r cr ew w l l be tol d to measure l eak di schar ge when l eaks ar e

uncovered.

Water audi t s are t o be per f ormed annual l y.

97



APPENDIX

A

Page 16 of 19

LEAK D ETECTION AND REPAIR PLAN

WORKSHEET

Agency Name:

Y Z coun-tfia-ter District

Date:

7 / 1 8 / 8 5

A. Area to be Surveyed

1.

2.

3.

4.

Usi ng t he r esul t s of t he water audi t , show on a map whi ch areas

i n t he di st r i but i on systemw l l be surveyed.

areas have t he hi gher potent i al f or r ecover abl e l eakage.

Descr i be each area under B-2. ( I t ems to consi der i ncl ude r ecor ds

of previ ous l eaks, t ype of pi pe, age of pi pe, soi l condi t i ons,

hi gh pressur es, ground sett l ement , and i mproper i nst al l at i on

procedures.

)

Tot al m l es of mai n t o be surveyed: 146

.

I f l ess than t he

t otal system i s bei ng sur veyed, t he cal cul at i ons f or t he

benef i t : cost rat i o must ref l ect t he reducti on.

t he m l es of mai n, i ncl ude t he tot al l engt h of pi pe and excl ude

ser vi ce l i nes. 1

Average number of m l es of mai n surveyed per day:

Expl ai n i f more than

3

m l es per day.

can survey about t wo m l es of mai n per day.

i ncl ude di st ances bet ween ser vi ces, t raf f i c and safet y

condi t i ons, and number of l i st eni ng cont act poi nts. )

I ndi cat e whi ch

(When cal cul ati ng

2.0

I t ems to consi der

( The average survey cr ew

7 3

umber of worki ng days needed t o compl et e survey: _

( Di vi de Li ne

2

by Li ne 3.)

B. Procedures and Equipment

1.

Descr i be t he equi pment and procedure you w l l use to det ect l eaks.

EXDer i enCe has shown that t he best r esul t s have been obt ai ned bv

l i keni ng f or l eaks at _--l l syst emcont act poi nt s ( such as wat er -

met ers, val ves, hydr ant s, and bl owof f s).

Purchase Heath Son-i-Kit. Attend Manufacturers Seminars and

DWR

Training. Conduct initial listening survey on all contact

points.

I ___

I

I

- - -__



APPENDIX A

Page

2

o f

4

Page 17 of

19

LEAK DETECTION AND REPAIR PLAN WORKSHEET

2.

3.

4.

5.

6.

Describe why

the

areas noted on

the

map A -1 ) have the greatest


Ar ea

1

-

Downt ownL ol d duct i l e i r z a i n s

_ _

Ar ea 2 - St eel mai ns over 40 years ol d

Ar ea 3 - Remai nder of syst em

-

_ I ___

If

you

w i l l

not

be

l i st e n in g f o r l ea ks a t a l l

sys t em

contact

point s, descr ibe your plan for ef fec tiv ely detectin g leaks.

Not appl i cabl e

-

cr ew w l l l i s t en for l eaks on al l cont act

- -

poi nt s.

Describe

the

equipment and procedure you w i l l use t o pinpoint

the

exact location of the

detected

leaks.

W l l use l ow f r eauencv er ound m cr oDhone to l i st en over

~ e n t ~ s , . _ ~ ~ s r L L ~

n

-dLffiraalr si t uat ons.

__

-_

Describe how

the

leak detection

team

and

the

leak repair crew

w i l l work together. How

w i l l

they resolve

the

problem of dry

holes?

The l eak det ect i on cr ew and t he repai r cr ew wi l l j oi nt l y

excavat e al l l eaks f or t he f i r st 3 weeks and r esol ve and dr y

hol es t her eaf t er .

--

--

Describe the methods you w i l l use t o determine

the

f low ra tes for


Bucket and st opwat ch met hod wi l l be used on smal l l eaks.

l arger l eaks the di amet er of t he hol e and t he pr essur e wi l l be

measured and used i n t he Gr eel ev f or mul a as shown i n t he Gui debook.

For

-

_. I _

99



APPENDIX A

Page 18

of

19


Page

3

of

4

C.

Staffing

1.

How many agency st af f w l l be used? 2

Staff Cost I ncl udi ng Wages and Benef i t s:

Person 1 $/ hour 1 7 . 1 9 $/ day 1 3 7 2 -

Person

2

$/ hour

1 2 . 5 0

$/ day

-1M9n__

TOTAL $/hour 2 9 . 6 9 $/ day 237.52.-

2. How many consul t ant st af f w l l be used?

1

Cost of Consul t ant Staf f :

Person 1 $/ hour 3 1 . 2 5

__

$/ day 2 5 0 -

Person 2 $/ hour 0 $/ day ___

TOTAL $/ hour

3 1 . 2 5

-

$/ day

2 5 0

D. Leak Detection Survey Costs

Leak Detect i on Surveys: $/ day # DAYS Cost

1. Agency Crew Costs 2 3 7 . 5 2 7 3

$

1 7 . 3 4 0

2.

Consul t ant Crew Costs 2 5 0 . 0 0 1 5 $ 3 . 7 5 0

2 . 4 0 7 3

$

1 7 5.

Vehi cl e Costs

-

____

4 Other

5. TOTAL Survey Cost s

$ 2 1 , 2 6 5

E. Leak Detection Budget

2. Leak Det ect i on TeamTrai ni ng

$

_I_

. Cost of Leak Detect i on Equi pment $ 2 , 5 5 0

4 0 0

3.

Leak Detecti on Sur vey Cost s

$

2 1 . 2 6 5

-

4.

TOTAL Leak Detect i on Costs

$

2 4 , 2 1 5



APPENDIX A

Page

19

of 19

LEAK DETE CTION AND REPAIR PLAN WORKSHEET

Page

4

of

4

E

Leak Survey and Repair Schedule

Indica te rea l i s t i c , prac t ica l da tes .

1 .

2 .

3. When w i l l

leak repairs begin? Augu?Ll& 1985

4. When

w i l l

leak repairs be completed? __ January

10,

1986

When

w i l l

the leak survey begin?

When

w i l l

the leak s u rv e y be completed? __ _ecember 15. 1985

August 1, 985

_I _

Prep ared by:

- C. M. Biggs -_7/ 8/85_

Name Date

Title

Manager

-- - - ___

101



APPENDIX B

TYPES OF METERS

Velocity Meters

Propeller

The measuring element

i s

a rotor or propeller facing upstream that

is

rotated

by the moving water striking

i t s

angular blades.

diameter i n rel ati on t o the internal diameter of th e pipe, especially in the

larger sizes.

the re fore , th i s

meter

is intended primarily for main- l ine service

where

flow

rates do not change abruptly.

'Ihrbine

The

meter

co ns is ts of a very l i g h t waterwheel operated by th e current and

carries on its ax is a worm for a ctuatin g gearing and a to ta li ze r.

flow

is

computed from the rotations during a given period.

A

more

recent

design, th e magnetic flowmeter, requires electrical connections and

is

not a

ccmpletely self-contained un it .

Ultrasonic

Acoustic flowmeters operate on the principle that the propagation velocity

of

acoustic signals i n l iqu ids is changed when a component of the liquid's

veloci ty pa ra ll el s the direct ion of acoustic propagation. In practi ce, up t o

four acoustic paths are

set

up a t an angle t o

the

flow. Each path

consists

of

two i de nt ica l t ransd ucers facing each other a t a p rec ise ly known distance.

