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Drinking Water Inspectorate | 55, Whitehall | London | SW1A 2EY | Tel: 020 7270 3370

http://www.dwi.gov.uk

Drinking Water Inspectorate | Ergon House, Horseferry Road, | London | SW1P 2AL | Tel: 0300 068 6400

www.dwi.gov.uk

PB 13776

Drinking water 2011

Public water supplies in the N

orthern region of England

Drinking water2011Public water supplies in the Northern region of EnglandJuly 2012A report by the Chief Inspector of Drinking Water

Northe rn reg ion

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Drinking water 2011

Northern region of England

Dr ink ing wate r 2011

2

Publ ished by

Dr ink ing W ater Inspectorate

Area 4a

Ergon House

Horseferry Road

London

SW 1P 2AL

Tel: 0300 068 6400

Website: http: / /www.dwi.gov.uk

© Crown Copyr ight 2012

ISBN: 978-1-905852-63-5

Copyr ight in the typographical arrangement and des ign rests wi th the Crown.

This publ icat ion (exc luding the logo) may be reproduced f ree of charge in any

format or medium provided that i t is reproduced accurate ly and not used in a

misleading context . The mater ia l must be acknowledged as Crown copyr ight wi th

the t i t le and source of the publ icat ion spec if ied.

Northe rn reg ion

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Contents

Overview of drinking water qual ity in the region 4

Water supply arrangements 9

Drinking water qual ity test ing 11

Drinking water qual ity results 12

Microbiological quali ty 12

Chemical qual ity 22

Maintaining water qual ity in distr ibut ion 35

Maintaining water qual ity at the tap 40

Drinking water qual ity events 45

Technical audit act iv it y 49

Annex 1: Further sources of information 57

Annex 2: Glossary and descript ion of standards 58

Annex 3: Drinking water qual ity events in the region 71

Annex 4: Planned drinking water quality improvements 95

Annex 5: Compet it ion in the water industry 99

Annex 6: Water company indices 101

Annex 7: Information and research publ ished by the 107

Inspectorate in 2011

Annex 8: Distr ibut ion of private water supplies 109

Dr ink ing Water 2011 is the annual repor t o f the Dr ink ing Water Inspecto rate and

compr ises reports cover ing publ ic and pr ivate water suppl ies .

Publ ic suppl ies – Th is par t descr ibes dr ink ing water qual i ty in the Northern reg ion. The

Inspectorate a lso publ ishes a ser ies of companion reports fo r o ther reg ions of En gland

(Centra l and Easte rn, London and South East and Western reg ions) and a separate

report fo r Wales.

Pr ivate suppl ies – A summary of in format ion on pr ivate water suppl ies i s reported fo r

England and Wales.

Al l par ts are avai lab le on the Inspectorate ’s w ebsi te www.dwi .gov.uk


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Overview of drinking water quality in the region

Drinking Water 2011 is publ ished as a series of seven reports, f ive of

which cover publ ic water suppl ies and two descr ibe pr ivate water suppl ies.

Each report presents information about dr inking water quality for the

calendar year of 2011.

The improving national trend in the qual ity of public water suppl ies since

1990 is shown in Figure 1. Compliance with the standards in the EU

Drinking Water Direct ive now stands at 99.96% for publ ic suppl ies in

England, however, the results for private water suppl ies in England are

of concern with 7.2% of tests fail ing to meet the standards in 2011.

Figure 1: Percentage of tests from public and private supplies fail ing

the drinking water standards (England and Wales combined)

0

1

2

3

4

5

6

7

8

9

10

Perc

enta

ge o

f t

ests

faili

ng

England and Wales public supplies England and Wales private supplies (data not available before 2010)

Footnote : Pub l ic supp l i es : Percentage o f tes ts fa i l ing is ca lcu la ted fo r samples taken in zones .

Pr iva te supp l ies : Perc entage o f tes ts fa i l ing is ca lcu la ted fo r a l l samples .

At the end of 2010, the regulat ions cover ing both public and private water

suppl ies were changed to address def ic iencies in the transposit ion of the

Drinking Water Direct ive into nat ional law . The infract ion case by the

European Commission was closed subsequently in September 2011. The

purpose of the 2010 amendments to the regulat ions was twofold: to make

enforcement mandatory for failures of standards in public buildings and

to make clearer the duty to minimise disinfect ion by -products.

In 2011, across 29 companies, over 43,000 tests were carr ied out at publ ic

bui ldings out of which 35 failed to comply with one or more of the

standards or indicator parameter values (Col iform bacteria, E.col i , iron,

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lead, nitr ite, taste, odour and turbidity ). In the Northern region failures that

arose due to arrangements in public buildings are described in the

Maintaining water qual ity at the tap sect ion .

In relat ion to how well companies are complying with the requirement to

keep disinfect ion by-products as low as possible, in 2011 , across England

and Wales, the annual average f igure for total tr ihalomethanes was 9.9µg/l

in groundwater suppl ies and 27.9µg/l in surface water suppl ies compared

to the standard of 100µg/l. For more information about tr ihalomethanes in

the Northern region see the Chemical qual ity – Disinfect ion by-products

sect ion .

This report describes the key facts about the quality of public water

suppl ies in the Northern region, which is served by six water companies.

Together the companies deliver water suppl ies to over 14 mil l ion

consumers.


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In addit ion, local authorit ies have identif ied 13,367 pr ivate water supplies

in the Northern region and the quality of these pr ivate suppl ies can be

found in the separate report Drinking Water 2011 – Pr ivate water suppl ies

in England. Annex 8 of this report shows the location of private suppl ies

reported to the EU under the Dr inking Water Direct ive. I t also shows small

shared suppl ies used only for domest ic purposes.

The results of test ing of public suppl ies in 2011 demonstrated that the

overall qual ity of drinking wat er in the Northern region was good, however,

the f igure for compliance with dr inking water standards at consumers’ taps

was 99.95%, down from the f igure of 99.96% reported in 2010 and below

the industry average. This f igure is made up of the results of al l the tests

Northe rn reg ion

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for 39 parameters with European or national standards . Across the region

al l tests for 27 out of 39 parameters gave satisfactory results. Fai lures

were recorded for E.col i, odour, taste, aluminium, iron, manganese, lead,

turbidity, nickel, benzo(a)pyrene, and four pestic ides (chlortoluron,

glyphosate, MCPA and metaldehyde).

Table 2 puts the failures into context with respect to the other regions of

England and Wales.

Table 2: Parameters exhibiting one or more failure of a standard

Parameters Wales

England

Central

and

Eastern

region

London

and South

East

region

Northern

region

Western

region

Microbiological parameters

E.col i

Enterococc i

Physical/chemical parameters

Odour

Taste

Aluminium

I ron

Manganese

Lead

Turbid i ty

Nickel

Benzo(a)pyrene

Copper

Ni tr i te

Bromate

Chlorto luron1

Clopyral id1

Glyphosate1

MCPA1

MCPP1

Metaldehyde1

Propyzamide1

1These parameters are pest ic ides .


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When the Northern region is judged by the Inspectorate’s four indices of

water qual ity performance, which look in turn at water treatment (covered

by two indices, process control and disinfec t ion), service reservoir integrity

and network maintenance, the changes in 2011 were improvement in the

f igures for service reservoir integrity (99.95%) and network maintenance

(99.85%). Figures for process control (99.98%) and disinfect ion were

unchanged. In this region all indices were at or above the industry f igure

except for network maintenance. Individual water company f igures are

reported in Annex 6 .

Across the region, in 2011, there were fewer events affect ing water qual ity

overall (70 compared to 92 in 2010). More than half of these events were

of a type that necessitated a detailed investigation by an inspector and

this compares unfavourably with the industry overall. Information about

al l signif icant events in 2011 can be found in Annex 3. In 2011, there were

no major or serious events. The number of each event type can be found

in the Drinking water qual ity events sect ion together with learning points

f rom other event assessments by the Inspectorate. In 2011, it was

necessary for the Inspectora te to take enforcement act ion in relat ion to

four events in 2011 (Hunt ington works, UUT: Northern Trunk Main, NNE:

Horsley works, NNE: Llwyn Onn, DVW ). In relat ion to one event (NNE) the

Inspectorate has init iated proceedings for the offence of supplying w ater

unf it for human consumption.

Turning to the planned improvements in drinking water qual ity in the

region, in 2011, the Inspectorate conf irmed the need for addit ional control

measures at one service reservoir (DVW). These addit ional requirements

are included in Annex 4 which sets out al l the improvement work that

companies are committed to complete in during the AMP5 period

(2010–2015).

In 2011, the Inspectorate provided industry advice and guidance on nine

topics to enable companies to comply with dr inking water regulat ions and

also publ ished nine research projects to support the industry in carrying

out regulatory r isk assessments (see Annex 7).

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Water supply arrangements

Six water companies supply drinking water in the Northern region: Dee

Val ley Water (DVW), Hart lepool Water (HPL), Northumbrian Water (NNE),

United Ut i l i t ies (UUT) and Yorkshire Water (YKS). This includes one inset

appointment; Peel Water Networks (PWN) suppl ies the Media City

development site in Salford Quays, Greater Manchester.

Figure 3: Map il lustrating sources of drinking water by zone across

the region

Much of the water suppl ied in the region is surface water ( 81%),

abstracted f rom rivers such as the Dee, Derwent, Eden, Lune, Ouse, Tees,


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Tyne and Wyre. The main reservoir sources supplying the region are the

Derwent reservoir in the Pennines and other large reservoirs l ike Kielder

in Northumberland, Haweswater and Thir lmere in Cumbria and Vyrnwy

in Wales. Natural lakes are an important regional water resource, with

abstract ions f rom Crummock Water, Ennerdale, W indermere and Ullswater.

Groundwater provides a valuable resource in the region (11%). Most

boreholes draw water f rom the sandstone aquifers, between Doncaster

and Selby, in the Eden Val ley, f rom Cheshire and West Lancash ire

aquifers and from the Fylde aquifer. Hart lepool Water relies exclusively

on groundwater f rom the l imestone aquifer in southeast Durham and this

source of water also suppl ies the Sunderland area (suppl ied by

Northumbrian Water). There is another import ant chalk aquifer in the

Yorkshire Wolds. The remainder (8%) of water suppl ies in the region can

be drawn from either surface or groundwater sources.

Private water suppl ies in the region are widely distr ibuted across the area.

These private suppl ies are more rel iant on groundwater (54%) than the

public suppl ies in the area (11%).

Summary facts about the drinking water supply infrastructure of the region

are given in Table 4 with outl ine geographical and demographic

information.

Table 4: Key facts about public and private water supply arrangements

in the Northern region

Public supplies Private supplies

Population supplied Water supplied (l/day) Abstraction points Treatment works Service reservoirs Water supply zones Length of mains pipe (km)

14,496,175 3,789 million 321

212 970 390 91,592.25

Population supplied Water supplied (l/day) Approximate number of private water supplies Total number of local authorities

234,602 95 million

13,367

72

Water composition

Surface sources Groundwater sources Mixed sources

81% 11% 8%

Water composition

Surface influenced supplies Groundwater sources Rainwater

46% 54%

<0.1%

Area of public supply

Cheshire, Cleveland, County Durham, Cumbria, Derbyshire (part), Lancashire, Merseyside, Greater Manchester, North Lincolnshire, Northumberland, Tyne and Wear and Yorkshire

Number of local authorities with private supplies

64

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Drinking water quality testing

Throughout 2011, water companies sampled drinking water across the

region to test for compliance with the dr inking water regulat ions. Almost

half (45%) of the tests were carr ied out on drinking water drawn from

consumers’ taps selected at random. For monitor ing purposes, company

water supply areas are divided into zones . Sampling in zones at

consumers’ taps is r isk based with the number of tests being higher in

zones with a large populat ion (maximum 100,000). Other sample locations

are water treatment works and treated water (service) reservoirs.

Collect ively, the six water companies carr ied out a total of 1,012,554 tests

during 2011. Only 374 of these tests failed to meet the standards set down

in the regulat ions or exceeded screening values .

Table 5: Number of tests carried out by companies in the region

Company

Place of sampling Number

of tests

per

company

Estimate

of

populat ion

Water

treatment

works

Service

reservoirs

Consumers’

taps

(zones)

Dee Val ley Water

5,856 (2)

472 (2)

4,397 (5)

10,725 110,000

Har t lepool Water

1,884 (3)

1,490 (6)

1,981 (3)

5,355 88,000

Nor thumbr ian Water

43,324 (33)

66,210 (218)

76,324 (75)

185,858 2,501,000

Peel Water Networks

0 (0)

0 (0)

458 (1)

458 175

Uni ted Ut i l i t ies

116,390 (82)

114,150 (371)

211,079 (230)

441,619 6,872,000

Yorkshire Water

103,891 (80)

107,371 (361)

157,277 (76)

368,539 4,925,000

Region

overall 271,345

(200) 289,693

(958) 451,516

(390) 1,012,554 14,496,175

Note: Numbers in b rackets re f lec t the number o f works , reservo i rs or zones operated by that

company in the reg ion in 2011. Some companies a re perm i t ted to ca r ry out some tes ts on

samples taken f rom supply po in ts ra the r than f rom consumers ’ taps .

The regulat ions require companies to test for specif ied parameters

at prescribed f requencies. Most of the test ing is f or parameters with

European or national standards, however, water companies are also

required by the regulat ions to test for other parameters , such as

ammonium, sulphate and colony counts. Across the region there was a

shortfall in samples because Hart lepool Water identif ied def iciencies in

sampling. The company reported the f indings to the Inspectorate as an

event and this is summarised in the Drinking water quality events sect ion .


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A summary of the results of test ing by companies for each parameter can

be found on the Inspectorate’s website (www.dwi.gov.uk) and on the CD

accompanying this report. Addit ional ly, the Inspectorate publ ishes the

performance indices for each company in Annex 6 annual ly.

Drinking water quality results

The key water quality results for the Northern region are presented in two

tables, one showing the results for microbiological parameters (Table 6),

the other deal ing with chemical and physical parameters (Table 8). The

microbiological quali ty of water is discussed f irst. Companies report al l the

results of the tests on a monthly basis to the Inspectorate. Also, tables in

Annex 6 describe the drinking water qual ity performance indices of each

company supplying in the region.

Microbiological quality

To protect public health, microbiological standards have to be met at each

individual treatment works and service reservoir. The signif icance of the

individual test results for each microbiological parameter at each locat ion

var ies and a single posit ive result cannot be interpreted without other

information. Al l companies are expected to follow best pract ice as set

out in The Microbiology of Dr inking Water publ ished by the Standing

Committee of Analysts (SCA) which can be found by vis it ing the

Environment Agency’s website (www.environment-agency.gov.uk).

Northe rn reg ion

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Table 6: Microbiological tests

The number of tests performed and the number of tests not meeting

the standard

Parameter Current

standard

Total number of tests

Number of tests not meeting

the standard

Addit ional information

Water leaving water t reatment works

E.col i 0/100ml 38,102 2 DVW (1), YKS (1)

Col i form bacter ia 0/100ml 38,363 19 DVW (1), NNE (4) , UUT (6), YKS (8)

Clostr id ium per fr ingens

0/100ml 14,574 15 NNE (6) , UUT (4), YKS (5)

Turbid i ty1 1NTU 38,137 16

DVW (1), HPL (1) , NNE (4) , UUT (6), YKS (4)

Water leaving service reservoirs

E.col i 0/100ml 48,326 3 UUT (1), NNE (1), YKS (1)

Col i form bacter ia

0/100ml in 95% of tes ts

at each reservoir

48,326 45

NNE (11), UUT (14), YKS (20) Al l 958 reservoirs in the region met the 95% compl iance ru le

Water sampled at consumers’ taps

E.col i 0/100ml 36,966 4 NNE (1) , UUT (2), YKS (1)

Enterococc i 0/100ml 2,987 0 1Turb id i ty is a cr i t ica l contro l parameter for wate r t reatment and d is in fect ion.