Typical path angles vary from 30 t o 65 degrees, depending on available space

and accuracy requirements.

determined by measurement of the acou st ic t rave l

time

i n each direction.

li qu id v elo cit y measured a t each path is integrated across the flowing area to

determine th e t o t a l volume flow ra te . Such meter systems have very critical

in s t a l l at i on requirements and, while excel lent ly amenable t o computer input,

ar e ra ther cost ly .

require turbid r ather than clear flu id t o work effectivel y.

Electromagnetic

The electromagnetic flowmeter uses the same basic principle as the

ele ctr ica l genera tor .

When a conductor moves across a magnetic field, a

voltage is induced

i n the conductor, and the magnitude of t he vol tage

i s

d i r ec t ly proport ional t o the speed of t he moving conductor.

i s

a section of conductive liquid flowing i n a nonconductive pipe through a

magnetic f i e l d , and e lec tro des ar e mounted i n the pipe wall, the voltage

induced across th e electr odes should be proportional t o the flow ra te .

The propeller may be small i n

The propeller has a slight lag

i n

st ar t i ng or stopping;

The rate of

The average liquid's velocity on each path is

The

Both ul t rasonic and doppler flow measurement techniques

If the conductor



Differential Pressure

Flow TubedVenturi.

v e n t u r i t h roa t ,

i t s

veloci ty increases, resul t ing i n

a

pressure d i f f e ren t ia l

between the inlet and

throat

regions.

throat gradually increases in flow

area;

consequently, t h e f lu id ' s ve loc i ty

decreases, causing pressure recovery.

The

different ia l pressure across t h e

v e n t u r i ' s

throat can be recorded directly

or

t ransla ted into ac tual f low uni ts

by employing various types of di f f e ren t ia l pressure meters and capacity curves.

Venturi tubes are employed whenever the head

loss

is t o be minimized or

where f l u id s handled contain s uf fi ci en t amounts of materia ls

i n

suspension t o

render other devices such as or if i ce pl at es or flow nozzles

ineffec t ive ,

Widest ap plic atio n has tr ad it io na ll y been i n low-pressure gas

l ines

and large

water mains.

Measurements accurate to within plus

or

minus

0.5

percent can be made for

near ly a l l p ipe s izes.

arrangements may be critical.

V e n t u r i tubes

w i l l

maintain th ei r accuracy over re l at iv el y long periods.

I n

most

appl ica t ions the venturi is a self -cleaning device because i ts in te rna l

configuration allows smooth

flow

and minimizes erosion and clogging.

tubes

are mostly maintenance-free. They have no moving parts or mechanical

features or g lass tha t can

break or

become fatigued

or

st ra ined.

accuracy

of the

venturi

i s

d i f f ic ul t since al ter nat ive measuring devices

of

si mil ar accuracy and s i z e ar e oft en unavailable or d i f f i c u l t

t o

i n s t a l l .

ca l ibra t ing the venturi , it i s imperative t o check the venturi itself and not

j u s t the manometer apparatus.

with

the actual confirmed

flow.

with

a

hypothetical standard which

is

probably not occurring.

Orifice Plate.

is bored, u su all y con cen tr ica lly , a hole of predetermined siz e.

inserted across a st ra ight run of pipe.

Pressure

tap s ar e provided,

either

a t

specified distances upstream and downstream from the or i f ice plate or within

or if i ce flanges, by which th e orifice pla te is inser ted in

the l i n e .

The determination of the relation between

flow rates

and di ff er en ti al pressures

has

been reduced t o formulas by

which

an or if ic e coef fici ent can be readil y

computed for any size of

orifice

i n any size of pipe.

Pitotmeter.

pressure di ffer ence s associ ated with th e pi t ot tube when

it

is

inserted

i n t he

pipeline.

Then th e ve loci ty measurements a r e mul tip lied by the proportional

cross

sect ional area to determine the fluid

flow.

flows is t h e to ta l flow within t h e pipe.

A s

f l u i d

passes

through the reduced area of

t h e

That passage i me di at el y following th e

For larger diameter pipes piezometer rings and tap

Venturi

Testing the

When

Be su re t ha t

t h e

gauges a re cali br ate d

to

agree

Do not ad just the

manometer

apparatus

t o

agree

The

or i f ice sensing uni t cons is t s

of

a round plate i n

which

The

p l a t e

is

The

p i to t tub e measures f lu id v elo cit ies by

i ts

s e n s i t i v i t y t o

Velocity measurements a r e made along a tr an se ct in si de the pipe.

The

sum

of

a l l

th e proportional

Positive Displacement Meters

Disc Measuring Cham ber

The nutating disc

meter

consists of a movable disc mounted on a concentric

104



sphere.

and top and bot tom surf aces that extend coni cal l y i nward.

f romrotat i ng about i t s own axi s by a radi al par t i t i on that extends across the

ent i re hei ght of t he worki ng chamber.

part i t i on.

axi s.

traces

a

ci rcul ar path as i t i s dr i ven by the nutat i ng mot i on.

The di sc i s contai ned i n a worki ng chamber w t h spher i cal si de wal l s

I t i s restr i cted

The di sc i s sl ot ted t o f i t over thi s

The water ent ers t he si de of t he meter and st r i kes t he di sc,

A

pi n ext endi ng out f r an the i nner spher e, perpendi cul ar t o the di sc,

f orci ng i t t o r ock (nutate) i n a ci rcul ar path w t hout r ot at i ng about i t s own

t he undergear t hat cont r ol s the meter' s regi st er .

Thi s pi n dr i ves

Compound Meters

Thi s meter measures over a w de range of f l ow, i ncl udi ng very l ow f l ows.

i s cal l ed %ompound' ' because i t has a l arge t urbi ne meter on t he mai n l i ne

and a smal l meter on a bypass l i ne, w th a val ve to di rect water t o one or the

other meter aut omati cal l y. Someti mes both meters are i n t he same housi ng.

Compound meters may have ei ther si ngl e or doubl e regi st ers.

I t

Proportional or Fire Line Meters

The proport i onal meter measures

a

smal l but r el at i vel y const ant percent age of

t he wat er f l ow ng through the l i ne.

meter regi st er

so

that i t r ecor ds t he total quant i t y that has passed through

t he mai n l i ne. Thi s i s accompl i shed by provi di ng an expanded sect i on of t he

l i ne w th a r i ng at t he downst reamend havi ng an i nt ernal di ameter equal to the

nomnal pi pe di ameter . The rest r i ct i on r i ng creates a drop i n l i ne pressure

j ust bel ow i t ( compared w t h f ul l l i ne pressure upstream. Thi s di f f erent i al

i n pressure f orces a por t i on of t he water through the smal l di spl acement - t ype

bypass meter.

A mul t i pl yi ng f actor i s bui l t i nto the

Open Channel Meters

Weirs

A wei r i s an obst r uct i on bui l t across an open channel over whi ch t he water must

f l ow

Sharp- crest ed wei r s have t hree basi c conf i gurat i ons:

and Ci pol l et t i .

Flumes

The water usual l y f l ows t hrough an openi ng or notch on the wei r pl ate.

r ect angul ar , V- not ch,

Fl umes are speci al l y desi gned, open channel f l ow sect i ons w th a restr i ct i on

that i ncreases f l ui d vel oci ty.

ci rcul ar pi pe sect i on.