E.coli at works and service reservoirs

In 2011, out of a total of 38,102 tests at works, E.col i was detected in only

two samples (1 DVW, 1 YKS) and at service reservoirs, out of a total of

48,326 tests, E.coli was detected on three occasions, (1 NNE, 1 YKS,

1 UUT). This is s imilar to the situat ion across the Northern region in 2010

when there were four detect ions of E.col i at service reservoirs and none

at treatment works.

On detect ing E.col i, companies are required to act promptly to protect

public health. Their immediate response when f inding E.col i at a works

or service reservoir is to sample again, and more widely, to conf irm that

water being received by consumers is safe. In 2011, all these E.col i

detect ions were notif ied to the Inspectorate as events (see Annex 3).

In February, Northumbrian Water detected E.col i in a sample taken from

West Kyloe service reservoir (near Holy Island, Northumberland) . The

company removed the reservoir f rom service and carr ied out a n internal


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inspect ion of the asset. Points of minor ingress were ident if ied and

repaired before the reservoir was returned to service.

E.col i was reported in a sample col lec ted f rom Summerbridge reservoir

(near Dar ley, North Harrogate) in September. This reservoir is supplied by

Harlow Hil l reservoir via Eagle Hal l reservoir. Yorkshire Water took the site

out of service. An internal inspect ion and f lood test identif ied points of

ingress (a cable entry point and the roof seals). Repairs were made before

returning the reservoir to supply in December. The invest igation informed

the company’s understanding of the water supply system in this area and

this knowledge guided the inves t igation of another E.col i failure that

occurred in October at Harlow Hil l works, near Harrogate, North Yorkshire.

Clostr idium perfr ingens was also detected in a sample f rom this works in

November. The comprehensive invest igation of the whole supply , including

enhanced ( large volume) sampling , ident if ied ingress in two downstream

reservoirs (Eagle Hall and Harlow Hil l) and issues with an air valve on

a treated water main between Eccup works and Harlow Hil l reservoir.

Remedial works on cel l B and cell A of Harlow Hil l reservoir were

completed in December 2011 and February 2012 respect ively. The

Inspectorate has put in place a Not ice requir ing Yorkshire Water to

carry out enhanced monitor ing at Har low Hil l to verify water qual ity

is sat isfactory fol lowing a failure.

United Ut i l i t ies detected E.coli at Westhoughton reservoir (near

Westhoughton, Greater Manchester) in October and took the reservoir out

of supply for inspection. In December, during the f lood test to ver ify the

integrity of the reservoir roof , water was observed to be f reely f lowing into

the reservoir act ing as point of ingress for environmental contaminat ion.

The Inspectorate recommended complet ion of repairs before returning the

reservoir to service. United Ut i l i t ies conf irmed that the reservo ir remains

out of supply.

In June, E.col i was reported in a sample col lected by Dee Val ley Water

f rom Boughton works in Chester serving consumers in North East Wales

as wel l as Engl ish consumers in the Northern region. The company not if ied

the Inspectorate of an event (see Annex 3 and the Drinking water quality

events sect ion) and carr ied out an immediate investigat ion involving

samples f rom the key process stages at the works, including on -site

treated water storage and from the distr ibut ion system. This sampling

survey conf irmed that water in Boughton water tower was contaminated

with E.coli and the company removed it f rom supply. The Inspectorate was

very cr it ical of the fact that the company had ident if ied integri ty problems

with the tower in January and had been chlor ine dosing the tower over a

number of years fol lowing a previous detect ion of E.col i in August 2005.

A subsequent audit by the Inspectorate , in 2006, had expressed doubts

about the f itness for purpose of the tower. The Inspectorate has repeatedly

advised companies that manual dosing of sodium hypochlorite

Northe rn reg ion

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(dis infectant) is a short -term measure that should never be used as

a subst itute for remediat ion of structural or other integrity faults with

service reservoirs and towers.

The company has since ident if ied the fol lowing principal water quality

hazards in its r isk assessment for Boughton Tower; a complete loss of the

reservoir due to structural fai lure, failure of the roof ’s integrity and

contamination of water with animal excrement and gna w damage to the

infrastructure. The company has specif ied a number of control measures

to mit igate these r isks, including: regular inspections of the tower and its

roof ; continuous manning of the works ; chlor ine and f low monitoring ; the

abi l i ty to bypass the reservoirs; engineer ing controls ; a maintenance

schedule; and a competent operator scheme. The Inspectorate was very

disappointed about the length of t ime the company has taken to put in

place permanent solut ions to mit igate against these known risks.

Consequent ly the tower was taken out of service and enforcement act ion

was taken. A Notice has been in place since March 2012 to ensure that the

company carr ies out appropr iate remediat ion within agreed t imescales to

protect publ ic health.

In September, as a part of the Inspectorate’s r isk -based programme of

technical audit , the works and tower were vis ited and a number of further

def iciencies were highlighted (see the Technical audit act iv ity sect ion).

The company was required to further revise its r isk as sessment for the

site. The water tower wi l l not be returned to service unti l Dee Val ley Water

has completed al l remedial act ions.

Table 7: Detection of E.coli and Enterococci at treatment works,

service reservoirs and consumers’ taps

Company

E.coli in water leaving

treatment works

E.coli in water

leaving service

reservoirs

E.coli at consumers’

taps

Enterococci at

consumers’ taps

Dee Val ley Water

1 – 782 0 – 78 0 – 288 0 – 36

Har t lepool Water

0 – 220 0 – 298 0 – 228 0 – 20


0 – 6 ,143 1 – 11,035 1 – 6 ,500 0 – 545

Peel Water Networks

0 – 0 0 – 0 0 – 33 0 – 6

Uni ted Ut i l i t ies Water

0 – 16,522 1 – 19,020 2* – 18,133 0 – 1 ,804

Yorkshire Water

1 – 14,435 1 – 17,895 1 – 11,784 0 – 576

Region overal l 2 – 38,102 3 – 48,326 4 – 36,966 0 – 2 ,987

Note: Resu l ts are shown as the number o f pos i t i ve tes ts – the to ta l number o f tes ts .


16

Coliform bacteria at works

Testing for coliform bacteria gives reassurance that water entering the

supply was treated adequately to remove bacterial and viral pathogen s.

Repeated occurrences of coliform bacteria in samples f rom the same

works in one year are thus of concern and require act ion to be taken .

In 2011, this situation occurred at two sites: Sutton Hall (UUT) and Har low

Hil l (YKS). Disappoint ingly, the Northern region saw a substantial increase

in col iform failures at works, up to 19 compared to nine in 2010, returning

the picture to that reported in 2009 when there were 17 col iform failures

at works.

In September and November , Northumbrian Water detected col iforms

in samples f rom four works; Lart ington (near Barnard Castle

Northumberland) , Byrness (Northumberland) , Rochester (Northumberland)

and Warkworth (Northumberland) . In each case follow-up samples gave

satisfactory results and the company drained, insp ected and cleaned the

treated water reservoirs and contact tanks. No integrity defects were

observed, but at Warkworth works when investigat ing turbidity failures

Northumbrian Water found that contractors were using a hydrant without

a check valve adjacent to the sample point and prohibited its use in the

future (see the Turbidity at works sect ion).

Two col iform failures were reported in samples f rom Sutton Hal l No.2

works in the Wirral area of Cheshire operated by United Ut il i t ies. This

works treats water f rom the River Dee. Treatment includes coagulat ion,

clar if icat ion, rapid gravity f i l t rat ion, manganese removal and disinfect ion.

Fol lowing the f irst failure in May, United Uti l i t ies carr ied out a site audit ,

the f indings of which prompted the company to move the location of the

coagulat ion pH monitoring point to improve vis ibi l i ty and control. Fol lowing

the col iform failure in September, the company sat isf ied itself that the

works was performing within normal targets and ver if ied the accuracy of

the analysis. The company has since instal led new sulphur dioxide and

chlorine dosing equipment and inspected and cleaned both compartments

of contact tank B, and scheduled the same for contact tank A in 2012. In

addit ion to these col i form failures two events occurred at this site in 2011

(see Annex 3).

During 2011, United Uti l i t ies took act ion in response to col iform failures at

four works: Ridgegate; Franklaw; Oswestry; and Worsthorne New. A leak

on a sample l ine was repaired at Franklaw works and the sample l ine was

examined at Ridgegate works. At Oswestry, the company revised the site

r isk assessment to identify the need for remedial work on the contact tank

by December 2012. Rapid gravity f i l ter performance was evaluated at

Worsthorne New. Also, following coliform failures, Yorkshire Water found

integrity defects when inspect ing treated water tanks at four dif ferent

works: Lof tsome Bridge; Ingbirchworth No.2; Rivel in No.2; and Oldf ield.

Northe rn reg ion

17

Repairs were made in each case and further tests have given satisfactory

results. Companies are reminded that a reactive failure -based approach

to maintenance is not in l ine with the water safety plan approach and the

Inspectorate expects them to fully implement a proact ive , preventat ive,

r isk-based approach.

The Inspectorate has noted that Yorkshire Water found no cause for a

col iform failure at two works: Ir ton and Cowick works. There was a similar

previous, unexplained col iform failure at Cowick works in 2010.

The Inspectorate has noted that col iform bacteria were found in 19

samples f rom treatment works in the Northern region during the year

and this information wi l l be taken into account in the planning of the

Inspectorate’s forward r isk-based programme of technical audit .

Clostridium perfringens

This organism is a spore-forming bacterium that is exceptional ly resistant

to unfavourable condit ions in the water environment, such as extremes of

temperature and pH, and disinfect ion processes such as chlor inat ion and

ultraviolet l ight. I t is a normal component of the intest inal f lora of up to

35% of humans and other warm-blooded animals. These characterist ics

make it a useful indicator of either intermittent or historical faecal

contamination of a groundwater source or the performance of a surface

water f i l t rat ion plant. The detec t ion of any Clostr idium perfr ingens should

tr igger an invest igation by the water company.

In 2011, out of 14,574 samples taken in the region, 15 did not meet the

specif ied value (6 NNE, 4 UUT and 5 YKS).

On f ive occasions in 2011 Yorkshire Water detected Clostr idium

perfr ingens in samples f rom the following works: Elvington works near

York (January); Har low Hil l (November); and, in December, at Chellow

Heights near Bradford; Holmebridge near Holmf irth; and Longwood near

Huddersf ield. The company reviewed the performance of water treatment

in each case. At Holmebridge works , two f i l ters were found to contain

insuff icient media and the company enhanced monitor ing unti l the media

in the f i l ters was replaced. Backwashing was opt imised to prevent further

media losses. Companies are expected to monitor the depth of media in

f i l ters regular ly to ensure performance is not compromised. T his was a

recommendat ion of Cryptosporidium in Water Suppl ies – Third report of

the group of experts , November 1998 (Bouchier report –

http:/ /dwi.defra.gov.uk/research/bouchier/ ). At Elvington, Chel low Heights

and Longwood works nothing untoward was observed during Yorkshire

Water’s investigations. The detect ion of Clostr idium perfr ingens at Harlow

Hil l is descr ibed elsewhere (see the E.col i at works sect ion).


18

Both United Ut il i t ies and Northumbrian Water also test for Clostr idium

perfr ingens at consumers’ taps , despite guidance by the Inspectorate in

2009 that monitor ing for this indicator parameter should be appropriate to

its purpose, with test ing at consumers’ taps being l imited and only for the

purpose of making up the balance of the sample f requency set in the EU

Drinking Water Direct ive. The pract ice of these companies is becoming

increasingly out of l ine with the rest of the ind ustry as the Inspectorate is

pleased to note that other companies have since amended their monitoring

programmes (see the Microbiological qual ity – Clostr idium perfr ingens

sect ion in Drinking water 2011 London and South East region ).

In 2011, Northumbrian Water detected Clostr idium perfr ingens in consumer

tap samples in January in the Sadberge, Burnhope pipel ine, Sunderland

Pal l ion, and Warkworth zones; in February in Whit ley Bay zone; and in

July in the Bedl ington and Stannington zone. United Uti l i t ies detected

Clostr idium perfr ingens in consumer tap samples collected in 2011 from

three zones: Haydock (February); Castle Carrock (March); and Rochdale

(November). Fol low-up samples by both companies were sat isfactory and

in the absence of any other information , the Inspectorate considers that

it is l ikely all of these failures were associated with local ised disturbances

of historic mains deposits. The companies did not carry out f it t ings

inspect ions at the propert ies to rule out any causative or other

irregular it ies in the bui lding water systems. The Inspectorate is cr it ical

of the approach of both companies towards monitor ing for this indicator

parameter.

In May, United Ut il i t ies detected Clostr idium perfr ingens in a sample

col lected f rom a concessionary supply of raw water f rom Damas Ghyl l

reservoir to a property in Quernmore, Lancashire. The sample taken was

also found to contain E.col i and coliform bacteria. There is a permanent

boi l water not ice in place for this supply because there is no point of use

treatment device instal led. The consumer has been provided with a

countertop ceramic f i l t rat ion unit , but there is no means of verifying that

the consumer is using the device, therefore the boil water not ice remains

in place. The company intends to connect the property to the mains as part

of a legally binding programme of work to improve concessionary suppl ies

throughout the company ’s supply area. This work is to be completed by

March 2013. The Inspectorate has put in place a Notice to require the

company to mit igate the r isk in the inter im.

Turbidity at works

Turbidity is a measure of how much l ight can pass through water and

indicates the condit ion or ‘cloudiness ’ of water. Turbidity is caused by

part ic les suspended in the water and is an important cr it ical control

measure of the performance of disinfect ion. Turbidity is measured at two

Northe rn reg ion

19

points in the water supply chain, at treatment works where a value of

1NTU appl ies and at consumers ’ taps where the standard of 4NTU appl ies.

The following discussion focuses on the results of samples taken at

treatment works.

In 2011, a total of 16 samples f rom treatment works in the Northern region

exhibited a turbidity value of >1NTU (1 DVW, 1 HPL, 4 NNE 4, 6 UUT,

4 YKS). This is an improvement over the 20 turbidity fail ures recorded

in 2010.

When a value of >1NTU was recorded in a sample f rom Warkworth works

in May, Northumbrian Water decided to instal l a turbidity monitor on the

northern main to provide addit ional information about water qual ity and

to improve knowledge about the potent ial impact of operational condit ions.

In response to a coli form failure in September , and a second elevated

turbidity value in October, the company identif ied a hydrant was being

used by contractors for jett ing act ivit ies . No check valve was f it ted, the

act ivity was stopped and an alternate water source for jett ing was

provided. The company also f lushed the sample l ines .

In May and September , turbidity values of >1NTU were recorded on three

occasions at Forest Farm works, near St Helens . United Ut i l i t ies abstracts

groundwater at this site which is pumped three kilometres to Winwick

service reservoir where it is blended with water f rom Winwick works .

The company found that the turbidity comprised part icles containing iron ,

manganese and lead and the stop-start of site pumps was mobil ising

sediment in the main supply ing water to the reservoir at Winwick. United

Uti l i t ies entered into a legal ly binding agreement to carry out remedial

work at the site to prevent further failures and secure compliance with the

requirements of Regulat ion 26. The planned improvements include the

instal lat ion of addit ional f i l t rat ion , variable speed drives for the borehole

pumps and turbidity monitor ing . The work was completed in March 2012.

In January, Yorkshire Water reported elevated turbidity at its Embsay

works near Skipton. A fault on a f low meter on a raw water main resulted

in f lows of water entering the works in excess of the design capacity of the

works. The company notif ied the Inspectorate of this event (see Annex 3).

The company were able to return the works to normal operat ion quickly.

The faulty f low meter was replaced in June 2011 and the site conf igurat ion

was altered to prevent a recurrence. Failsafe disinfect ion arrangements

wi l l be reassessed.

The Inspectorate was disappointed to note that more than one-third of the

turbidity failures in 2011 were f rom sites with a history of such problems

indicat ive of the industry’s general lack of due care and attent ion to this

important operat ional parameter.


20

Coliform bacteria at service reservoirs

Testing for coliform bacteria gives reassurance that the qual i ty of water

held at these strategic points in the distr ibut ion system is adequately

maintained. The national standard requires that at least 95% of no less

than 50 samples collected f rom each service reservoir throughout one year

are f ree f rom all coliform bacteria. In 2011, al l service reservoirs and water

towers (958) in the Northern region met the standard.

In June, col iform bacteria were detected at Northumbrian Water’s

Hemlington service reservoir (near Stockton -on-Tees). At the t ime of the

failure the west compartment was out of supply for inspection and repair

work and it was establ ished that the valves isolat ing the two cel ls were

shut. The west compartment was returned to service in June. The east

compartment was not taken out of service because it had been inspected

and repairs made in February. Low turnover was considered to be the

l ikely cause of the col iform failure and Northumbrian Water has taken

steps since to prevent a similar s ituat ion occurring again.

Northumbrian Water also detected coliform bacteria at Brandon service

reservoir (near Durham) in November. The company sampled widely in

response, including from consumers ’ taps and four related downstream

assets: reservoirs at Tunstall ; Frosterly; and High Woodif ield; and the

meter house at Rainton. Both compartments of Brandon reservoir had been

inspected in the summer with minor repairs made. The company scheduled

a further inspect ion to take place during 2012.

In December, Northumbrian Water were carrying out planned work to the

sample pumps at Hi l lheads reservoir (near Newcastle-upon-Tyne)

therefore the routine sample was col lected f rom an alternate location

(nearby consumer premises). Col iforms reported in this sample were

attr ibuted by the company to the condit ion of the tap. The Inspectorate has

had cause to be cr it ical of companies repeatedly for not putt ing in place

contingency arrangements for collect ing a representat ive sample whe n the

sampling facil i t ies at a site cannot be used. Examples of the adverse

consequences of taking service reservoir samples f rom downstream

consumers premises have appeared in Drinking Water 2010, 2009, 2008,

and 2004 .

United Ut i l i t ies carr ied out remedia l work in January 2012 af ter an

investigation at Ridley service reservoir (near Nantwich) , in response to a

col iform failure in November, identif ied ingress through the roof hatches.

When col iform bacteria were detected in a sample at Warbreck tower (near

Blackpool) in February, United Uti l i t ies identif ied a site of potential ingress

in the roof beneath some redundant monitoring equipment. The tower had

been inspected in 2008 using an underwater camera and from this the

condit ion was considered sat isfactory. The Inspectorate has become aware

Northe rn reg ion

21

of the industry’s increasing use of robotic equipment to inspect reservoirs

while st i l l ful l of water and in service. While such survei l lance is useful it is

not a subst itute for an internal inspect ion because it has l i mitat ions, for

example, ingress below the water l ine cannot be detected, as reported on

in the E.coli at works and service reservoirs sect ion of Drinking Water

2011 London and South East region report.

Yorkshire Water detected col iform bacteria at Market W eighton reservoir in

July and in a downstream asset, Arras service reservoir on the same day.

The inspection in August found points of ingress into the Market Weighton

reservoir through wall and roof ing joints during the f lood test . Repair work

was completed to one compartment dur ing October . The second

compartment was taken out of supply in November and returned to supply

in December af ter repair work . Once repairs at Market Weighton site had

been completed in December, Arras reservoir was taken out of supply for

inspect ion. Only minor remedial work s proved to be necessary and these

were completed by March 2012.

A sample in October f rom Carlecotes reservoir , near Barnsley, contained

col iform bacteria. The site had undergone major refurbishment in March,

therefore the Inspectorate was disappointed to note that the fai lure in

October was found by Yorkshire Water to be due to points of ingress where

new telemetry cables had since been instal led. A poor standard of work by

contractors instal l ing cables at service reservoirs is not a new problem for

Yorkshire Water (see Drinking water 2007) and this case suggests the

company has not put in place the learning. In part icular , the Inspectorate

has questioned if the company is ver ifying the work of contractors and

ensur ing public health is pr ior it ised over any other considerat ion when

works are specif ied. The company has since conf irmed that it intends to

make changes, specif ically to use one dedicated contractor and review

procedures for acceptance of remedial works as part of wider work to

understand the r is ing trend in coliform detect ions at its reservoirs. In 2011,

44% of coliform failures at service reservoirs across the Northern region

were at Yorkshire Water assets. The company has acknowledged this

maintenance problem and among other act ions has increased the

f requency of routine inspect ions and has deployed more engineers capable

of carrying out this type of work.

The Inspectorate has noted that col iform bacteria were found in 45

samples f rom service reservoirs in the Northern region during the year

and this information wi l l be taken into account in the planning of the

Inspectorate’s forward programme of r isk-based technical audit .

E.coli and Enterococci at consumers’ taps

A total of 36,966 consumers’ taps were tested in 2011 for E.coli and four

were posit ive (1 NNE, 2 UUT and 1 YKS). There was no indication, f rom


22

information gathered by the three water companies, of a faecal

contamination event affect ing other propert ies in these zones. Like E.coli ,

the presence of Enterococci is indicative of faecal contaminat ion and

neither bacter ium should be found in any sample. In 2011, all 2,987

samples were f ree f rom Enterococci.

When invest igating an E.coli fai lure f rom a consumer’s tap col lected f rom

a property in Leeds in Apri l, Yorkshire Water obtained evidence of tap

contamination. Microbiological swabs of the surfaces of the tap yielded

the same species of col iforms as those in the water sample. The consumer

was given advice about tap hygiene.

In June, Northumbrian Water detected E.col i in a sample taken from a

property in the North Tyneside zone. The company gave advice to the

consumer about tap hygiene af ter a f it t ings inspect ion found the consumer

tap in poor condit ion. Samples f rom neighbour ing propert ies proved

satisfactory and the checks at Horsley works found nothing untoward.

When invest igating an E.coli fai lure in a sample col lected in January f rom

a property in the Counthi l l zone (near Oldham) , the consumer informed

United Ut i l i t ies that they had exper ienced frozen pipes in the bungalow

during the recent cold weather . The company carr ied out a f it t ings

inspect ion at the property and provided the householder with a check valve

to ensure that domestic appl iances were isolated f rom the mains supply to

prevent back f low and gave advice on how to prevent a recurrence.

Chemical quality

The drinking water regulat ions set out the minimum test ing requirements

for all chemical and physical parameters. A full summary of the results

of test ing by each company, including the results for indicator parameters ,

is provided on the Inspectorate’s website and on the CD accompanying

this report.

The following text and Table 8 set out the results for those parameters

where there has been a failure to meet a European or na tional standard

(mandatory qual ity standards) and any other parameter of interest. In

addit ion, at the request of local author it ies, the results of test ing for

f luoride, iron, lead, manganese, nitrate, nitr ite, pesticides and radioact ivity

are given. New this year, the Inspectorate has included instances where

residual chlor ine results were reported at a level above that considered

desirable on grounds of consumer acceptabi l i ty (2mg/l).

Northe rn reg ion

23

Table 8: Chemical and physical parameters

The number of tests performed and the number of tests not meeting

the standard or screening value

Parameter

Current standard or

specified concentration

1

Total number of tests

Number of tests not meeting

the standard

4

Additional information

Aesthetic parameters

– colour 20mg/l Pt/Co

scale 13,300 1 UUT (1)

– odour No abnormal

change

10,392 42 NNE (1), UUT (37), YKS (4)

– taste 10,380 47 DVW (1), NNE (3), UUT (42), YKS (1)

Aluminium 200μg/l 13,192 9 NNE (4), UUT (3), YKS (2)

Benzo(a)pyrene 0.01μg/l 2,999 1 YKS (1)

Chlorine – residual (free)2 2mg/l 123,824 15 NNE (1), UUT (14)

Chlorine – residual (total)2 2mg/l 122,097 21 NNE (3), UUT (18)

Fluoride 1.5mg/l 2,965 0

Iron 200μg/l 13,190 43 NNE (12), UUT (15), YKS (16)

Lead (current standard) 25μg/l 2,984 3 NNE (2), UUT (1)

Lead (future standard) 10μg/l 2,984 22 NNE (5), UUT (11), YKS (6)

Manganese 50μg/l 13,181 9 DVW (1), NNE (2), UUT (4), YKS (2)

Nickel 20μg/l 2,983 5 NNE (3), UUT (2)

Nitrate 50mg/l 5,981 0

Nitrite 0.5mg/l 5,981 0

Pesticides – total 0.5μg/l 2,030 0

Pesticide – individual3 0.1μg/l 45,670 9

Chlortoluron YKS (1), Glyphosate UUT (1), MCPA UUT (1), Metaldehyde YKS (6)

Radioactivity

Gross alpha 0.1Bq/l 1,385 2 NNE (1), YKS (1)

Gross beta 1.0Bq/l 1,385 0

Tritium 100Bq/l 42 0

Sulphate 250mg SO4/l 1,899 4 NNE (4)

Turbidity (at consumers’ taps)

4NTU 13,314 5 NNE (3), UUT (1),

YKS (1)

Notes: 1For comparison, 1mg/l is one part in a million, 1μg/l is one part in a thousand million.

2The value of 2mg/l is a consumer acceptability value set by the Inspectorate.

3A further 3,934 tests were done for aldrin, dieldrin, heptachlor, heptachlor epoxide, all of which met the

relevant standard. 4Standard or screening value.


24

Aluminium

Aluminium can occur natural ly in some water sources. Also, aluminium-

based water treatment chemicals may be used at surface water works

to aid the process of f i l t rat ion.

In 2011, a total of 13,192 samples were tested for aluminium in the

Northern region. Dee Val ley Water and Hart lepool Water achieved 100%

compliance with the aluminium standard. Just nine tests exceeded the

standard (4 NNE, 3 UUT and 2 YKS) and in most cases these failures of

the aluminium standard were caused by localised disturbance of deposits

accumulated in the distr ibut ion network. Som etimes the failure was an

unavoidable consequence of planned work. On two occasions, other

standards ( iron, manganese and turbidity) were exceeded at the same

t ime.

In June, Yorkshire Water recorded an aluminium value of 213ug/l in a

sample collected f rom a consumer’s tap in the Hornsea 2004 zone, in East

Riding, Yorkshire. On investigation , the company identif ied treatment

performance issues at Tophi l l Low works. Turbidity in f i l tered water was

elevated, but within operat ional targets. Analysis of the part iculate matter

showed this to be aluminium and the company determined that water

leaving the works for a number of days had contained aluminium at a level

above the standard 200μg/l. The aluminium monitor at the works had not

been set up to record data trends or alarm in the control room. The

Inspectorate crit icised Yorkshire Water for not meeting the requirements of

Regulat ion 26 at Tophi l l works (failure to design and continuously operate

an adequate treatment process) because once the problem was identif ied,

the company did not notify the situat ion as a water qual ity event.

The Inspectorate considers that companies in the Northern region need

to improve r isk assessment and r isk management in relat ion to zones

exhibit ing repeated aluminium failures in con sumer tap samples. For

example, there have been three failures in recent years in United Uti l i t ies’

Walkden zone, notably in 2008 when Lostock Works experienced a

malfunction of dosing equipment result ing in elevated levels of aluminium

entering the distr ibut ion system causing fai lures at consumers’ taps. The

Inspectorate expects companies to proact ively review and update

regulatory r isk assessments using al l relevant routine and investigational

aluminium monitoring data ensuring that the crit ical controls at treatment

works are adequate and formally documented.

Colour

Colour occurs naturally in upland water sources. I t is removed by

conventional water treatment . The condit ion of water mains and bui lding

water systems can also give r isk to local ised failur es of the standard for

Northe rn reg ion

25

colour. A nat ional standard of 20mg/l on the Plat inum/Cobalt (Pt/Co)

scale appl ies.

Across the Northern region in 2011, out of 13,300 tests there was a single

failure of the standard for colour (1 UUT).

In June, a value for colour of 27.3mg/l was recorded in a sample col lected

f rom a property near Oswestry that received a concessionary (f ree) supply

of raw water provided by United Uti l i t ies. The raw water came from the

Vyrnwy aqueduct and there was a point -of-use treatment device ins tal led

at the property. The property has subsequently been connected to the

mains as part of a legally binding program of works to improve the qual ity

of concessionary suppl ies across United Uti l i t ies ’ supply area.

Chlorine

Chlorine is widely used in households as bleach. I t is an important

dis infectant with many appl icat ions in the home and workplace wherever

the maintenance of good hygiene is necessary. I t is the most common

oxidative dis infectant used in swimming pools and there is a long history

of i ts use in water suppl ies stretching back for a century. Typical levels

of residual chlor ine in public water suppl ies in the UK are in the range of

0.1 – 1.0mg/l, wel l below levels typical ly found in many other parts of the

world. Human exposure to chlorine in drinking water has not been

associated with any specif ic adverse health ef fects and the World Health

Organisation’s (WHO) health-related guidel ine value for chlorine is set at

5mg/l.

There is not a numerical standard for residual chlor ine in dr inking water

in England, however, water companies are required to measure residual

chlorine whenever they are collect ing samples for microbiological analysis

and any abnormal change in chlor ine concentrat ion must be investigated.

In addit ion, water companies are expected to have regard to consumer

acceptabi l i ty by investigating chlorine -related taste and odour complaints

f rom consumers. The Inspectorate has set a screening value of 2mg/l for

the purpose of assessing the effect iveness of residual chlorine

management by water companies.

Chlorine was recorded at a level greater than 2mg/l on 21 occasions

across the Northern region dur ing 2011 (3 NNE, 18 UUT).

In December, Northumbrian Water recorded a chlor ine residual of 2.2mg/l

at Lart ington works (near Barnard Castle, Durham) at a t ime when

emergency chlorine dosing was being carr ied out in response to an event

at the works caused by a damaged and part ially blocked coagulant dosing

l ine. There was one consumer complaint of an unusual taste and odour

during this event (see Annex 3).


26

United Ut i l i t ies recorded chlor ine greater than 2mg/l on 18 occasions

during 2011. In February, a value of 4.76mg/l was recorded in a sample at

Adl ington No2 works and on investigation the company found a fault with a

monitor which was rect if ied. Companies are reminded of the importance of

proactively maintaining and cal ibrat ing monitors and instruments at works

ensur ing these are designated as crit ical control points, as required by the

water safety plan approach to safeguarding water q uality.

In September, a chlorine residual of 3.6mg/l was recorded by United

Uti l i t ies in a consumer’s tap sample collected f rom a property in the

Bamber Br idge zone (Blackburn , Preston area). Following an enquiry by

the Inspectorate the company identif ied a transcript ion error in the data

return, the actual value was 0.36mg/l. Companies are reminded of the

importance of carrying out thorough checks of the accuracy of data returns

before submitt ing these to the Inspectorate.

Chlorine values ranging f rom 2.03mg/l to 2.40mg/l were recorded in seven

samples f rom Prescot New works (near Huyton , Merseyside) between

January and November. Fol lowing an enquiry by the Inspectorate, United

Uti l i ies explained that water leaving this works is blended before

consumers receive it . Prescot New works supplies 16 zones and the

Inspectorate has noted that there were 10 consumer complaints in these

zones about chlor inous tastes or odours during the period when residual

chlorine values leaving the works exceeded 2mg/l. United Ut i l i t ies was

reminded of the need to review its residual chlor ine policy and pract ices ,

part icularly when distr ibut ion improvement programmes have been carr ied

out and more stable residual chlorine is to be expected as a consequence.