They can be desi gned f or i nst al l at i on i n

a

Fl umes have sever al advantages over wei rs. The f l ow vel oci t y through f l umes i s

hi gh; t heref ore,

they tend t o be sel f - cl eani ng syst ems that mni mze deposi t i on

of sedi ment or sol i ds.

exper i enced w t h wei r s,

a

deci ded advant age f or i r r i gat i on.

Fl umes can operate w th much smal l er head l osses t han

A Parshal l f l ume i s empl oyed where i t i s i mpor tant t o mai ntai n a l ow head

l oss

or where t he l i qui d cont ai ns a l arge amount of suspended sol i ds.



APPENDIX C

RECOMM ENDED USES OF METERS BY CLASSIFICATION

5 P e

Size

Applications

Positive

518"

Resi dences, smal l apart ment s, smal l busi nesses.

Displacement

Demand f l ow rates: 1/8 t o 29 gpm

Maxi mumcont i nuous demand to

10

gpm

3/41' Large r esi dences, smal l t o medi um apar tments.

Demand f l ow rates:

1/4

t o 30 gpm

Maxi mumcont i nuous demand to 15 gpm

1

I Medi um apar t ment s, beauty par l or s, barber shops, smal l

mot el s, f i l l i ng st at i ons, smal l busi nesses, i ndustr i al

processes.


3/8

to

50

gpm

Maxi mumcont i nuous demand t o

25 gpm.

1-1/2 Medi ummot el s, hot el s, l ar ge apar t ment s, smal l

i ndust r y, smal l processi ng pl ants.

Demand f l ow rates: 5/8 to

100

gpm

Maxi mum cont i nuous demand to 50 gpm

2 Larger hot el s, mot el s, apar tment compl exes, i ndust r i al

pl ant s, processi ng pl ants.


1-1/4

t o 160 gpm

Maxi mumcont i nuous demand to 80 gpm

Class II- 2 Medi um t o l ar ge hot el s, mot el s, l ar ge apar tment

Turbine

compl exes, i ndustr i al pl ant s, processi ng pl ant s,

i rr i gati on.


3

to

200

gpm

Maxi mum cont i nuous demand tO

160

gpm

3" Lar ge hot el s, mot el s, i ndustr i al pl ant s, processi ng

pl ant s, i rr i gati on.

Demand f l ow rates: 4.3 t o 450 gpm

Maxi mum cont i nuous demand to

350

gpm

107



TABLE C-1 (a n t. )

Lar ge i ndustr i al and processi ng pl ant s, i r r i gat i on,

r ef i ner i es, pet ro- chemcal s, pump di scharge.

Demand f l ow rates: 25 t o 2,500 gpm

Maxi mum cont i nuous demand

-

1,000

gpm

Lar ge i ndust r i al manuf actur i ng and processi ng pl ant s,

i r r i gat i on, pump di scharge.

Demand f l ow rates: 25 t o 2,500 gpm

Maxi mum cont i nuous demand -

2,000

gpm

4

6

Class

I-

8 I ndust r i al , manuf act ur i ng, pr ocessi ng, pump di scharge.

'lhrbine*


140

to

1,800

gpm

Maxi mum cont i nuous demand - 900 gpm

10

I ndust r i al , manuf actur i ng, processi ng, pump di scharge.


225

t o 2,900 gpm

Maxi mumcont i nuous demand to

1,450

gpm


400

to

4,300

gpm

Maxi mum cont i nuous demand to

2,150

gpm

12

I ndust r i al , manuf act ur i ng, pr ocessi ng, pump di scharge.

Com pound , New High-

Velocity Styles

Medi um mot el s, hotel s speci al cust omers havi ng hi gh and

l ow demand; school s, publ i c bui l di ngs, l arge apar tment

and condomni umcompl exes, hospi tal s.

2


1/4

t o

160

gpm


160

gpm

3 Demand f l ow rates:

1/2

t o

350

gpm

4

Demand flow rates:

3/4

t o

1,000

gpm


350

gpm

Maxi mumcont i nuous demand t o 1,000 gpm

Compound

6


1-1/2

to

1,000

gpm

Older Styles


500

gpm

8


1

t o

1,600

gpm


800

gpm

10


4

t o

2,300

gpm.


1,150

gpm

................................................................................

*

Cl ass

I

Tur bi nes bel ow

8

i nches ar e not i ncl uded because of t he hi gher per-

f ormance

of

Cl ass I1 mdel s.

108



TABLE C-2

AME RICAN WATER W ORKS ASSOCIATION TURBINE METER STA NDARDS

FOR CUSTOMER SERVICE

Meter

Size

(in)

Safe Maximum Maximum Rate

Operating for Continuous

Capacity Duty

( P F d

kpm)

Maximum

Loss

Normal

of Head at Safe

Maximum Operating Flow

Capacity Limits

(psi

1-1/2

2

3

4

6

8

10

12

2

3

4

6

8

10

12

Class 1-VerticalShaft

&

Low-Velocity Horizontal Type

100 50 15

160 80 15

350 175 15

600

1,250

1,800

2,900

4,300

160

350

630

1,400

2,400

3,800

5,000

300

625

900

1.450

2,150

15

15

15

15

15

Class II-In-Line (High Velocity Type)

100

240

420

920

1,600

2,500

3,300

12 - 80

16 - 120

24

-

250

40

-

400

80

-

1000

225 - 2500

140 - 1600

400

-

4000

4 - 160

8

-

350

15

-

630

30 - 1400

50 - 2400

75

- 3800

120 - 5000



APPENDIX D

METER SIZING PARAMETERS

When the type of

meter

has been selected, the meter should

be

properly sized

for operation.

This

means that

it

must measure the water ac cura te ly through

t h e

f u l l range of the customer's use.

maximum flow for short periods and a lower flow for long periods without

sustaining damage or above normal wear.

Meters mean revenue, and revenue can be lost because a

meter

does not register

accurately. Loss of re gis tr ati on can re su lt

from

wear, improper installation,

and improper s i z e or type of

meter.

Water meters ar e designed t o

d e l i v e r

a

I f a meter is operating outside i ts intended range,

i t

cannot regis ter a l l the

flow, even though i t may be accurate.

flow a t the change-over point,

the

loss

i n

revenue can

be

substant ia l .

A

24-hour or 7-day recorder a ttached t o a water meter w i l l provide maximum,

average, and minimum r a t e s of flow, which ar e ess en ti al i n determining whether

the

meter

is t h e proper s i z e and type fo r

the

ins tal lat ion. Without comparing

t h i s information

with

the meter's capacity,

the selection

of

a proper s i z e and

type of a water meter becomes a matter of guesswork based on experience.

large meter installations, a wrong guess based on experience that is not

representative of a particular situation can

be

costly and cause a considerable

loss of revenue.

Large water

meters

register flow inaccurately for several reasons.

a r e

these:

With a compound meter with appreoiable

For

Among them

The wrong size or type of water

meter

was

selected.

meter was selected to match the size of the service. From the standDoint

In some cases, the

of income, i t would be

better

to assume that the meter should

be

m a i l e r

than

the

service; however, t h i s

is

no time for assumptions. O f course,

flow should not be re s t r i c t ed ,

but with the amount of revenue a t s ta ke ,

meter sizing should

be

based on

the

type of factual

information provided by

a recorder chart .

A

change i n customers occurred a t a sp eci fi c lo cation.

profile of the new customer often differs considerably from that of the

The usage

original customer.

A change i n customer usage due t o water conservation or changes i n

production and/or products dealt with.

A

meter should

be

of adequate size

but

not oversized.

on

the

maximum

and

minimum demand and average usage rate of the customer.

Sizing should be based

The AWWA

has established standards on flow capacities and maximum pressure

losses for cold-water

meters.

lower pressure losses.

loss

flow curves provided by the manufacturer fo r newer models,

as appropriate.

N e w meters have a ls o been designed t h a t caused

The estimator can follow

the

AWA standards or the head-

1 1 1



Tables

D-1,* D-2,*

and

D-3

provide data from which approximate pressure loss

can

be

determined.

curves of several types

of

1975-model meters and averaged t o produce t ab le s of

values that the estimator can use when rat ing curves are not available .

These

tables are not applicable to some of the e a r l i e r meters, and the estimator

should use then only as approximations for

late-model

meters.

There

are several important considerations

i n

sizing a

meter

ins ta l l a t ion .

The flow requirement, not the pressure loss through the meter, should determine

the size of

the

meter

t o

be ins ta l led .

pressure l o s s can mean low flows w i l l f a i l t o r e g i st e r.

the

cost of maintenance.

Furthermore, i f

there

is good reason t o bel iev e t h e

customer plans t o incr ease t h e demand for water, the estimator should provide

for large r metering fa c i l i t ie s la te r, adding a meter box and connections that

w i l l meet future needs.

These t ab les are based on pressure-flow da ta taken from

Oversizing a meter t o lower the

It

w i l l also increase

Size

( i n )

TABLE D-1

DISPLACEMENT-TYPE METERS MEETING AWWA SPECIFICATIONS

FLOW-PRESSURE LOSS AVERAGES OR 1937-MODEL MET ERS

Maximum Reconmended Design

Capacity Criteria -80 percent

AWWA

Flow of Maximum

Criteria Capacity

(gpm) (psi) (gpm) (ps i )

Recmended for

Continuous Flow- Brands

30

Percent of

Maximum Capacity

Meters

(gpm) (ps i ) Avgs

.

5/8 x

314 20 10.4

16

6.1

6 0

1 .o

6

314

30

10.6

24

6.9

9.0 1.05 6

1

50

9.3

40 6.3 16.5

1 .o 6

1-1/2 100

11.3

ao

8.6 30.0 0.9 6

2 160 10.4 128 6.5 38.0 0.5

6

3

300

13.1

240

8.3

90 0

1 1

3

* American Water Works Assoc iat ion , Sizing Water Service L i n e s and Meters9

AWWA

Number

M22.

112



TABLE

D-2

COMPOUND-TYPE METERS MEETING AWWA SPECIFICATIONS

FLOW-PRESSURE

LOSS

AVERAGES

OF

1973-MODEL METERS

Si ze

(i n)

Maxi mum

Capaci t y

A W A Fl ow

Cri t eri a

(gpm (psi )

Recomended Desi gn

Cri ter i a- 80 Percent

of

Maxi mum

Capaci t y

(gpm

(psi )

2 160

9. 2

128

61

80 26 3

3 320

13.4

250

8.9 160

4.2 5

4 500

9.6

400 6.3 250

35 5

6

1000

9.4 800 5.8 500 2.5 4

8 1600 120

1280

7.8

800 4.O 3

Recomended for

Conti nuous Fl ow- Brands

Maxi mum Capaci t y Meters

(gpm)

(psi )

Avgs

.

30

Percent of

of

Si ze

(i n)

-

2

3

4

6

Recommended Desi gn

Cri ter i a- 80 Percent

of Maxi mum

Capaci ty

(gpm (psi )

TABLE

D-3

TURBINE-TYPE METERS MEETING AWWA SPECIFICATIONS

FLOW-PRESSURE LOSS AVERAGES OF 1973-MODEL METERS

Recommended for

Conti nuous

Fl ow-

Brands

50 Percent

of

of

Maxi mum

Capaci t y

Meters

(gpm (psi )

Avgs

.

Maxi mum

Capaci t y

A W A

Fl ow

Cri teri a

(gpm)

(psi )

160 4.5

350 4.6

600 3.5

1250 3.5

128

28 80 1 .o

280 30

175 12

480 2.1

300

0.8

1000

2.0 625

0.7

5

4

4

4

113



APPENDIX

E

METER INSTALLATION CONSIDERATIONS

Correct

meter

i n s t a l l a t i on is highly important. Because a meter

is

a

mechanical device, it begins t o wear and lose accuracy from the day it is

insta l led.

i n s t a l l a t i o n t o

f i e l d

test

meters

i n line for accuracy.

When ins t al l i n g la rg e meters,

i n c l u d e

the following:

1 .

Isolation valves

i n

both the

in le t

side

and

the

out le t

s ide

of

t h e

meter.

2.

In

time

it w i l l stop funct ioning. Provisions should be made during

Test plugs downstream of

the meter

between the meter and

the

downstream

iso lat ing valve.

A meter

bypass

with

isolating valve or a bypass

meter

t o provide water t o

the customer while the meter is being serviced.

should

be

placed upstream of t h e inlet isolating valve and downstream of

the out le t isola t ing valve so t h a t

it

forms a U around t he main meter.

I f

a

meter i s

ins ta l led

with

a bypass meter, the bypass

meter

should remain

open and a check valve mus t be in st al le d downstream t o for ce the water at

low

flow

through

the

bypass

meter.

If

t h e

meter

i s

not installed

i n

t h i s

manner,

the

low flows w i l l pass unregistered through the large meter

because water

follows

the

path of least resistance.

The

check valve should

be either in te rn al ly spring-loaded or external ly controlled so tha t a

differential pressure of about

5

t o 10 pounds

is

requi red t o open th e check

valve.

If

meters

are ins ta l led i n pa ra l l e l , one meter should ac t a s a primary

meter

and the other as a secondary

meter.

downstream of the secondary meter t o

ensure

a pressure loss of a t l eas t 5

t o

10

pounds through the primary meter before the secondary meter begins

operating.

register low flows.

To

ensure proper

meter

functioning (by reducing turbulence), i n s t al l the

meters according t o th e manufacturer's spe cif ica tio ns governing the number

method i s to insta l l s t ra ightening vanes.

3.

The bypass connection

To do t h i s , place a check valve

This

provision

is

necessary t o make ce rt ai n both

meters

4.

of straight pipe diameters upstream and downstream of

t he meter.

Another

When

ins ta l l ing turb ine meters, use a strainer on

the

i n l e t

side

of the

turbine. The s tr ai ne r has two functions: t o keep forei gn matter

from

damaging

the turbine, and t o ensure th at the water approaching the turbine is f a i r l y

equal

i n

velocity across the

diameter

of the pipe and is not spiraling.



APPENDIX F

METER TESTING IN GENERA L

A water

meter,

l i k e any other mechanical device, is su bj ec t t o wear and

deterioration, and, over a period of time,

it

loses i t s peak ef fi ci en cy . How

long water

meters

re t a in their overall accuracy depends on many factors, such

a s

t h e

qual i ty of the water being measured, r at es of flow, t o t a l qua nti ty,

chemical buildup, and abrasive materials carried by

t h e

water.

determine

whether a specific meter

is

operat ing eff ic ient ly is t o

test i t .