At each works and at booster equipment in the distr ibut ion system, there

should be a documented target for residual chlorine and associated crit ical

controls and companies are reminded that these must be reviewed on a

regular basis to ensure they remain appropriate and water qua l ity is

acceptable to consumers.

Disinfection by-products

To ensure the microbiological safety of publ ic water suppl ies , water

companies are required to dis infect water at the treatment works before

supplying it through the distr ibut ion system to consume rs. Disinfect ion

may be achieved by any appropr iate physical or chemical method, or a

combination of the two. The choice of method wil l depend on a range of

site-specif ic factors, but an important considerat ion is the requirement to

keep disinfect ion by-products (DBPs) to a minimum. This 1998 EU Drinking

Water Direct ive requirement was introduced formally into nat ional law in

2010 in January 2010.

Northe rn reg ion

27

Chemical disinfectants are powerful oxidants that react with organic and

inorganic matter in raw water to form other compounds known as DBPs.

There are many dif ferent DBPs and the l ikelihood of any part icular ones

occurring in a given water supply can be predicted f rom the raw water

quality and the method of disinfect ion. A summary of commonly

encountered DBPs can be found in the WHO Guidel ines for Drinking Water

Qual ity 2004 , Sect ion 8.5.4. Based on current global research it is felt that

two groups of compounds, tr ihalomethanes (THMs) and haloaceticacids

(HAAs), serve as adequate indicators for monitor ing DBP performance

overall. The most appropriate means of control l ing DBPs is the removal

of the organic precursors f rom the raw water before it is disinfected.

The Inspectorate has made a preliminary assessment of how well

companies in the Northern region are meet ing the DBP rule using water

company THM data reported for 2011. For this init ia l evaluation, the

Inspectorate has set a screening criter ion of an annual average value

of <50µg/l (50% of the THM standard) as a broad indicator that general ly

a company is minimising DBPs ef fect ively. Table 9 shows that four zones

in the region exceeded this screening cri terion ( 1 DVW, 1 NNE, 2 YKS).

The Inspectorate expects companies to review the r isk assessment for

each of these suppl ies with specif ic reference to compli ance with

Regulat ion 26 (as amended in 2010). Where the need for addit ional control

measures are identif ied, then companies should submit a Regulat ion 28

report to the Inspectorate, with proposals for an act ion plan for any

necessary steps to be taken.

Table 9: Numbers and names of zones exceeding an annual average

for trihalomethanes of >50µg/l

Company

Number of zones

operated by company

Number of zones exhibit ing an annual

average for trihalomethanes >50µg/l

Name of zones exhibit ing an annual

average for trihalomethanes

>50µg/ l

Dee Val ley Water

18 1 Old W arren

Har t lepool Water

3 0 -


75 1 Bedl ington and Stannington

Peel Water Networks

1 0 -


230 0 -

Yorkshire Water

76 2 Manor Bradford SW

Industry total 1,670 37 -

Note: Figures are for whole company areas .


28

Fluoride

Traces of f luoride occur naturally in many water sources, part icularly in

groundwaters. For example, naturally occurring f luoride is found in the

Hart lepool and Easington area where water is drawn from the l imestone

aquifer. Consumers can obtain specif ic information on the level of f luoride

in the dr inking water supply to their home or workplace f rom their water

company.

Fluoride is not removed by conventional water treatment. Some companies

f luoridate water suppl ies when required to do so by the local public health

author ity as a protect ion against tooth decay. Fluor ide is added on this

basis to water suppl ied by Northumbrian Water and United Ut i l i t ies. In

2011, al l 2,965 tests for f luoride taken across the region met the

regulatory standard (1.5mg/l). Please refer to the Inspectorate’s website

(www.dwi.gov.uk) for more information on f luoridat ion.

On 11 February 2011, the judicial review brought against South Central

Strategic Health Authority (SCSHA) by Geraldine Milner was concluded.

The review was about whether the SCSHA followed the correct procedure

when deciding to f luoridate the Southampton and South West Hampshire

area. The judge found in favour of the SCSHA and technical feasibi l i ty

of the f luoridation arrangements are being f inal ised. No new f luor idation

schemes were taken forward in the Northern region in 2011.

Geosmin and methyl-isoborneol

Geosmin and methyl- isoborneol are substances produced by the seasonal

growth of algae, in s low moving surface water. They give r ise to a

character ist ic ‘earthy’ or ‘musty’ taste and odour discern ib le to consumers.

During 2011 there were no posit ive detect ions of taste and odour in

consumer tap samples col lected in the Northern region attr ibutable direct ly

to geosmin and methyl- isoborneol. However, during the year, United

Uti l i t ies reported an earthy or musty taste or odour in 14 tests in two zones

(Watergrove (13) and Lancaster (1)) where there are legal ly binding

agreements in place to improve three treatment works (Piethorne,

Lancaster and Watergrove) due to an unacceptable r isk f rom geosmin and

methyl- isoborneol. When completed on or before July 2014 , these

improvements involving the installat ion of granular act ivated carbon in

exist ing sand f i l ters wi l l improve water qual ity for over 335,000 consumers.

The Inspectorate has noted that there were operat ional problems (blocking

of powdered act ivated carbon dosing l ines) with the temporary control

measure at Watergrove works during August and September.

Northe rn reg ion

29

In 2011, there were another 35 tests (34 UUT, 1 NNE) that exhibited an

earthy/musty/mouldy taste where the company investigation did not

establish the cause. Two zones, Ashton East and Stalybr idge operated

by United Uti l i t ies had four and f ive taste or odour detect ions respect ively

in one year. The Inspectorate expects companies to improve their

investigations where there are mult iple detect ions in one year.

When consumers experience a persistent taste or odour, they may contact

their water company to report the problem. Records of these contacts in

each zone are recorded by water companies and passed to the

Inspectorate annually. Figure 10 shows the contact rate per thousand

people across the Northern region and the location of taste and odour

detect ions where the cause was not attr ibuted to arrangements within

premises.

Figure 10: Rate of taste and odour contacts per 1,000 population


30

Nitrate and nitrite

Nitrate occurs natural ly in all source waters due to the decay of vegetable

material in soil. Nitrogenous fert i l isers used on arable farmland are a

signif icant source of nitrate in groundwater. Rainfall washes nitrate f rom

the soi l into lakes, r ivers and streams. Nitrate levels can be reduced by

water treatment or by blending with another, low nitrate, water source.

In 2011, across the Northern region, all tests for nitrate met the standard

(50mg/l).

From extensive information gathered by the water companies, a l ikelihood

of drinking water suppl ies in the region fail ing the nitrate standard in the

longer term has been conf irmed at some sites. As a consequence, legally

binding agreements are in place for addit ional treatment, if required, at

Yorkshire Water’s Tophi l l Low works . These improvements are scheduled

to be commissioned in March 2015 and wil l improve water quality for

around 260,000 people in the Hull, Beverley, Hornsea and Holderness

areas.

Nitr ite may be formed when chloramine is used as the residual dis infectant

to maintain the microbiological qual ity in the distr ibut ion network. The

formation of ni tr ite is control led by careful opt imisation of the

chloramination process. A few supplies in the Northern region contain a

chloramine residual . Northumbrian Water uses chloramine in the Middleton

in Tees area (Lart ington works). Yorkshire Water suppl ies water with a

chloramine residual to consumers in the Doncaster, Skipton, Whitby, York

and Pateley Br idge areas f rom the following works: Nutwell ; Embsay;

Ruswarp; Acomb Landing; Harlow Hil l works outlet to Pateley Br idge; and

Elvington works outlet to Siwards. Nitr ite can also form in samples of

water, af ter collect ion and before analysis, especially if the sample is not

kept cool.

In 2011, al l 5,981 tests carr ied out across the Northern region for nitr ite

met the standard.

Pesticides and related products

This group of substances, generically cal led pesticides, includes many

organic chemicals ranging from weed kil lers, to insectic ides and

fungicides. Water sources may contain traces of pestic ide residues as a

result of agricultural use (pest control on crop s) and non-agricultural use

(herbicides for weed control on highways, railways etc.). Water companies

are required to assess the r isk to drinking water supplies of pestic ide use

in source water catchments and then test for those that might be present.

Companies have documented potential and actual pest ic ide hazards

through their r isk assessments as informed by raw water monitoring. When

pestic ides are f irst detected, water companies wi l l enhance the monitoring

Northe rn reg ion

31

of raw water and not ify the Environment Agency to facil i tate appropr iate

act ion in the catchment to safeguard drinking water quality.

In 2011, none of the tests in the region exceeded the standard for total

pestic ides. There was 100% compliance (3,934 tests) for the four

pestic ides with a standard of 0.03μg/l. Out of a total of 45,670 tests for

those individual pest ic ides with a standard of 0.1μg/l j ust nine exceeded

the standard. The circumstances and substances involved are summarised

below.

Chlortoluron

Chlortoluron is a herbicide for use in winter cereal crops. The standard

is 0.1μg/l.

Chlortoluron at a level of 0.205µg/l was detected in a sample in December

col lected f rom Irton works, near Scarborough, operated by Yorkshire

Water. Follow-up samples were sat isfactory. The company are

investigating hydraul ic arrangements in the catchment to identify the

origins of the apparently short l ived and intermittent episodes of pesticide

contamination of the raw water source. The Inspectorate recommended

that the company reviewed and updated the site r isk assessment to take

into account this failure and to provide detai ls of the short-, medium- and

long-term controls in place to prevent a recurrence. Subsequently the

company have revised the r isk assessment for the source water at Ir ton

works and have included chlortoluron in their catchment act ion plan.

Glyphosate

Glyphosate is a non-select ive herbicide for control of annual and perennial

weeds in non-crop situations and is used extensively by gardeners . The

standard is 0.1µg/l.

In December, glyphosate was detected at a level of 0.248μg/l in a sample

f rom United Uti l i t ies’ Hurleston works near Crewe. Follow-up sampling

found no further evidence of this substance at the works or in the raw

water, which comes from Llangollen canal . Enquir ies of catchment

stakeholders did not identify any glyphosate usage along the canal banks

at the t ime. The company has put in place weekly glyphosate monitor ing

of the raw water to provide more information about this potent ial emerging

r isk.

MCPA

MCPA is a herbicide f requently found with other herbicide s. I t is mainly

used for weed control in lawns, amenity agriculture and cereals. The

standard is 0.1μg/l.

In July, when MCPA was detected at a level of 0.14μg/l in a sample f rom

United Uti l i t ies’ Wayoh works, near Bolton, it was notif ied to the


32

Inspectorate as a water quality event (see Annex 3). Forest off icers in a

non-catchment area identif ied the use of MCPA on dock leaf plants and

thist les following the company’s use of aerial survei l lance to search for

areas of interest . Powdered act ivated carbon (PAC) was dosed at the

works to reduce the level in the raw water. The Inspectorate was pleased

to note this example of collaborative working with stakeholders to track

and manage catchment r isks.

Metaldehyde

Metaldehyde is the act ive ingredient in some slug pel lets. The standard

is 0.1µg/l.

Yorkshire Water reported six fai lures of metaldehyde dur ing October and

the levels found in consumers’ taps in the zones affected were as follows:

Thrybergh 2004 (0.16µg/l) ; Rotherham 2008 (0.157µg/l) ; Aughton 2004

(0.177µg/l) ; Ardsley 2004 (0.214µg/l) ; and Leeds HI Cross Gates/Scholes

2004 (0.225µg/l). Another failure occurred in November at the Brayton

Barff supply point (0.17µg/l). As part of a legal ly binding agreement,

Yorkshire Water has catchment management schemes in place to

investigate and minimise the occurrence of metaldehyde in the raw water

sources to the six treatment works supplying these zones . Figure 11 shows

the average raw water metaldehyde value at the relevant abstract ion

points over three years. The schemes wil l be completed in March 2014.

Northe rn reg ion

33

Figure 11: Average raw water metaldehyde value (µg/l) at abstraction

points 2009–2011

Radioactivity

Gross alpha/gross beta/total indicative dose

Radioactivity in raw water can originate f rom natural substances or f rom

a specif ic point emission. Water companies are required to screen for

radionucl ides that emit either alpha or beta part ic les. I f such screening

exceeds guide values (gross alpha 0.1Bq/l, gross beta 1.0Bq/l) , then fuller

analysis for specif ic radionucl ides is carr ied out to determine the origin.

Total indicat ive dose (TID) is a measure of the effect ive dose of radiat ion

through consumpt ion of the water. The guide value is 0.1mSv/year.

In 2011, out of 2,770 tests in the Northern region, there were two

detect ions of gross alpha above screening value. One occurred in the

Doncaster Rural 2004 zone (YKS) in February and one at Ful lwell supply

point (NNE) in September .

Northumbrian Water carr ied out enhanced monitor ing in response to the

gross alpha value recorded at Ful lwell supply point and found that levels

were exceeded only intermittently. Addit ionally , monitor ing by Yorkshire

0.000.050.100.150.200.250.300.350.400.450.50

Ec

cu

p N

o 1

(W

ash

bu

rn)

Ec

cu

p N

o 2

(O

use

)

Elv

ing

ton

Ew

de

n

He

ad

ing

ly N

o 2

Ing

bir

ch

wo

rth

2 (

Ro

yd

Mo

or)

Ing

bir

ch

wo

rth

2 (

Ing

bir

ch

)

La

ng

sett

No

2 (

La

ng

sett

)

Lo

ftso

me

Bri

dg

e

Lo

xle

y C

om

bin

ed

Riv

eli

n N

o 2

(D

erw

en

t)

Riv

eli

n N

o 2

(R

ive

lin

)

YKS

2009 2010 2011

0.1µg/ l i s the s tandard for meta ldehyde in dr i nk ing wate r .


34

Water showed levels in the Doncaster zone were below the screening

value and der ived f rom the under lying rock strata.

Tritium

Monitor ing for tr it ium is necessary only where a source of tr it ium is present

within the catchment and it cannot be shown on the basis of other

surveil lance programmes or investigations that the level of tr it ium is well

below its parametr ic ind icator value of 100Bq/l.

United Ut i l i t ies carr ied out tr it ium monitoring during 2011 and al l 42 tests

gave results below the indicator value of 100Bq/l.

Sulphate

The level of natural ly occurring sulphates in water is highly variable and

normally ref lects the local geology with greater amounts tending to be

found in brown coal regions and in salt areas. The f inding of an increased

level of sulphates, along with chlor ides, can also indicate human pollut ion

of a water source. Waters of natural ly high sulphate content, part icularly

alkal i and magnesium sulphates, act as a purgative. Even relat ively small

amounts may cause a temporary disturbance to the normal intest inal

function. Higher levels have a tendency to cause diarrhoea, especially

among chi ldren. The standard of 250mg/l is set to avoid these concerns

and to assist with the select ion of suitable sources of drinking water.

In 2011, there were four failures to meet the standard of 250mg/l out of

1,899 tests across the Northern region (4 NNE).

The Health Protect ion Agency have advised Northumbrian Water that

the levels of sulphate found in the summer months in three zones in

Sunderland do not pose a r isk to the health of the populat ion. The source

of water is the River Wear which is seasonal ly af fected by sulphate

washout f rom local mines. The control measure in place is blending with

low sulphate water f rom another works (Stoneygate). In 2011 , the

maximum value of sulphate reported in c onsumer tap samples was

300mg/l. The Inspectorate expects Northumbrian Water to use monitor ing

data to update its r isk assessment and optimise blending controls.