Meters are

tested

fo r sev eral reasons, including ( 1 ) determining

the

t o t a l

mount

of

meter error

w i t h i n the

distribution system;

(2)

ensuring that

the

co st of water s er vi ce is equitably d is tr ib uted among a l l customers; ( 3 ) deter-

mining the mount of revenue l o s t t o the water u t i l i t y ; and

(4 )

determining

whether a meter is capable of re gi st er in g low flows. Unfortunately, displ ace-

ment

meters, th e type most comonl y used, may se ri ou sly under reg ist er

for

long

periods without completely ceasing t o operate.

The

only way t o

Elements

of

a

Meter Test

The three basic elements needed t o test overall meter efficiency are:

1.

For the operating range of

the

meter, design ate the number of di f fer en t

f low ra t es t o be

tested.

A t each designated flow rate, determine the volume of water t o be passed

through

the meter

for each test .

2.

3.

Specify accuracy limits t ha t

meters

must meet a t d i f fe r ing ra t e s t o

be

acceptable for use.

Test Rates

Three

r a t e s of flow--minimum, in te rmedia te , and maximum--are necessary t o

properly

t es t

displacement, compound, and propeller meters. For compound and

fire-service meters,

the

changeover point must be establ ished to determine

overall operational efficiency and accuracy of registration.

important t o est ab li sh a t what point a meter begins t o reg is te r low flow.

Low flows below that point do not produce revenue.

The

meter

testing program should begin

with

the

low flow rates.

If

in the

course

of tes t ing,

the

meter

speed changes,

be

sure there was no use by

the

customer.

since

the

high flow could flush out sand

and

other materials.

would t o t a l l y negate l a t e r low flow tests.

The intermediate rate

of

flow should be a t or near the high point of

regis t ra t ion (about 10 percent of rated capacity) t o ensure th at the meter

w i l l

not over re gi st er a t any r at e of flow.

Tests for full-flow accuracy are not necessary a t the "safe

maximum

capacity"

r a t e

shown

i n

the

appropriate

AWWA

standard because

meters

are

seldom

operated

It is a l so

High flows must be avoided pri or t o low and medium flow testing

Such flushing



a t rated capacity.

but is usually about 10 percent of rated

meter

capacity.

the accuracy curve is fa i r ly f la t , and accuracy differs

l i t t l e

over a wide

range of flows.

capacity are practical .

of small

meters.

The maximum point of registration depends on meter design

A t rates above that,

Maximum-rate

test

flows of about three- fourths of rat ed

They are esp eci all y advantageous i n mult iple tes t ing

Accuracy Limits

Accuracy

limits

are establ ished to ensure that water meters record as

accurate ly a s pos sib le and as commercially fe asi bl e.

register variably by

2

t o

3

percent over the e n t i r e range of flows.

not occur when t h e flow

is

s o low that i t f a i l s t o re gi st er. ) For example, a

5/8-inch

meter

i n good condit ion

w i l l

reg is te r w i t h i n the following limits:

95 percent or higher with a 1/4-gpm flow; a t a maximum of 101.5 percent with a

2-gpm flow (usually

10

percent of rated

meter

capa city ); and then a t not

less

than 98.5 percent with a 20-gpm flow.

It

i s not normally considered economically fea si bl e t o rep air older meters t o

bring them up t o t he accuracy

levels

achievable by new meters a t the minimum

ra te .

tables for

new

and repaired meters on the minimum flow test. The

l i m i t s set

for repaired

meters

ar e considered t o represent t hose t h at requir e good

meter

shop procedures. Repaired

meters

should re gi st er a t l e as t 90 percent on t h i s

test .

standards.

Meters tend to

(This does

a t

For t h i s reason, separate accuracy

limits

are shown i n

t he

following

A higher percentage

i s

recomended for desirable shop quality

Meter Test Alternatives

Meters can be tested in-place ( f i e l d t e s t ing) or i n the

meter

shop (bench

tes t ing) .

Field Testing

As t h e cost of meter removal and replacement increas es, f i e l d te s t ing becomes a

more attractive method.

portable meter test uni t

i s

adequate for smaller meters.

equipment compares a previously calibrated meter with the meter being tested.

I n f ie ld tes t ing , both

meters

must be f u l l of water and under p os it iv e pressure

and the c on tr ol valve t o regu la te flow must always be on

t h e

discharge

s i d e

of

the

cal ibra ted

meter.

Large meters can be tested with a pitotmeter.

The

The portable test

Bench Testing

A

meter

shop typica ll y uses equipment th a t va ri es from a simple Rotameter (r at e-

of-flow ind icat or) t o a volumetric test bench that can test several meters a t

one

time.

Rising costs of meter removal and replacement a re a l so causing many

u t i l i t i e s t o phase ou t t he i r meter shops and either replace their meters

without test ing, or send

them

ou t t o

be

tested.

For a detailed description of meter t e s t i ng , r e fe r t o the American Water Works

Association (AWWA) pub lica tion ,Water Meters--Selection, Ins ta ll at io n,

Testing, and Maintenance,

AWWA

Number M6.



APPENDIX G

METER TESTING WITH A

PITOT

ROD

The purpose of the p i to t rod is t o measure the

flow of

l i qu id

i n

a closed

conduit under pressure.

conduit and the diameter of the condui t. From these measurements,

t h e

flow

can

be calculated.

accuracy cannot be obtained with an "averaging pitot rod" but only with

a

p i t o t

rod th a t ca lcula tes the ve loc i ty prof i le .

The pitot rod can be used on any closed conduit which has been re t r of i t te d with

a one-inch corporation cock.

operator i n about two hours with good conditions.

The pitot rod can be u s 4 t o test the accuracy of large water meters, measure

the

flow

of a pipe, perform loss

of

head

tests,

determine Hazen's flow

coefficients, perform zone measurements, conduct f i r e flow tests, determine

di rec t ion of

flow,

determine 24-hour flows, and i nd ic ate flow rev ers als .

For directions on using a pi to t rod , refer t o t h e manual Practical Hydraulics

and Water Flow Monitoring Work&*, developed by Carl F. Buettner Workshops.

* Revised July 1982, Polcon Inc ., St . Louis, Missouri

The p i t o t rod measures t h e ve lo ci ty of f l u i d i n t h e

The

p i to t rod can be accurate to within about 2 percent. This

The

test

can be performed

by

an experienced



APPENDIX

H

LONG-TERM METER SURVEILLANCE

(Well-Suited For Large Meters and Large Revenue Producing Customers)

After

a meter has been tested and calibr ated , sur veil lan ce or review of

consumption records should be ini t ia t ed t o ensure the meter

w i l l

operate as

long and as accurately as possible a t th e l ea st possible cost .

A useful technique is t o review bi ll in g records a t regular periods f or each

meter.

necessary.

quarterly or semi-annual review w i l l be suffic ient .

l ea s t a 12-month period t o guard ag ains t seasonal changes i n

the

customer's

water use pattern.

n o t

changing and t he consumption records a r e dec linin g, then

the

meter may be

losing accuracy and should be scheduled for inspection and testing.

Flow rates

w i l l

vary from customer t o customer, even

where

meters of

the

same

s ize

are i n use.

useful t o record each customer's ty pi cal maximum and minimum monthly usage.

This

information can

be

used t o an ti ci pa te demand.

Computerization helps immensely, otherwise sampling techniques may be

It is not necessary t o review records every bi ll in g period; a

Compare the records for a t

Contact t h e customer and i f the customer's ac tu al usage

i s

Rates of use a ls o vary

with

the

season of

the

year.

It

i s

1 2 1



APPENDIX

I

CALCULATING EVAPORATIVE WATER LO SS

Evaporat i ve water l osses f roml arge bodi es of water i ncl ude water l ost di rect l y

t o the at mosphere f romopen- ai r ,

st andi ng bodi es of water .

are par t i cul ar l y si gni f i cant dur i ng hot weather at l ar ge unmet ered pool s and

reservoi rs.

f ountai ns.

Ponds and reservoi r s i n Cal i f orni a annual l y l ose an aver age of

50

t o

80

i nches

of water by evaporat i on.

Dur i ng the sumer , dai l y evaporat i on l osses may be

0. 33 i nches per day f romeach acre of pond or reservoi r sur f ace (about 9,000

gal l ons per day per acre).

Exposur e to w nds and hi gh ai r t emperatures are

pr i nci pal cont r i but i ng f actors.

over the water sur f ace, and the ai r i ncreases i t s capaci t y to hol d moi st ure as

i t s t emper at ure r i ses.

Cal cul at i ons of evaporat i ve l osses are possi bl e, but they are al so compl ex,

and t hey r equi r e detai l ed l ocal envi ronment al data not other w se normal l y

avai l abl e. To est i mate evaporat i ve l osses, use t he evaporat i on pan dat a for

l ocat i ons i n Cal i f orni a shown here i n Tabl e

1-1,

an excerpt f romEvaporat i on

f romWater Sur f aces i n Cal i f or ni a, Bul l et i n 73- 79, Cal i f orni a Depar t ment

of

Water Resources.

l ocat i ons t hroughout Cal i f orni a.

Evaporat i ve l osses

I t

i s

of t en di f f i cul t t o est i mat e l osses f romsmal l pool s and

The w nd di sr upts t he saturated boundary l ayer

The bul l et i n provi des monthl y t ot al evaporat i on data at 478

123



TABLE

1-1

MEAN A NNUAL EVAPORATION AT PRINCIPAL CALIFORNIA LAKES

(inches)

Location

Berryessa

Cachuma

Castaic

Clair Engle

Clear

Eagle

Elsinor

Folsom

Henshaw

Hetch Hetchy

Isabel la

Matthews

Millerton

Nacimiento

Oroville

Perris

P i n e

Fla t

Pyramid

San Antonio

San L u i s

Shasta

Silverwood

Success

Tahoe

Inches

78

69

a i

57

60

48

75

67

71

46

a7

74

86

71

67

68

87

76

109

68

a7

a7

.

a2

38

The

evaporation data i n Table 1-1 and Bulletin

73-79

represent what

is

sometimes called gross evaporation, which

i s

the actua l depth of water lo s t t o

the

atmosphere.

shown t o be la rg er than those for lak es, the data referenced here does not take

this into account. No adjustments of these da ta are expected t o be made by

users of

t h i s

Guidebook.

Although evaporation rates for evaporation pans have been



APPENDIX

J

LEAK DETECTION EQUIPMENT

(A

Partial List dated December 1991)

Thi s l i st may not cont ai n al l manuf act ur er s

of

l eak det ect i on equi pment

or

accur at e pr i ces.

equi pment .

DWR

makes

no

r ecommendat i ons on t he capabi l i t y

of

any

The i nf or mat i on pr ovi ded may not be cur r ent and ot her equi pment

may be avai l abl e.

5 P e Company

Soni c Heat h

Soni c Fi sher

Soni c Met r ot ech

Soni c Fl ui d

Conser vat i on

Syst ems

Soni c

,

Gol dak

Soni c Subt r oni c

Fuj i Tecom

Fuj i Tecom

Fuj i Tecom

Acoust i c Pol l ar d

Cor r el at or FCS

Cor r el at or Rubl e

Model

Aqua- Scope

Son- i - ki t

XLT- 20

HL- 20 0 0

HL

90

200L

s 20

777-A

WL- 200

HG- 10

FD-7

Geophone

9090

1000

Price

$ 1 ,6 5 5

$3,900

$ 1 ,3 4 5

$ 3 ,1 7 5

$ 1 ,3 4 8

$ 8 0 2

$ 2 ,9 0 0

$ 985

$2 ,178

$2 ,275

$

765

$

275

$44,000

$25 ,000

20,000

Telephone/State

9 1 / 37 1-2 52 0

(

CA)

916/371-2520 ( CA)

209/826-3292 ( CA)

415 / 940-4 90 0 (CA)

800/531-5465

(TX)

512/794-0222 (TX)

818/240-2666

( CA)

510/ 68 6-37 4 7 (CAI

510 / 68 6-37 47

( CA)

510/686-3747

( CA)

5 16 /7 4 6 -0 8 42

(NY)

800/531-5465 (TX)

512/794-0222 (TX)

800/347-8253 (MN)

The Amer i can Wat er Works Associ at i on Buyer ' s Gui de may l i st addi t i onal

equi pment .

303/794-7711 (CO)

125



APPENDIX K

WATER AUDIT AND LEAK DETECTION FORMS

NOTE

The forms in Appendix

K

may be “snapped

out”

for your convenience and ease of calculation.

127



WATER AUDlT WORKSHEET

Page 1

of

4

For

Water District:

Line

1

2

2A

2B

2c

3

4

5

6

7

a

9

10

Item

Uncorrected Total

Water

Supply

t o the Distribution System

(Total of Master Meters)

Adjustments t o

T o t a l

Water

Source Meter Error (+ or

-1

Change

i n

Reservoir and Tank

Storage (+

or -1

Other Contributions

or Losses (+ or

-1

TOTAL Adjustments t o Total

Water Supply (+ or -1

(Add

L i n e s

2A, 2B, and 2C.)

ADJUSTED TOTAL Water Supplied

to

the Distribution System

(Add

L i n e

1 and L i n e

3.)


Water

Use

Adjustments

Due

t o

Meter

Reading Lag T i m e (+ or

-1

Subtotal: Metered

Deliveries

(Add L i n e s 5 and 6 . )

TOTAL

Sales

Meter

Error

and

System Service

Meter

Errors

(+ or -)

CORRECTED

TOTAL

Metered Water

Deliveries (Add L i n e s 7

&

8.)

CORRECTED

TOTAL Unmetered

Water (Substrac t l i n e 9

from

L i n e 4.)

Supply

Water Volume Units' _

Subtotal Cumulative _

_

Total

_I

-units

of water

measurement

must

be consistent throughout the worksheet.

Their selection (e.g.,

acre-feet,

millions of gallons, hundred cubic-feet) i s

l e f t to the user.