Northe rn reg ion

35

Maintaining water quality in distribution

Elevated levels of iron or manganese are object ionable to consumers

because the water may appear turbid or discoloured due to unsightly

deposits and may also stain laundry and water f it t ings. Since 2004 , the

Inspectorate has been monitor ing the progress of companies’ distr ibut ion

maintenance work, using an index made up of three parameters (turbidity,

iron and manganese). Figure 12 shows the long-term improvements in the

Northern region. In 2011, most company f igures improved, the except ion

was Dee Val ley Water , where an increase in failures was reported in the

Welsh supply zones.

Figure 12: Percentage of tests meeting the standards for turbidity,

iron and manganese

99.20

99.30

99.40

99.50

99.60

99.70

99.80

99.90

100.00

2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011

Pe

rce

nta

ge

me

eti

ng

sta

nd

ard

Northern

Dee Valley Water Hartlepool Water Northumbrian Water

United Utilities Yorkshire Water

Note: Pee l W ater Networks on l y began supp l y i ng in 2009. They ach ieved 91.67% in 2009 and

100% in 2010 and 2011 .

Discolourat ion of tap water of ten prompts consumers to contact their water

company. The number of people contact ing water companies about

discoloured water is reported annual ly to the Inspectorate in accordance

with Information Letter 1/2006. Looking at the trend since 2007, it can be

seen from Figure 13 that across the industry, the numbers of consumers

contact ing their water company to complain about discoloured water has

fallen f rom nearly 84,000 to below 54,000. In the Northern region, the

reduction is more pronounced with the f igure now standing at just under

35,000, down 40% since 2007. These consumer contacts represent one-

third of all consumer contacts to the industry regarding discolourat ion.


36

Figure 13: Consumer contacts to companies for discolouration

2007–2011

0

10,000

20,000

30,000

40,000

50,000

60,000

70,000

80,000

90,000

2007 2008 2009 2010 2011

Northern region

Rest of Industry

Looking more closely at the Northern region, mapping of the rate of

consumer contacts by zone shows the changing picture f rom 2007 – 2011.

Rates of consumer contacts to companies about discoloured water in 2007

(Figure 14) i l lustrates the situation before del ivery of the AMP4

improvement work by companies. Figure 15 shows the comparable rate at

the end of 2011 af ter complet ion of the AMP4 investment.

These maps show the benef it of work completed by Northumbrian Water

across 61 zones, which has improved water quality to near ly two mill ion

consumers. This is part icular ly not iceable in the Newcastle area, where

work to improve consumer acceptabil i ty was completed in March.

United Ut i l i t ies completed two schemes during 2011, involving 17 zones

and benef it ing over 645,000 consumers, part icularly those l iving in the

Blackpool and Preston areas. Similar improvement work was completed in

September by Yorkshire Water in three zones in the Rivel in area , near

Sheff ield, improving water qual ity for nearly 240,000 consumers.

The overal l reduction in consumer contacts about discolourat ion across the

Northern region is also ref lected in a fall in the number of tests fail ing the

iron standard during 2011 from 62 in 2010 to 43 in 2011.

Northe rn reg ion

37

Figure 14: Rate of consumer contacts per 1,000 population reporting

black, brown or orange water in 2007


38

Figure 15: Rate of consumer contacts per 1,000 population reporting

black, brown or orange water in 2011

The monitoring results for iron, manganese, turbidity and polycycl ic

aromatic hydrocarbons (PAHs) across the Northern region in 2011 are

summarised below.

Dee Val ley Water recorded a single failure of the manganese standard and

Hart lepool Water reported 100% compliance with al l four standards.

In the area supplied by Northumbrian Water there were 17 samples which

exceeded the standards: iron (12); manganese (2); and turbidity (3).

In most instances, the cause was a local ised disturbance of mains

Northe rn reg ion

39

deposits dealt with by f lushing. Nine of the failures were in zones covered

by a legally binding agreement to carry out mains replacement or cleaning

in the Tyneside and Wearside areas, due for complet ion between Apri l

2013 and March 2015.

United Ut i l i t ies recorded 20 fai lures during 2011: iron (15) ; manganese (4) ;

and turbidity (1). Twelve of these failures were located in zones where the

company is carrying out work to improve water qual ity in distr ibut ion and

these legal ly binding schemes are due for complet ion by 2014 and 2015

benef it ing in excess of 1.5 mil l ion consumers across the United Uti l i t ies

supply system.

When invest igating an iron fai lure at a consumer’s tap in the Ashworth

Moor zone in September, United Ut il i t ies found that a treatment problem

had been occurring at Ashworth Moor works during the preceding month

leading to a slight elevation in the iron concentrat ions enter ing the contact

tank. An iron failure in Stalybridge in September was l inked to a burst on

the 12 inch diameter main in High Street, Dukinf ield which caused f lows

to increase, with 70 consumers report ing low pressure or loss of supply .

Yorkshire Water reported 20 failures in 2011: iron (16); manganese (2);

turbidity (1); and PAHs (1). Three failures were in the Leeds HI Cross

Gates/Scholes zone covered by a legal ly binding distr ibut ion improvement

programme cover ing 67 zones and which was due for complet ion in March

2010, this work is await ing post complet ion assessment.

Fol lowing an iron failure in the Keighley zone in July, Yorkshire Water took

samples dur ing a hydrant f lush conf irming the need for a programme of

routine f lushing to be put in place for the local main.

In October, Yorkshire Water detected benzo(a)pyrene at a level of

0.0106µg/l at a property in the Holderness 2008 zone near Hull. The

company established this was l inked to a burst on a bitumen- l ined iron

main and f lushing was carr ied out. A fol low-up sample in December

was sat isfactory.

The Inspectorate has noted that half the iron fai lures in 2011 were

reported in zones where there had been iron failures in previous years.

The Inspectorate considers that all companies in the region should be

using this information to put in place proactive r isk management and

medium-term control measures pr ior to complet ion of long -term distr ibut ion

improvements and review monitoring data to ident ify where there is no

long-term strategy in place for any zone exhibit ing year on ye ar failures.

Annex 4 detai ls the legally binding programmes of distr ibut ion

maintenance work scheduled to be completed between now and 2015

to address ongoing distr ibut ion qual ity problems in the region.


40

Maintaining water quality at the tap

Consumers expect their dr inking water to be clear and bright in

appearance and free from discernible taste , odour or contaminants.

Several parameters are not rout inely found in mains water , but instead

they gain access to tap water c lose to the point of use. For exampl e,

certain plumbing metals (ant imony, copper, lead and nickel) and sodium

introduced by water sof teners instal led in premises. Accordingly ,

remediat ion of failures for these parameters requires act ion to be taken

by property owners.

Table 16: Failures in samples collected from taps where the cause was

attributed to the premises

Parameter

De

e V

all

ey

Wa

ter

Ha

rtle

po

ol

Wa

ter

No

rth

um

bri

an

Wa

ter

Pe

el

Wa

ter

Ne

two

rks

Un

ite

d U

tili

tie

s

Yo

rks

hir

e W

ate

r

Metals

Ant imony 0–36 0–20 0–545 0–4 0–1,786 0–575

Copper 0–36 0–20 0–545 0–4 0–1,803 0–575

Lead >10 0–36 0–20 5–545 0–4 11–1,804 6–575

Nickel 0–36 0–20 0–545 0–4 0–1,803 0–575

Colour 0–101 0–40 0–2,384 0–4 0–6,873 0–3,898

Conduct ivi ty 0–221 0–40 0–2,384 0–4 0–3,546 0–3,898

Odour 0–101 0–40 1–1,304 0–4 2–5,044 3–3,899

pH 0–100 0–40 0–2,384 0–4 0–6,879 0–3,898

Sodium 0–36 0–20 0–545 0–4 0–6,782 0–575

Taste 1–101 0–40 2–1,304 0–4 3–5,034 0–3,897

Total 1–804 0–300 8–12,485 0–40 16–41,354 9–22,365

Note: Fa i lu res counted i n th is tab le are those cau sed by cond i t ions or ar rangements in the prem ises

Table 16 i l lustrates the distr ibut ion of failures for the parameters aris ing

within al l types of premises across the region. Overal l in the Northern

region in 2011, there were 22 fai lures of the standards for metals (5 NNE,

11 UUT, 6 YKS) and 12 posit ive detect ions for taste and odour (1 DVW, 3

NNE, 5 UUT, 3 YKS).

Northe rn reg ion

41

In al l such cases the company must advise consumers of the fai lure and its

cause with information about the act ions needed to safeguard health in the

short term, as wel l as what is needed to effect a remedy in the longer

term. If the failure occurs in a publ ic bui lding, the company must go further

and, either alone or act ing in col laborat ion with the local authority, enforce

act ion by the relevant persons.

Table 17 shows the number of invest igations in publ ic bui ldings result ing

f rom a failure of a standard or exceedance of an indicator parameter

value. In 2011, there were ten failures of standards in publ ic bui ldings

in the Northern region and the circumstances are discussed below.

Table 17: Investigations in public buildings where action is required

by building owners

Company Total tests at

consumers’ taps

Total tests at publ ic buildings

Investigat ions in public buildings

Dee Val ley W ater 4,397 0 0

Har t lepool Water 1,981 12 0


76,324 2,639 2

Peel Water Networks

458 0 0

Uni ted Ut i l i t ies 211,079 4,415 7

Yorkshire W ater 157,277 6,205 1

Total 451,516 13,271 10

Lead

The most common source of lead in tap water is pipework in stal led before

the 1970s or the use of non-approved solder on cold water systems. Lead

may also leach f rom brass f it t ings. The standard of 10µg/l comes into force

at the end of 2013, but the Inspectorate has strongly recommended that

companies take act ion ahead of the new standard coming into force

(Guidance on the Implementation of the Water Supply (Water Quality)

Regulat ions 2000 – Regulat ion 30).

In 2011, companies in the region identif ied 22 failures (5 NNE, 11 UUT,

6 YKS) of the future standard of 10µg/l f rom a total of 2,984 tests.

As shown in F igure 18, the situat ion regarding lead in the region is

marginal ly better than the f igure for the industry overal l .


42

Figure 18: Percentage of tests meeting the future standard of 10µg/l

for lead between 2002 and 2011

92

93

94

95

96

97

98

99

100

2002 2003 2004 2005 2006 2007 2008 2009 2010 2011

Perc

en

tag

e m

eeting

sta

ndar

d

10ug/l Industry 10ug/l Regional

Al l zones where samples exceeded 10µg/l receive phosphate dosing which

results in a protect ive layer inside pipework minimising the release of lead

into tap water. Lead above 10µg/l was not found in samples f rom any

public building in the region.

In 2011, the Inspectorate commissioned research with the water industry

research organisat ion (UKWIR) to look beyond the current water treatment

measures now in place to reduce exposure to lead f rom tap water. The

study looked at a wide range of quantit at ive and qual itat ive data , including

the est imated number of propert ies with lead pipes in the UK, lead in tap

water measurements, and the costs and benef its of measures such as

water treatment and supply pipe and service pipe replacement. One output

of the project is an economic tool that enables users to est imate the costs

and benef its of basel ine phosphate dosing alongside the alternatives of

lead pipe replacement or rehabil itat ion. Wider impacts were also

considered, including consequential wastewater treatment costs, carbon

emissions, health and other benef its such as reduct ions in copp er

concentrat ions in tap water.

The publ ished UKWIR report , Alternat ives to phosphate for

plumbosolvency control (12/DW/04/12), concluded there is no pract ical

alternative water treatment measure to the phosphate dosing regime

already in place and this was conf irmed as being effect ive in reducing lead

concentrat ions in tap water very substant ial ly. The report also makes clear

how replacement of a water company supply pipe wi l l not result in a

signif icant reduct ion in r isk of exposure to lead , unless the customer

service pipe is also replaced at the same t ime. The research has identif ied

addit ional benef its attr ibutable to phosphate dosing in the form of reduced

amounts of copper leaching f rom plumbing and a similar ef fect in relat ion

Northe rn reg ion

43

to iron concentrat ions. Pipe rel ining as an alternative to lead pipe

replacement is also discussed in the UKWIR report. Early test ing of this

approach did not result in rel ining being widely ap pl ied by the industry,

however, a new rel ining method has been developed which is potent ially

more cost benef icial and this is current ly undergoing tr ials. The f indings

of this research wi l l be taken into account in water company strategies

for minimising exposure to lead in the long term.

Aesthetic parameters

Aesthet ic parameters are the measurement of colour, odour and taste.

In 2011, a total of 89 samples f rom consumers’ taps in the region exhibited

a posit ive taste or odour. The posit ive detect ions of taste and odour

attr ibuted to condit ions in premises are summarised below in relat ion to

their nature and cause as determined by the investigat ions carr ied out by

the companies.

Earthy/musty

Yorkshire Water detected a musty/sulphide odour in a sample t aken from

the York East zone. A f it t ings inspection at the consumer’s property

identif ied a length of grey PVC hose which was probably responsible for

the odour. A check valve was subsequent ly f it ted and advice provided to

the householder.

A consumer tap sample taken in Apr i l f rom the Esk Val ley zone near

Whitby, North Yorkshire was found to have a yeasty/musty odour. Follow-

up samples col lected by Yorkshire Water were sat isfactory, however, the

company did not carry out a f it t ings inspection so there is n o conclusive

evidence that the problem was related to fungal growth attr ibutable to the

bui lding water system.

Pencil taste

This descr iptor is specif ic to a substance associated with unapproved ,

black, plast ic pipe. Two samples (1 NNE, 1 UUT) were identif ied as having

a penci l taste and odour out of 20,772 (10,380 taste, 10,392 odour) taken

in the region in 2011.

In October, a penci l taste and odour was identif ied in a consumer’s tap

sample collected f rom the Rochester zone, in Northumberland. Despite the

diagnost ic nature of this descriptor , Northumbrian Water failed to conf irm

the presence of an unapproved pipe.

United Ut i l i t ies identi f ied a penci l taste in a consumer’s tap sample taken

from a property in the Bamber Br idge zone, near Samlesbury in

Lancashire. A visual inspect ion of the supply arrangements found that the

consumer ’s supply pipe was made of black alk athene and the company

communication pipe was part lead and part black alkathene. The company


44

replaced the communication pipe in December and further tests were

satisfactory.

Bitter/metallic

These descr iptors usual ly relate to samples where the tap water is

art if icial ly sof tened or where levels of plumbing metals, such as copper ,

zinc or iron are elevated.

In Apri l , a sample collected f rom a consumer’s tap in the Spennymoor

zone, near Durham exhibited a bit ter/metal l ic taste. Northumbrian Water

carr ied out a f it t ings inspect ion and found nothing untoward. Fol low-up

samples at the same and neighbour ing propert ies were f ree f rom taste and

odour. The Inspectorate expects company investigations to be guided by

the descr iptor in relat ion to the analysis carr ied out on follow -up samples,

for example, a bit ter/metal l ic taste should prompt test ing for metals.

Solvent/petrol/hydrocarbons

These descr iptors re late to situat ions where there has been a spi l lage

of central heat ing oi l , petrol or diesel on the premises and this has gained

access to the drinking water supply , usually, but not exclusively, due to

permeation of the underground plast ic supply pipes.

Three samples were identif ied as having a solvent/petrol /hydrocarbon

taste and odour (2 UUT, 1 YKS) out of 20,772 (10,380 taste, 10,392 odour)

taken in the region in 2011.

In December, a petroleum/solvent taste and odour was ident i f ied in a

consumer’s tap sample col lected f rom a property in the Alsager zone, near

Crewe. Further samples col lected by United Uti l i t ies were f ree from taste

and odour. Organics analysis ruled out any spi l lage of fuel , but detected

traces of 2,6-diisopropylnaphthene, commonly used as a preservative for

potatoes, in a sample taken from a neighbour ing property. This substance

is odour less and poses no r isk to human health at the low concentrat ion

detected. The company believes the detect ion of 2,6 -di isopropylnaphthene

was incidental and the extremely low levels found did not warrant further

investigation. The Inspectorate is in dialogue with the company about its

approach towards investigating posit ive detect ions of taste and odour at

consumer taps.

In September, United Uti l i t ies recorded a petrol/solvent/f ishy taste and

odour in a sample taken from the Westhoughton zone, near Bolton. The

investigation carr ied out by the company found the same odour in samples

taken from neighbouring propert ies. Further analysis of samples found

naphthalene compounds that can give r ise to f ishy odours. A f it t ings

inspect ion carr ied out at the property identif ied a number of minor

infr ingements regarding backf low protect ion of k itchen appliances and

Northe rn reg ion

45

the heat ing system. Enhanced monitoring was carr ied out and no further

odours were detected.

In March, a sample taken at a consumer ’s tap by Yorkshire Water in the

Pateley Br idge/Ripon 2004 zone, (near Harrogate) was found to have a

solvent/petrol/ turpentine l ike odour. The company issued do not drink

advice to the consumers whi le investigating. Although no evidence of

a spi l lage of petrol was found, the service pipe was replaced and

subsequent tests were satisfactory. The ground contaminat ion is l ikely

to have occurred at some t ime in the past and taken t im e to migrate and

impact on water pipe.

Chemical

In May, Dee Val ley Water detected a chemical taste in a sample taken

from the City zone (Chester). A f it t ings inspect ion was carr ied out and it

was noted that there were no check valves f it ted to the kitchen appliances.

The consumer conf irmed they had noticed an intermittent taste and was

given advice about f it t ing check valves.

Drinking water quality events

Water quality events are classif ied into f ive broad categories based on the

init ial company report. The categories are:

Not significant: no further information required by an inspector to assess

the event.

Minor: i t is unl ikely that further information would be required by an

inspector to assess the event .

Significant: a ful l company report is usual ly required to enable an

inspector to assess the event .

Serious: in addit ion to a full company report, the assessment may involve

more than one inspector in the investigat ion.

Major: in addit ion to a full company report, wil l require an investigation led

by senior inspectors involving extensive information gathering and usual ly

site vis its.

In 2011, companies in the Northern region notif ied the Inspectorate of

70 events. Table 19 shows how these events were classif ied.


46

Table 19: Water quality events in the region in 2011

Nature of event Risk assessment category (DWI)

Minor/not-signif icant

Signif icant Major/serious

2010 2011 2010 2011 2010 2011

Air in water - 1 - 3 - -

Chemical 1 3 - 2 - -

Discoloured water 2 5 18 14 - -

Inadequate t reatment 6 1 9 13 - -

Loss of suppl ies/poor pressure 3 1 6 4 - -

Microbiological 4 - 3 6 - -

Taste/Odour 3 1 4 1 1 -

Health concern 1 - 6 3 - -

Publ ic concern 14 9 5 1 - -

Other 1 2 5 - - -

Region overal l 35 23 56 47 1 -

England and Wales 222 251 160 135 9 2

A summary of the nature, cause and durat ion of each event categorised

as signif icant, serious or major , along with details of the Inspectorate ’s

f indings are set out in Annex 3 . Most events were of relat ively short

durat ion and the company took appropriate act ion to inform and safeguard

consumers and other stakeholders. When compared to 2010, in the

Northern region in 2011 there were fewer signif icant, ser ious and major

events (47 compared to 57 in 2010) .

Wider learning points f rom event assessments in the region in 2011 are

highl ighted by the following cases :

Detection of E.coli in treated water reservoir

In June, E.col i was detected in a sample taken from Boughton works ,

in Chester, operated by Dee Valley Water. The works abstracts water f rom

the River Dee and treatment is by dissolved air f lotat ion (DAF) , rapid

gravity f i l t rat ion (RGF) and granular act ivated carbon (GAC). Treated

water then passes into a series of reservoirs and a water tower before

entering the distr ibut ion system. Al l investigational samp les were

satisfactory except for one taken from Boughton water tower. A similar

event had occurred in 2005 when Dee Valley Water failed to identify the

cause. A subsequent audit in 2006 by the Inspectorate raised concerns

about the water tower and a recommendation was made to review the

arrangements. In January, the company used a remotely operated vehicle

(ROV) to inspect the circular reservoir and the water tower as part of

ongoing company investigations of this works. This conf irmed its poor

condit ion. In the 2006 audit , the Inspectorate had noted the company’s

practice of dosing the tower with sodium hypochlorite and advised this

would negate the purpose of microbiological test ing at service reservoirs

( indicators of integrity). When assessing the 2011 e vent it was evident that

the company had continued with the pract ice ( ignor ing the advice given) to

Northe rn reg ion

47

the detr iment of water quality. Disappoint ingly , the company had failed to

take the tower out of service to enable repairs and also disregarded its

own procedures for managing water turnover in these structures.

Addit ional ly, alarms that respond to a deteriorat ion in treated water qual ity

were not acted on in a t imely manner. In l ight of all the information

available, including the company’s r isk assessment, the Inspectorate

concluded that the control measures were no longer suff icient and carr ied

out a further audit in October (see the Technical audit act ivity section )

whereupon further def iciencies were found at the works (f i l ter management

and the l ime plant). The tower taken out of supply and enforcement act ion

was taken. A Notice was put in place in March 2012 sett ing out short-,

medium-, and long-term measures with agreed t imescales to protect publ ic

health.

The Inspectorate is very cr it ical of the compan y for relying on a short -term

measure (manual dosing of chlorine) for years and not carrying out

medium-term measures ( inspect ion) and long -term measures (remediat ion

of integrity defects). This event i l lustrates why those companies who dose

chlorine into reservoirs to mask evidence of integrity problems are i l l

advised to do so. This event also highl ights the need for Directors to

always satisfy themselves personal ly that advice given by the Inspectorate

is not disregarded.

Loss of treatment and discolouration to supplies, Northumbria

In July 2010, a burst occurred on a 55 inch raw water main serving a

strategic works supplying over 500,000 consumers mainly in the Tyneside

area . Northumbrian Water’s prior ity in responding to the event was to

secure supplies by restart ing the works once a raw water supply was

available. A temporary repair to the 55 inch main was made, the

functionality of which proved problemat ic. Fol lowing this repair, consumers

began to report discoloured water, low pressure and no water.

In paral lel to repair ing the main, the company put in place plans to instal l

a bypass (over land temporary main and pump) to bring another nearby raw

water main into use. The Inspectorate was crit ical that the company

reinstated, albeit for emergency use, a previously abandoned source

without an adequate r isk assessment being made at the t ime of

reinstatement. The Inspectorate put in place a Notice requir ing the

company to make a r isk assessment for the raw water source. Contingency

plans for alternate supplies (tankers, stat ic tanks and bott led water) were

put in place together with other act ions to conserve and support supplies.

A more permanent repair was carr ied out by the end of July and this

reinstatement of the normal works conf igurat ion caused over 1,600

consumer contacts about discoloured water af terwards during August.

Companies are reminded that they are under a duty to have in place


48

up-to-date r isk assessments for all standby or new sources of raw water

and these r isk assessments must inform how suppl ies to customers are

maintained dur ing an event, both in the short and medium term.

Repeated loss of treatment causing elevated pH levels in supply

During 2011, United Uti l i t ies reported three water quality events at a water

treatment works in the Ennerdale area of Cumbria and a fourth event at

this s ite has been reported in 2012.

The works treats water f rom the River Ehen by membrane f i l t rat ion and

chlorination. Dur ing 2011, problems were experienced in relat ion to the

procedures for maintaining and cleaning the membranes. The works is

designed to automat ical ly shut down when a signal is received f rom a

treated water pH monitor indicat ing a value higher than the preset cr iter ia.

However, water with elevated pH was leaving the works and on

investigation this was found to be due to membrane cleaning chemicals

passing through a valve into a tank containing water used to backwash the

f i l ters. The company found that the valves were not operat ing as intended

because the seals had failed. The situat ion was e xacerbated by sett ings

in the sof tware controls, which allowed backwash wastewater to enter

mult iple f i l ter units. When these pH problems occurred dis infect ion was

compromised. Dur ing a site audit , in February 2012, the Inspectorate was

crit ical of the company for not act ing quickly to identify the problem with

a key component of the treatment process and modify the site

conf igurat ion in a t imely way. The backwash water system at a works is

intended to be a discrete process separate f rom the treated water process

stream, it was of concern therefore that the arrangements at this works

were not managed and control led in an appropr iate manner. The audit

highl ighted def iciencies in maintenance planning because it required

mult iple valve seal fai lures to prompt a replacement programme. In March

2012, United Ut il i t ies provided the Inspectorate with an updated r isk

assessment sett ing out control measures to mit igate against a recurrence

of this event – replacement of valve seals, solenoids and actuators,

improvements to the air compression system and installat ion of a chemical

neutralisat ion system in the backwash stream at the works. In Apri l, the

Inspectorate put in place a Not ice detail ing the short -, medium- and long-

term measures and agreed t imescales. Compani es are reminded that r isk

assessments should be updated immediately fol lowing each event.

The offence of supplying water unf it for human consumption is under

considerat ion by the Inspectorate in connection with one event in this

region.

Northe rn reg ion

49

Technical audit activity

The Inspectorate has operated a r isk -based approach to technical audit

since 2005 and no technical audit takes place without a reason.

On 14 December 2011, and in l ine with the Government ’s Better

Regulat ion policy, Parl iament gave the Chief Inspe ctor powers in the

Publ ic Bodies Bil l to recover the costs of its regulatory act ivit ies f rom the

industry f rom January 2013 onwards. Dur ing 2012, the Inspectorate has

consulted the industry and other stakeholders on the proposed charging

regime, the detail of which wi l l be set out in Orders laid under the Bi l l in

autumn 2012. Whereas the work of inspectors in assessing companies’

compliance with the drinking water monitoring requirements as set out in

the drinking water regulat ions can be predetermined, the technical audit

act ivit ies of inspectors is less predictable, however, the nature and volume

of technical audit act ivity over the past seven years is i l lustrated in Figure

20 as an indication of the scope and extent of the new charging

arrangements going forward.

Figure 20: Audit activity in the region 2005–2011

0

10

20

30

40

50

60

70

2005 2006 2007 2008 2009 2010 2011

Nu

mb

er

of

au

dit

s

Abstraction and treatment

Service reservoir integrity and management

Distribution operational maintenance

Sampling and analysis

Response to recommendations

Compliance with requirements for Legal Instruments

Other

Consumer complaint handling

Table 21 sets out all the r isk -based technical audits, which took place

in the Northern region during 2011 together with summary f indings. This is

followed by information about industry wide t hemes assessed during the

year and the part iculars of consumer complaint investigations by

inspectors, including a case study.


50

Table 21: Summary of the Inspectorate ’s technical audits f indings

in the Northern region in 2011

Company Location and reason

Main f indings from audit

Audit focus: Abstract ion and treatment

United Ut i l i t ies

Piethorne works – events

General ly sat isfac tory.

Noted lack of procedures around cr i ter ia for changing raw water sources and lack of v is ib i l i t y of ca l ibrat ion status for monit ors.


Riv ington works – events

Unsat isfac tory.

Crit ical that the coagulat ion fai lsafe commissioned in 2009 fa i led to work and th is was not examined dur ing event invest igat ion.

Noted poor control of l ime dos ing, incorrect ly labeled monitor (pH moni tor labeled turbid ity) , no guidance or procedures regarding change in coagulant dose, no records of f i l ter washing witness ing (spec if ica l ly which f i l ter) .

Concern expressed about the r isk ident i f ied when recyc led backwash water exceeds 10% dur ing works f low at t imes of low output.


Lostock works – turb idi ty fai lures


Noted issues wi th l ime dosing and pH contro l, a lso ir regular f i l ter washes and loss of f i l ter media.


L ingley Mere , a larm management centre – a larm handling issues


High volume of a larms being received, project underway to improve the system .

Dee Val ley Water

L lwyn Onn works – turb id i ty and pH

Unsat isfac tory.

A Not ice has been put in p lace in re lat ion to required improvements to mit igate the fol lowing ident i f ied r isks:

condit ion of l ime dos ing p lant ;

condit ion of f ina l water reservoirs ;

no treatment for manganese and insuf f ic ient treatment for Cryptospor id ium .

Dee Val ley Water

Boughton works – event and microbiol ig ical fai lures

Unsat isfac tory.

Noted poor dis tr ibut ion of air scour on granular act ivated carbon f i l ters.

Issues wi th the l ime plant, mature trees adjacent to treated water reservoirs and general lack of maintenance.

Enforcement act ion taken. Not ice issued in re lat ion to the tower that was in a s tate of d isrepair wi th holes in roof , roof covered in b ird guano and roof dra inage inadequate. Holes the s ize of p igeons in the internal tank.

Northe rn reg ion

51



Audit focus: service reservoir integrity and management


Dunham reservoir – m icrobiological fai lures

Unsat isfac tory.

Recommended secur ing seals around roof hatches, repair of the numerous cracks, review of the need for booster chlor inat ion, removal f rom s ite of out of date chemicals.

Company asked to invest igate the reason why in let water chlor ine levels were zero at reservoir on day of audit .


Knutsford reservoir – m icrobiological fai lures

Unsat isfac tory.

Noted issues about booster chlor inat ion on s ite .

Recommend the company review the pos it ion of the sampl ing tap to ensure i t is representat ive of water in the reservoir .

Audit focus: Distr ibution operat ional maintenance


Contractor – water supply hygiene

Sat isfac tory.

In ternal audi ts were being carr ied out .

Good staf f hygiene awareness .


Contractor – water supply hygiene

Sat isfac tory.


Good staf f hygiene awareness .


Meter f i t t ing – water supply hygiene

Sat isfac tory.


Lack of company process where lead p ipes are ident i f ied dur ing tapping work . Paper records ex is t , but no evidence of fo l low-up act ion.


Water supply hygiene tra in ing records,

Sat isfac tory.

In ternal audi ts were being carr ied out.


52



Dee Val ley Water

Meter f i t t ing and depot – water supply hygiene

Unsat isfac tory.

Fuel can in van secured, but not contained/bunded.

Supervisor had to prompt re -d is infect ion of pipe end af ter cut ends were ‘ f i led ’ wi th angle gr inder.

Ends d ipped in bucket of d ir ty chlorous , no d is infect ion of internal surfaces of new sect ion, due to l im its of d is infect ion method (see below) .

Method issues

Dis infect ion of ends/f i t t ings carr ied out wi th a paint brush f rom an open conta iner of ch lorous throughout the job such that chlorous becomes increas ingly d i r ty and therefore less ef fect ive.

Solut ion is made up week ly f rom 10% stock l iqu id solut ion, ( i .e . not tablets) – not best pract ice.

Weekly solut ion carr ied on van has no date of expiry, though of f ice paper records are kept .

Procedures prescr ibe the need for operators to car ry out water qual i t y hygiene checks for a l l network jobs, but th is is not documented and therefore the procedures are not amenable to audit .

No f lushing guidance other than to ‘ run unt i l c lear ’ . Need for a more measured approach.

Qual i t y of storage ar rangements incons istent (need a d isc ipl ined approach to mainta in ing a common s tandard) – p ipes a l l of f the ground, but many uncapped ends observed, method of capping var ied, some caps in poor state of repair ( fa l len apart, in some cases) or poor ly f i t ted. Some ends covered in b lack b in bags in very poor state of repair f rom wind damage, possib ly animal damage, some covered in robust p las t ic .

Some f i t t ings stored outs ide the secure compound – of f ground, some covered some not, some in tota l ly unsuitable condi t ions by per imeter fence against external vegetat ion.

No apparent procedure for control of reuse of o ld stock.