129



Page 2 of 4

Line

11

11A

11B

11c

1 1 D

11E

11F

11G

WATER AUDIT WOR KSHEET

Item Water Volume

Total

Subtotal Cumulative

Authorized Unmetered Water

Uses

Firefighting

&

Firef ighti ng Training

Main Flushing

Storm Drain Flushing

Sewer Cleaning

Street Cleaning

-

Schools

Landscaping I n Large Public Areas

Parks

Golf Courses

Cemeteries

Playgrounds

Highway Median St r ips

Other Landscaping

11H Decorative Water F ac i l i t i e s

1 1 1

Swimning Pools

l l J Construction Sit es

11K

Water Qual i ty and Other

Testing (pressure testing

pipe, water quality, etc.)

11L Process Water a t Treatment

Plants

11M Other Unmetered Uses

12 TOTAL Authorized Unmetered

Water (Add

L i n e s

1lA

through 11M.)

Units*

--

I

-



Line

13

14

14A

14B

14C

14D

14E

14F

14C

14H

15

16

17

18

18A

18B

19

Item

WATER

AUDIT

WORKSHEET

Water Volume

Total

Subtotal Cumulative

TOTAL

Water Losses

(Substract

L i n e

12 from

Line 10.1

I den t i f i ed

Water Losses

Accounting Procedure Errors -

Illegal Connections


System Controls


Leakage

_I

Evaporation

I_

Reservoir Overflow

I

Discovered Leaks

-

. I

heft

TOTAL Identified Water Losses

(Add L i n e s 14A through 14H.l

Potential Water System

Leakage (Subtract Line 15

from Line 13.)

Recoverable Leakage


Cost

Savings

Dollar= U n i t of Volume

I_

Cost of Water Supply

-

Variable 0 & Costs

$ -

TOTAL Costs Per Unit of

Recoverable Leakage

(Add

Line

18A

t o Line

18B.) $

Page

3 of 4

Units*

131



Page

4 of 4

WATER AUDIT WO RKSHEET

Line Item

20 One-Year B e n e f i t fran

Recoverable Leakage (Multiply

Line

17

by

L i n e

19.)

21 TOTAL BENEFITS from Recoverable

Leakage

TOTAL COSTS of Leak Detect ion Project

(Multiply L i n e

20

by

2.)

22

23 Benefi t t o Cost Ratio

(Divide

L i n e

21 by L i n e 22.)

Prepared by:

Dollars per year

$

$--

-

Date



LEAK DETECTION AND REPAIR PLAN

WORKSHEET

Page 1 of 4

Date:

Agency Name: _ _

A. Area to

be

Surveyed

1.

2 .

3.

4.

Using the res ul t s of the water audi t , show on a map

which

areas

i n the

distribution system w i l l be surveyed.

areas have the higher potential

f o r

recoverable leakage.

Describe each area under

8-2.

(Items t o consider include records

of previous leak s, type of pipe, age of pipe, s o i l conditions,

high pressures, ground settlement, and improper installation

procedures.

Total

miles

of

main

t o be surveyed:

total system i s being surveyed,

the

calcula t ions for the

benefit:cost r a t i o must r ef le ct the reduction.

the

miles of main, include t he total length of pipe and exclude

service l ines .

Average

number

of

miles

of main surveyed per day:

Explain i f more than 3

miles

per day a r e surveyed.

survey crew can survey about two miles of main per day.

consider include distances between services , t r af f ic and safe ty

conditions, and number of listening contact points.)

Indicate

which

.

If

less

than the

(When calculating

(The average

Items t o

Number of working days

needed

t o complete survey:

(Divide Line 2 by Line

3 . )

B. Procedures and Equipment

1.

Describe the equipment and procedure you w i l l use t o detect leaks.

Experience has shown that

the

best

re su lt s have

been

obtained by

lis ten ing for leaks a t a l l system contact poi nts (such as water

meters,

valves, hydrants, and blowoffs).

133




Page 2 of 4

2.

Describe why t he area s noted on t h e map A - 1 ) have the greatest


_____ _ _ __

_ _ _

3.

I f you

w i l l not

be l i s ten ing

for

leaks a t a l l system contact

point s, describe your plan f or ef fec tiv ely detecting leaks.

4. Describe the equipment and procedure you w i l l use

t o

pinpoint the

exact location of t h e detected leak s.

5.

Describe how the leak detection team and t he leak rep air

crew

w i l l

work together.

How w i l l

they resolve t he problem of dry

holes.

6.

Describe the methods you w i l l

use

t o

determine the

flow

rates for




Page 3 of 4

1.

2.

How many agency s t a f f

w i l l be

used?

Staff Costs Including Wages and B e n e f i t s :

Person

1

$/hour

$/day -

Person

2

$/hour

$/day

TOTAL

$/hour

-

/day

How many consu lta nt s t a f f

w i l l be

used?

Cost

of Consultant Staff:

Person 1 $/hour $/day

Person 2 $/hour $/day

TOTAL $/hour $/day


Leak Detection Surveys: $/day

1.

Agency

C r e w

Costs

2. Consultant Crew Costs

3. Vehicle Costs

4.

Other

5. TOTAL

Survey Costs

. Leak Detection Budget

1 .

2.

Leak Detection Team Training

3. Leak Detection Survey Costs

4.

TOTAL Leak Detection Costs

Cost

of Leak Detection Equipment

Days Cost

$

135




E

Leak Survey an d Repair Schedule

Indicate real i s t ic , pract ical dates .

1.

When

2. When

3. When

4. When

w i l l

w i l l

w i l l

w i l l

Page

4

of

4

leak repai rs

leak repairs

the leak su rvey begin?

the leak survey be completed?

~

_

_ I _

begin? -

be

- --

ompleted?

Prepared

by:

--

Name Date

136



LEAK DETECTION SURVEY DAILY

LOG

Agency

Da to

__-

M o n t h

Day Yeor

Leak Detection Team Members:

Manufacture and models o f Equipment used:

Area Surveyed Map Reference

_

Street and

Block

N o r :

~

Page

-3

Coordinates

LEAK LOCATION O R ADDRESS AGENCY OR LEAK

LEAK TO BE LEAK NOT A

NO.

O F

SUSPECTED LEAK CUSTOMER PINPOINTED RECHECKED REPA IRED LEAK

A O R C Y OR N

Y OR N Y OR N DATE

I

I

I

I

I

~~ _____~

Indicate Number of Meter s Hydr ants

V o l v a s

L ia t e n in g P oin t s U s e d

- - -

Tes t Rods Other

-

-

Mi l * .

o f

Main Surveyed

-

Survey Time

- o u r s

Number

4

Leaks Suspected

T o

be rechecked ___

Number

Number o f Leaks P inpo in ted

-

Pinpo in t ing T ime

-

ours

Rema rks :

137



Page

1

of

2

LEAK REPAIR REPORT

Date of Repair:

(Month)

I D w ) (Y*a,)

WO No.

Foremon

~

Leak Iden tific ation Map Reference

Refer to Leak Discavery Report

Discovery Date Leak

No

Loca tion: (inc lude stree t name and number)

_

Page and Caardinates

For Main and Service Lateral Leaks Only

Sketch

a

rmp af the s itu including:

1.

Street nmme; north arraw

2. Meter number (if applicable)

3.

Mains and hydrants in shutdown

area.

4.

A l l

valves, valve numbers and show

If

Main ar Service Leak,

Attach Three Photos:

1.

Straight dawn aver leak

or

damage

2. Close-up of leak and damage

which were closed during repair.

5. Locate leak ta nearest intersection ar house with address.

Show distances to property liner or street centerlines.

3.

An

ather photo which you feel

w i h help.

Leak Found

?