No vermin contro l – ment ion of occas ional mouse and rabbits on s it e .

Audit focus: consumer complaint handling


I l lness (1)

Taste and odour (2)

Sat isfac tory in each case.

Northe rn reg ion

53



Yorkshire Water

Other (1) Sat isfac tory.

Audit focus: Compliance with requirements for Legal Instruments

Dee Val ley Water

Wrexham r ing main – manganese undertak ing

Content of under tak ing negot iated and Legal Ins trument now in place.

During 2011, the Inspectorate audited the water supply hygiene

procedures of 11 companies across England and Wales following receipt

of information which increased the Inspectorate’s overall assessment of

r isk associated with the way companies carr ied out work in their

distr ibut ion systems. These audits covered equipment storage condit ions

in depots and vans, as wel l as mains repairs and meter insta l lat ions.

The outcome of a majority of the audits were general ly sat isfactory , but

examples of poor pract ice were identif ied where contaminat ion of drinking

water might have, or did, occur as a consequence of unsuitable storage of

f it t ings, pipes and other materials, insuf f icient clearance of soil f rom

around open pipes or connect ions, inadequate f lushing or dis infect ion and

a lack of good hygiene within vans. The f indings were summarised and

published in an Information Letter (IL 04/2012) to promote industry-wide

learning and improvement in this crit ical ly important aspect of day -to-day

operat ions.


54

Figure 22: An example of unsuitable storage of pipes prior

to installation

Complaints to the Inspectorate

The number of consumers who had cause to complain to the Inspectorate

because the company failed to resolve a water qual ity concern has fallen

in the Northern region f rom 11 in 2010 to four in 2011. Consumers also

contact water companies when they are dissat isf ied with their water qual ity

and complaints regarding appearance, taste and odour and incidence of

i l lness have decreased from almost 39,000 in 2010 to just over 35,000 in

2011. The region has seen a year -on-year reduction in contacts and levels

are now just above half of those reported in 2005.

Table 23 shows the number of complaints about water qual ity received by

the Inspectorate in 2011 alongside the annual rate of consumer contacts

to water companies about water qual ity issues. General ly , complaints

made direct ly to the Inspectorate arise when a company’s handl ing of a

consumer contact has fallen short of best pract ice and this only comes to

l ight as a result of intervention by an inspector. For this reason, there is

no direct relat ionship between the f igures set out in Table 23 and it is not

uncommon for complaints to the Inspectorate to be f rom customers of

companies exhibit ing a low rate of consumer contact generally. In the

Northe rn reg ion

55

Northern region in 2011 this can be seen to be the case in relat ion to the

f igures for United Ut i l i t ies and Yorkshire Water.

Table 23: Complaint rates to industry and to the Inspectorate

Company Rate of consumer contacts per 1,000 people

1 to water

companies in 2011

Number of complaints received by the

Inspectorate in 2011

Dee Val ley Water

4.8 -

Har t lepool W ater

4.4 -


2.6 -

Peel Water Networks

- -

Uni ted Ut i l i t ies 2.4 3

Yorkshire W ater 2.6 1

Industry rate 1.9 34

1Rate o f contac ts for appearance, tas te and odour and i l lness .

During 2011, the fol lowing complaint case i l lustrates why the Inspectorate

considers it important that companies have in place ef fect ive arrangements

for diagnosing consumer contacts.

Case example

In October, a consumer l iving in the Nantwich area of Cheshire contacted

the Inspectorate about a strong chlor ine tas te in tap water. This consumer

l ived in a supply zone affected during 2010 by a taste and odour incident

caused by treatment problems at Hur leston works in Cheshire. United

Uti l i t ies had sampled at the property in response to his complaint and the

local supply main had been f lushed. The results were sat isfactory with no

unusual taste or odour detected , but the consumer remained unhappy. He

reported the taste problem as ongoing and expressed dissatisfact ion with

the company’s handl ing of his concerns. The company vis ited the property

on a number of further occasions taking more samples, offering a water

f i t t ings’ inspect ion and providing a check valve to isolate any white goods

or outside tap. Consumer contact data for the zone did not point to a wider

problem (only one similar complaint recorded in 2011).

The Inspectorate noted that chlor ine levels in samples were moderately

high, but typical for the zone (mean free chlorine value in 2011 was

0.36mg/l with maximum value of 0.7mg/l, value recorded at the consumer ’s


56

tap was 0.43mg/l). Chlor ine complaints are of ten tr iggered by f luctuations

in the level of chlorine and these are of ten l inked either to pump operat ion

or to seasonal factors l ike water temperature or source changes. However ,

this case ref lected a dif ferent phenomenon whereby a past water quality

incident results in some individuals in the affected populat ion having a

heightened awareness and sensit ivity . The phenomenon is documented in

the scientif ic l i terature and it is known that individuals have continued to

boi l tap water for periods of well over 20 years af ter the end of a water

quality incident. Companies should recognise the phenomenon as part

of a process of post event learning. I t is recommended that dif ferent

procedures should put in place for handl ing consumer water qual ity

contacts f rom zones impacted by signif icant water quality incidents.

For example, there should be ‘f lags’ to alert cal l handlers about the past

incident advising them that it may not be appropr iate to fol low standard

or generic cal l handl ing protocol as a consequence. Companies are also

reminded to inform consumers whenever work to improve water quality at

a treatment works or in the distr ibut ion network is l ikely to lead to changes

in the level or type of residual ch lorine. In addit ion, it should be standard

pract ice to per iodically review target and actual levels of residual chlor ine

and take steps to ensure these are st i l l appropr iate and acceptable to

consumers.

For further information on the Water Supply (Water Qual ity) Regulat ions

2000, or the microbiological and chemical parameters covered by the

regulat ions please refer to the DWI website (www.dwi.gov.uk) .

I f you have a need for more specif ic information than that on our website,

please contact us on the DWI enquiry l ine: 0300 068 6400.

Northe rn reg ion

57

Annex 1 Further sources of information

The publ icat ion Drinking water 2011 comprises the regional reports for

England and a report covering Wales. There are f our regional reports for

England (Central and Eastern, London and South East, Northern, and

Western) and one for Wales ( in two languages). Each report presents

information f rom 2011 under the following headings:

Overview of drinking water qual ity in the region.

Water supply arrangements.

Drinking water qual ity test ing.

Drinking water qual ity results.

Technical audit act iv ity.

Drinking water qual ity events.

There are also separate reports covering private water supplies, one

cover ing England and one covering Wales.

The reports and other content are publ ished on the DWI website

(www.dwi.gov.uk).

Content of the CD

The CD suppl ied with the printed report holds all of the above content and

addit ional ly it contains:

Water company look-up tables

These summarise al l the results of water company monitor ing in 2011.

They provide information on:

what was tested;

how many tests were performed;

the range of the results of test ing; and

how many tests failed to meet the standards.

Significant drinking water quality events in England and

Wales 2011

To promote shared learning, the Inspectorate has compiled a l ist of al l

events that occurred in 2011 which i l lustrate the nature and cause of each

event, the main act ions by the company and f indings f rom the inspectors’

assessments. Relevant content f rom this overal l l ist is conta ined in an

annex to each regional report.


58

Annex 2 Glossary and description of standards

These def init ions wil l assist the understanding of the report where

technical terms have been used.

µg/l microgram per l i t re (one mil l ionth of a gram per l i t re) .

1,2-Dichloroethane is a solvent that may be found in groundwater in the v ic in ity of industr ia l s i tes . W here necessary i t can be removed by spec ia l water treatment . A European health-based standard of 3μg/ l appl ies.

Acrylamide European heal th-based s tandard. A monomer is not normal ly found in dr ink ing water. I t is produced in the manufacture of polyacrylamides occas ional ly used in water treatment . I ts presence in dr ink ing water is l im ited by control of the product spec if icat ion. Standard is 0.1µg/ l .

Aesthetic assoc iated wi th the senses of taste, smel l and s ight .

Aggressive

a term used to indicate that the water has a tendency to d issolve copper (and other metals) f rom the inner surface of a p ipe or water f i t t ing such as a tap.

Alkali

a solut ion conta in ing an excess of f ree hydroxyl ions, wi th a pH greater than seven.

Aluminium occurs natura l ly in some source waters . I t is removed f rom dr ink ing water by convent ional water t reatment (coagulat ion and f i l t ra t ion) . Aluminium sulphate and polyaluminium chlor ide may be used as water treatment chemicals at some water treatment works. A nat ional standard of 200μg/ l appl ies.

Ammonium salts are natura l ly present in trace amounts in most waters. Their presence might indicate contaminat ion of sanitary s ignif icance and they interfere wi th the operat ion of the dis infect ion process. An indicator parameter wi th a guide value of 0.5mg/ l.

Northe rn reg ion

59

Analytical qual ity control (AQC)

the method used to ensure that laboratory analys is methods are performing correct ly.

Antimony is rare ly found in dr ink ing water . Trace amounts can be der ived f rom brass tap f i t t ings and solders. A European heal th -based standard of 5μg/ l appl ies.

Aquifer water -conta ining underground s trata.

Arsenic occurs natura l ly in only a few sources of groundwater. Spec if ic water t reatment is required to remove i t . A European health -based s tandard of 10μg/l appl ies .

Authorised departure author isat ion for a water company to temporar i ly supply water exceeding a dr ink ing water standard, granted by the author i t ies only when there is no r isk to human health.

Benzene is present in petro l. I t is not found in dr ink ing water , but i t can migrate thr ough underground p last ic water p ipes i f petro l is spi l t in the v ic in ity. A European health-based standard of 1μg/ l appl ies . Some bott led waters and sof t dr inks which inc lude sodium benzoate as an ingredient have been reported as conta ining benzene.

Benzo(a)pyrene is one of several compounds known as polycyc l ic aromat ic hydrocarbons (PAHs) . Their source in dr ink ing water is as a resul t of deter iorat ion of coal tar , which many years ago was used to l ine water pipes. Due to extens ive water mains refurb ishment and renewal i t is now rare to detect th is substance in dr ink ing water. A European health-based standard of 0.01μg/ l appl ies.

Boron in surface water sources comes f rom industr ia l d ischarges or f rom detergents in treated sewage ef f luents . The very low concentrat ions found in some dr ink ing waters are not a concern to publ ic heal th. A European heal th -based standard of 1mg/ l appl ies .

Bromate can be formed dur ing d is infect ion of dr ink ing water through a react ion between natura l ly occurr ing bromide and strong ox idants (usual ly ozone). I t may be generated in the manufacture of sodium hypochlor i te d is infectant . Except ional ly, groundwater can be contaminated wi th bromate, re leased f rom industr ia l s i tes . A European health-based standard of 10μg/ l appl ies.


60

Bulk supply water suppl ied in bulk , usual ly in treated form, f rom one water company to another.

Cadmium is rare ly detected in dr ink ing water and trace amounts are usual ly due to d issolut ion of impur it ies f rom plumbing f i t t ings. A Europea n health-based s tandard of 5μg/ l appl ies .

Catchment

when used in connect ion wi th water , the catchment is the area dra ined by a r iver or water body.

Chloramination the process of generat ing a chloramine d is infectant res idual in water leaving a treatment works.

Chloramine a substance formed by a react ion between chlor ine and ammonia, used as a d is infectant in d istr ibut ion systems because of i ts long - las t ing propert ies compared to chlor ine.

Chloride is a component of common sal t . I t may occur in water natura l ly, but i t may also be present due to local use of de- ic ing salt or sal ine intrus ion. An indicator parameter with a guide value of 250mg/l .

Chlorine residual the small amount of ch lor ine or chloramines present in dr ink ing water to maintain i ts qual i t y as i t passes through the water company’s network of p ipes and household p lumbing.

Chromium is not present in dr ink ing water . A European health-based s tandard of 50μg/ l appl ies.

Clostridium perfringens is a spore-forming bacter ium that is present in the gut of warm-blooded animals . The spores can survive d is infect ion. The presence of spores in dr ink ing water indicates h is tor ic contaminat ion that requires invest igat ion. The standard is 0 per 100ml.

Coagulat ion a process employed dur ing dr ink ing water treatment to ass ist wi th the removal of par t icu late matter.

Coliform bacteria

are widely d istr ibuted in the environment of ten as a result of human or animal ac t ivi ty, but some grow on p lant mat ter . Their presence in a water supply indicates a need to invest igate the integr i ty of the water supply system. The s tandard is 0 per 100ml.

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Colony counts are general techniques for detect ing a wide range of bacter ia, the types and numbers being dependent on the condit ions of the test . These counts , i f done regular ly, can help to inform water management, but they have no direct heal th s ignif icance. The s tandard is ‘no abnormal change’.

Colour occurs natura l ly in upland water sources. I t is removed by convent ional water treatment. A nat ional standard of 20mg/ l on the Plat inum/Cobalt (Pt /Co) scale appl ies .

Communicat ion pipe the connect ion f rom the water main to the consumer’s property boundary.

Compliance assessment a compar ison made by the Inspectorate of data gathered by water companies against standards and other regulatory requirements .

Compound a compound cons ists of two or more e lements in chemical combinat ion.

Concessionary supplies histor ica l f ree suppl ies of water for a householder , es tabl ished when a company wanted to lay mains across land and the landowner might agree, subject to a permiss ion, to take a supply of water f rom the main.

Conduct ivity is a non-spec if ic measure of the amount of natura l d issolved inorganic substances in source waters . An indicator parameter wi th a guide value of 2,500µS/cm.

Contact tank a tank, normal ly s i tuated on a treatment works s ite, which forms par t of the d is infect ion process. A d is infectant chemical (normal ly chlor ine) is dosed into the water as i t f lows into the tank. The per iod of t ime that the water takes to f low through the tank a l lows suf f ic ient ‘contact ’ t ime for the chemical to k i l l , or deact ivate, any v iruses or pathogenic organisms that may be present in the water.

Contravent ion a breach of a regulatory requirement.

Copper in dr ink ing water comes mostly f rom copper p ipes and f i t t ings in households. In general, water sources are not aggress ive towards copper, but problems very occasional ly occur on new hous ing estates. These ‘b lue water ’ events can be avoided by good p lumbing pract ices. A European health-based standard of 2mg/l appl ies .


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Cryptosporidium is a paras ite that causes severe gastroenter i t is and can survive d is infect ion. In the UK, cont inuous monitor ing is under taken at works c lassif ied by the company as being at s ignif icant r isk .

Cyanide is not present in dr ink ing water . A European health-based s tandard of 50μg/ l appl ies.

Dead leg refers to a p iece of p ip ing which is stopped of f at one end, but is connected to the supply at the other end and can result in stagnant water in the p ipework.

Distribution systems a water company’s network of mains, p ipes, pumping stat ions and service reservoirs through which treated water is conveyed to consumers.

Drinking water standards the prescr ibed concentrat ions or values l is ted in regulat ions.

EC Drinking Water Direct ive Counci l Direct ive 98/83/EC December 1998 – set t ing out dr ink ing water standards to be appl ied in member states.

Enforcement act ion the means, as set out in the W ater Act 1989 and consol idated into the W ater Industry Act 1991, by which the Secretary of State requires a water company to comply w i th certa in regulatory requirements.

Enterococci see Escher ichia col i .

Environment Agency the Environment Agency is respons ib le for mainta in ing or improving the qual i t y of f resh, marine, surface and underground water in England and W ales.

Epichlorohydrin can be found in trace amounts in polyamine water t reatment chemicals. I ts presence in dr ink ing water is l im ited by contro l of the product spec if icat ion. A European heal th -based standard of 0.1μg/ l appl ies.

Epidemiology a process of s tudying the d istr ibut ion of cases of d isease wi thin a populat ion in re lat ion to exposure to poss ible sources of the infect ion, wi th a v iew to establ ish ing the actual source of the infect ion.