( Y e r h o ) TYPE

OF

LEAK

Meter Leak

- Main Line Leak _. Joint Leak

-

Meter Spud Leak - Service Lateral Leak -

Other

Leak -

Meter Yoke L eak

-

Curb Stap Leak __

Fire Hydrant Leak - Describe

Valve Leak -

DESCRIPTION OF REPAIR

Damaged part was:

-

epaired

-

eplaced

I f

replaced, what material wos

I f repaired, what repairs were made?

Repair time (From To)

__Leak Clamp

-

epacked valve

Crew Size (perrons)

-Welded

-

ecaulked ioin t

Equipment Used far Repair

-Other (describe).

- ackhoe

-

umptruck

Repair C o s t s : Size of Leak

Materials

$

Measured GPM

Labor $

Equipment

$

Other $

Total

L

Estimated GPM

Method used:



R REPORT

Page 2 of

2

Description of Damage for Mains and Services

Whot part wns damoged?

Pipe barrel

-

lange nuts, bolts, t ie rods - plit

-

oint

-

ther (describe

-

ole

Valve - ircumferential split

Type

of

Breo

k

-

-

Broken coupling

Service pulled

Cracked at corp. stop

-

In your opinion, what caused the damage?

-

-

-

asket

blown

-

rushed pipe

Estimated age of eak in months

How Determined - racked

Be l l

Diameter of Main

or

lateral in inches

-

ther (describe)

Depth to top of pipe in inches

Pipe Moterial:

System Pressure

How Determined

-

al . Iron

-

uctile

Iron - . C.P.

- lack Iron

-

teel -

.V.C.

- ast

Iron

- opper

-

olybuty

lene

Examine

broken

edge of ca rt or ductile iron pipe:

Min. thickness Deter iorotion

Origiona I of good grey is on:

thickness metol remaining - utside

Inches Inches

-

nside

I s

there evidence

of

previous

leak

or

repairs in

same

general orea?

- es

-

o

repair clamps present

Las t repair date (i f known)

Number

of

previous leak

Cause of Leak

No - o not know

In

your opinion, should pipe be replaced?

-

es

-

If yes, exp lain extent:

FOR EXCAVATIONS

INDICA TE GROUND

CONDITIONS

Type

of

Soil: Exis ting Bedding: Type of Cover:

Rocky - andy - ravelhand - oncrete

-Clay

-

ard Pan

-

ative Soil

-

sphalt

-

oam

- ea Grovel - oil

-

ther

-

ther

139



LEAK DETECTION AND REPAIR PRO JECT SUMMARY

Page 1of 2

Agency ~

Name

of

Report Preparer

__

-

Date

~


TOTAL

Number of Days Leak Surveys

were

Conducted:

First Survey Date:

Number of

Meters

Hydrants Valves Test Rods

Other

Listening Points Used:

Last Survey Date:

Number

of Suspected

Agency Leaks:

Pinpointed

Survey Time: Miles

of

Main Pinpointing

Time:

hours

hours Surveyed : _ _

Average survey rate = Miles of main surveyed x 8 = miles per day

T o t z s u r v e y and pinpointing hours

TOTAL

number of v is ib le le aks reported sin ce survey s ta r te d, from

other sources (not discovered during leak detection surveys).

Leak Repair Summary

Date First Leak

Repair Made: Repair Made:

Number of Repairs Needing

Date Last Leak

Number of Repairs Not

TOTAL Number of

Excavation: Needing Excavation: Repaired Leaks:

-

TOTAL

TOTAL

Water Losses from Water Losses from Nonex-

TOTAL

Water

Excavated Leaks:- pn

cavated Leaks:

_ _ _

gPm

Losses: __ gPm

Excavated Leak Nonexcavated Leak

TOTAL

Repair Costs =air

-

Costs Repair Costs

Materials $ Materials $

aterials $

Equipment

$

Labor $ Labor $

Equipment

$

quipment

8

Other $

ther $

Subtotal $ Subtotal

$

-

Labor

$--

Other

$

TOTAL

$

-



LEAK D ETECTION AND REPAIR PROJECT SUMM ARY

Page

2

of

2

Leak Detection Project Cost Effectiveness

1 .

Calculate the value of water recovered ( V w r ) from a l l repaired

leaks.

= (Total leakage recovered i n gpm)(Conversion Factor) (Water cos t , Wc)

= 1

gpm fo r

2

years 3.23 acre-feet

=

L i n e

19

of Water Audit Report water purchase pr ice

+

operating costs

per u n i t of water

=

( gpm) (3.23 acre-feet/gpm) ( $ / a c r e - f e e t )

vwr = $

Determine the total cost of the leak detection survey.

.........

eak Detection Equipment $ _

Leak Detection Training

$

-

.........


Costs

......

$

COST of Leak Detection Survey

(B:C) equals:

$

Divide V w r from Step 1 by the total costs calculated i n Step 2.

Value of Water Recovered

Total Cost Leak Detection Survey

B:C

mile.

4. Determine

average survey costs per mile of main surveyed ( C / M ) .

C/M Total Cost of Leak Detection Survex $

Total Number of Miles Surveyed

141



POTENTIAL REVENUES FROM RECALIBRATED LARGE METERS

Date:

gency Name:

One may estimate revenue gains l i k e l y

from

customers with la rge

meters

found t o .

be

operating in accura tely (slowly or f a s t , but not broken).

records for

the

customer for

the

en ti re audit period should be ava ila ble t o

best

estimate the benefits .

-- --

The metered use

To ca lc ul at e

the

corrected

metered

volume

(CMV)

use the following formula:

_

UMV

(0.01 RE )

MV =

UMV

(Uncorrected

Metered

Volume)

is the

volume of water registered on

t h e

meter (from the bil l ing records), RE (Registration Error) is

the

meter

accuracy in percent, and 0.01 is a conversion fa ct or t o change percentage

t o a decimal.

For Example:

(Registration accuracy

determined

by meter tests) .

U W =

10,000 cubic feet (from bi l l in g records).

RE is 75%

CMV = 13,333 cubic feet

U N CO RRE CT E D CH RGES

CORRECTED CHARGES FOR

INCREASED

METERED BILLED

METERED

CORRECTED

REVENUES

( 1 ) VOLUME 12 months

VOLUME

VOLUME $

METER I D

(UMV) $

(CMV)

12 months (Col 5)-(Col 3)

I



i

t



Department of W ater Resources Headquarters Office is at 141 6 Ninth Street, P. 0.Box

acramento, CA 94236-0001,916/653-5584; with District Offices at:

Northern District

2440 Main Street

P.

0.Box 607

Red Bluff, CA 96080

Extension 262

San Joaquin District

3374 E. Shields Avenue

Fresno, CA 93726

9161527-6530

2091445-5262

Central District

3251 S Street

Sacramento, CA 95816

9161323-4891

Southern District

770 Fairmont Avenue

Glendale, CA 91203-1035

P.

0.

BOX

29068 (91209-9068)

8 181543-4600

n Water

Works

Association, Califomia-Nevada Section, is

at

475 South Arrowhead

H, San Bemardino, CA 92408; 714/888-7468.



Stde

of

Califomia-Resources Agency

Department

of

Water Resources

P.

0 BOX

942836

Sacramento,

CA 94236-0001

awwa- water audit and leak detection guide (1992).pdf

Documents