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Escherichia col i and Enterococci

are bacter ia present in the gut of warm -blooded animals. They should not be present in dr ink ing water and, i f present , immediate act ion is required to ident i fy and remove any source of faecal contaminat ion that is found. The standard is 0 per 100ml.

Event

water companies have to inform the Inspectorate about occas ions when water qual i t y or suf f ic iency is af fected or when publ ic conf idence in dr ink ing water qual i ty may be impacted. The Inspectorate refer to these ins tances as ‘Events ’ .

Filt ration the separat ion of suspended par t icu late matter f rom a f lu id.

Fluoride occurs natura l ly in many water sources, espec ial ly groundwater. I t cannot be removed by convent ional water treatment so h igh levels must be reduced by b lending wi th another low f luor ide water source. Some water companies are required by the local heal th author i ty to f luor idate water supplies as a protect ion against tooth decay. The dr ink ing water standard ensures levels are safe in e ither c ircumstance. Fluor idat ion of water is a Depar tment of Health pol icy. A European health-based s tandard of 1.5mg/ l appl ies.

Geosmin a substance produced by the growth of a lgae, normal ly in surface waters which g ives r ise to a character is t ic ‘ear thy’ or ‘musty’ taste or odour.

Granular activated carbon an adsorbent f i l t ra t ion media used to remove trace organic compounds f rom water .

Gross alpha/gross beta

radioact iv i ty in raw water can or ig inate f rom natura l substances or f rom a spec if ic point emission. W ater companies are required to screen for radionuc l ides that emit e ither a lpha or beta par t ic les . I f such screening exceeds guide values (gross a lpha 0.1Bq/ l , gross beta 1.0Bq/ l) then fu l ler analys is for spec if ic radionuc l ides is carr ied out to determine the or igin.

Groundwater water f rom aquifers or other underground sources.

Hydrogen Ion

(pH)

gives an indicat ion of the degree of ac id i ty of the water . A pH of 7 is neutra l; va lues below 7 are ac id ic and values above 7 are a lkal ine. A low pH water may result in p ipe corros ion. This is corrected by adding an alkal i dur ing water t reatment. A specif icat ion of between 6.5 and 9.5 appl ies.


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Improvement programmes water company improvement works, these are legal ly b inding on the company and each programme wi l l remedy an actual or pote nt ia l breach of a dr ink ing water s tandard wi th in a spec if ied t ime per iod.

Indicator organism an organism which indicates the presence of contaminat ion and hence the poss ib le presence of pathogens.

Indicator parameter something that is measured to check that control measures, such as water treatment , are work ing ef fect ive ly.

Information Letter formal guidance to water companies g iven by the Inspectorate and publ ished on the Inspectorate ’s webs ite at www.dwi.gov.uk

Inspectorate The Dr ink ing W ater Inspectorate.

Iron is present natura l ly in many water sources. I t is removed by water treatment. Some iron compounds are used as water treatment chemicals. However, the commonest source of iron in dr ink ing water is corros ion of iron water mains. A nat ional s tandard of 200μg/l appl ies .

Lead very occasional ly occurs natura l ly in raw waters, but the usual reason for i ts presence in dr ink ing water is p lumbing in o lder propert ies. I f the water supply has a tendency to d issolve lead then water companies treat the water to reduce consumer exposure. The permanent remedy is for householders to remove lead p ipes and f i t t ings. A European heal th -based standard of 25μg/ l appl ies, but 10μg/l wi l l apply f rom 25 December 2013 onwards.

m3/d cubic metre per day.

Manganese is present natura l ly in many sources and is usual ly removed dur ing treatment . A nat ional standard of 50μg/ l appl ies .

Mean zonal compliance percentage

a measure of compl iance wi th dr ink ing water standards introduced by the Inspectorate in 2004.

Mercury is not found in sources of dr ink ing water. A European health-based standard of 1μg/ l appl ies.

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Methyl- isoborneol (MIB) a natura l substance produced by the growth of a lgae, normal ly in surface waters which g ives r ise to a character is t ic ‘eart hy’ or ‘musty’ tas te or odour. I t is detected by the method for assessing tas te and odour .

mg/l mil l igram per l i t re (one thousandth of a gram per l i t re) .

Microbiological assoc iated wi th the study of microbes.

Ml/d megal i tre per day (one Ml/d is equivalent to 1,000 m

3/d , or to 220,000 gal lons/d) .

Nickel occurs natura l ly in some groundwater and where necessary spec ia l treatment can be insta l led to remove i t . Another source of nickel in dr ink ing water is the coat ings on modern taps and other p lumbing f i t t ings. A European health -based standard of 20μg/ l appl ies .

Nitrate occurs natura l ly in a l l source waters a l though h igher concentrat ions tend to occur where fert i l isers are used on the land. Nitrate can be removed by ion exchange water treatment or through b lending wi th other low ni trate sources. A European health-based standard of 50mg/ l appl ies .

Nitrite is somet imes produced as a by-product when chloramine is used as the essent ia l residual d is infectant in a publ ic water supply. Chloramine is the res idual d is infectant of choice in large d is tr ibut ions systems because i t is more stable and long- last ing. Carefu l operat ion of the d is infect ion process ensures levels of ni tr i te are kept below the standard. A European health -based s tandard of 0.5mg/l appl ies.

Notice

an ins truct ion served by the Secretary of State ( in the case of water suppl ies , the Chief Inspector of W ater) requir ing spec if ic act ions to be taken by the rec ip ient wi th in a spec if ied t imescale.

Odour can ar ise as a consequence of natura l processes in surface waters, par t icular ly between late spr ing and ear ly autumn. W ater treatment with act ivated carbon or ozone wi l l remove natura l substances caus ing taste. The s tandard relates to the evaluat ions of a panel of people assessing samples in the laboratory.

Ofwat the water industry’s economic regulator .


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Oocyst the res istant form in which Cryptospor id ium occurs in the environment, and which is capable of caus ing infect ion.

Organoleptic character is t ics of a substance as detected by ou r senses, for example taste, odour or colour.

Ozone process (ozonation) the appl icat ion of ozone gas in dr ink ing water t reatment.

Parameters the substances, organisms and propert ies l is ted in Schedule 2 and Regulat ion 3 of the regulat ions. Parameter def in it ions can be found in th is annex.

Pathogen an organism which can infect humans and cause d isease.

PCV see ‘Prescr ibed concentrat ion or value’ .

Periodic review the economic regulator ’s process of sett ing water pr ices.

Pest icides any fungic ide, herbic ide, insect ic ide or re lated product (excluding medic ines) used for the control of pests or d iseases.

Pest icides – organochlorine compounds (aldrin, dieldrin, heptachlor, heptachlor epoxide)

are no longer used in the UK because they are pers is tent in the environment. They are not found in dr ink ing water . A European chemical standard of 0.03μg/ l for each compound applies .

Pest icides – other than organochlorine compounds

is a d iverse and large group of organic compounds used as weed k i l lers, insect ic ides and fungic ides. Many water sources conta in traces of one or more pest ic ides as a resul t of both agr icu ltura l and non-agr icu l tura l uses, main ly on crops and for weed contro l on h ighways and in gardens. Where needed, water companies have insta l led water treatment (act ivated carbon and ozone) so that pest ic ides are not found in dr ink ing water . W ater companies must test for those pest ic ides used widely in their area of supply. Pest ic ide monitor ing thus var ies according to r isk . A European chemical standard of 0.1μg/l for each indiv idual substance and 0.5μg/ l for the tota l of a l l pest ic ides appl ies .

Phosphate dosing t reatment of water that resul ts in a protect ive f i lm bui ld ing up on the ins ide of p ipes minimising the l ike l ihood of lead being present in dr ink ing water suppl ied through lead p ipes.

Plumbosolvency the tendency for lead to d issolve in water.

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Polycyclic aromatic hydrocarbons

(PAHs)

is a group name for several substances present in petroleum-based products such as coal tar . (see Benzo(a)pyrene l is ted above for more informat ion) . A European health -based standard of 0.1μg/l for the sum of a l l the substances appl ies.

Powdered activated carbon (PAC)

powdered act ivated carbon is employed in treatment processes to remove pol lu tants.

Pre- and post-renovation assessment (PPRA)

a programme of assessment before and af ter mains renovat ion to demonstrate jus t i f icat ion for the work , and the improvements achieved by the renovat ion.

Prescribed concentration or value (PCV)

the numerical va lue assigned to dr ink ing water standards def in ing the maximal or min imal legal concentrat ion or value of a parameter .

Private supplies water suppl ied for human consumption or food product ion which is not provided by a water undertaker or l icensed water suppl ier .

Protozoan parasites a s ingle cel l organism that can only survive by infect ing a host .

Public Register dr ink ing water qual i t y informat ion made avai lable to the publ ic by water companies as required by regulat ions.

Public suppl ies water suppl ied by a company l icensed for that purpose.

Raw water water pr ior to receiv ing treatment for the purpose of dr ink ing.

Regulations The W ater Supply (W ater Qual i t y) Regulat ions 2000 (England), 2010 (W ales).

Remedial act ion act ion taken to improve a s i tuat ion.

Residual disinfectant the small amount of ch lor ine or chloramines present in dr ink ing water to maintain i ts qual i t y as i t passes through the water company’s network of p ipes and household p lumbing.

Risk assessment

a review under taken to ident i f y ac tual or potent ia l hazards to human heal th in a water treatment works and assoc iated supply system. Pr ior i t isat ion of r isk is based on cons iderat ion of l ikel ihood and consequence of the r isk occurr ing.

Secretary of State Secretary of State for Environment, Food and Rural Af fairs .


68

Selenium is an essent ia l e lement and a necessary d ietary component . Amounts in dr ink ing water are usual ly wel l below the standard. A European health-based s tandard of 10μg/ l appl ies.

Service connect ion connect ion between the water company's main to a consumer’s property.

Service pipe any p ipe subject to mains water pressure or subject to mains pressure but for the c los ing of some valve.

Service reservoir a water tower, tank or other reservoir used for the s torage of treated water wi th in the d istr ibut ion system.

Sodium is a component of common sal t . I t is present in seawater and brack ish groundwater . Some treatment chemicals contain sodium. Concentrat ions in dr ink ing water are extremely low, but some water sof teners can add signif icant amounts to dr ink ing water where they are ins ta l led in homes or factor ies. A nat ional standard of 200mg/ l appl ies.

Springs groundwater appear ing at the surface at the outcrop of the junct ion of a permeable stratum with an impermeable s tratum.

Sulphate occurs natura l ly in a l l waters and is dif f icu lt to remove by treatment. An indicator parameter with a guide value of 250mg/ l .

Supply pipe see service p ipe.

Supply point a point other than a consumer ’s tap author ised for the tak ing of samples for compl iance wi th the regulat ions.

Surface water untreated water f rom r ivers, impounding reservoirs or other sur face water source.

Taste can ar ise as a consequence of natura l processes in surface waters, par t icular ly between late spr ing and ear ly autumn. W ater treatment with act ivated carbon or ozone wi l l remove natura l substances caus ing taste. The s tandard relates to the evaluat ions of a panel of people assessing samples in the laboratory.

Technical audit the means of check ing that water companies are complying wi th their statutory obl igat ions.

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Tetrachloroethane and Trichloroethene

are solvents that may occur in groundwater in the v ic in ity of industr ia l s i tes . W here necessary they are removed by spec ia l is t t reatment. A European health-based standard of 10μg/ l for the sum of both substances applies .

Tetrachloromethane is a solvent that may occur in groundwater in the v ic in i ty of industr ia l s i tes. Where necessary i t is removed by specia l is t water t reatment. A nat ional standard of 3μg/ l appl ies .

Time of supply the moment when water passes f rom the water company’s pipework in to a consumer’s p ipework.

Total indicat ive dose is a measure of the ef fect ive dose of radiat ion the body wi l l receive f rom consumpt ion of the water . I t is calculated only when screening values for gross a lpha or gross beta (radiat ion) are exceeded. An indicator parameter wi th a guide value of 0.10mSv/year.

Total organic carbon represents the tota l amount of organic matter present in water . An indicator parameter wi th a guide value of ‘no abnormal change’ .

Toxicology the s tudy of the health ef fects of substances.

Treated water water t reated for use for domestic purposes as def ined in the regulat ions.

Trihalomethanes are formed dur ing d is infect ion of water by a react ion between chlor ine and natural ly occurr ing organic substances. Their product ion is minimised by good operat ional pract ice. A European health-based standard of 100μg/l appl ies .

Trit ium is a radioact ive isotope of hydrogen. Discharges to the environment are str ic t ly control led and there is a nat ional programme of monitor ing surface waters . An indicator parameter wi th a guide value of 100Bq/ l .

Turbidity is a measure of the c loudiness of water. At treatment works, measurement is an important non-specif ic water qual i t y contro l parameter because i t can be monitored cont inuous ly on l ine and a larms set to a lert operators to deter iorat ion in raw water qual i t y or the need to opt imise water t reatment. An indicator parameter wi th a guide value of 1NTU. When detected at the consumer’s tap i t can ar ise f rom disturbance of sediment wi th in water mains. A nat ional s tandard of 4NTU appl ies in th is case.


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Undertakings

legal ly b inding programmes of work agreed between a water company and the Chief Inspector of Dr ink ing Water to address actual or potent ial water qual i t y issues.

Vinyl chloride may be present in p las t ic pipes as a res idual of the manufactur ing process of polyviny l chlor ide (PVC) water p ipes. I ts presence in dr ink ing water is contro l led by product spec if icat ion. A European health-based standard of 0.5μg/ l appl ies .

Water supply zone a pre-def ined area of supply for establ ish ing sampl ing f requenc ies, compl iance wi th s tandards and informat ion to be made publ ic ly avai lable.

WHO World Health Organisat ion.

Wholesome/wholesomeness a legal concept of water qual i t y which is def ined by reference to s tandards and other requirements set out in the regulat ions.

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Annex 3 Not significant and minor drinking water quality events

Nature Number of not signif icant and minor events Area a ffected (est imate of populat ion affected)

Air in water (whi te ) 1 – NNE (1 ) Seaham, Durham (21,500)

Chemical 3 – UUT (3) Ecc les, Manchester (3) Blackburn, Lancashi re (3) Knuts ford, Cheshi re (3)

Discolourat ion 5 – DVW (1) , HPL (1) , NNE (1 ) , UUT (2) Washington, Tyne and Wear (20,908) Bury, Greate r Manchester (20,063) Skelmersdale, Lancashi re (13,458) Hart lepool (3 ,700) Farndon and Churton , Cheshi re (748)

Inadequate t rea tment 1 – NNE (1 ) Tees ide (585,853)

Loss of suppl ies / poor pressure

1 – NNE (1 ) Seaham and Dawdon, Durham (4,585)

Other 2 – HPL (1) , NNE (1 ) Procedura l issue wi th company sampl ingon two occas ions (No consumers were d i rec t ly a f fected)

Publ ic concern 9 – DVW (1) , UUT (5 ) , YKS (3 ) Oldham, Greate r Manchester (3) Farn ley, Leeds (43) Ki rk Bramwith, South Yorkshi re (50) Concess ionary supply (3 ) on three occas ions Mir f ie ld , W est Yorkshi re (50) Concess ionary supply (5 ) Chester (30)

Taste o r odour 1 – YKS (1) Pate ley Br idge, North Yorkshi re (5)

Total 23 – DVW (2) , HPL (2 ) , NNE (5) , UUT (10) , YKS (4)

671,019


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Significant, serious and major drinking water quality events

Date and durat ion

Area Estimate of populat ion affected

Nature and cause of the event

Main act ions and f indings from the Inspectorate investigat ion

01 Jan 2011 For 10 hours (UUT)

El lesmere por t , Su t ton Hal l and the W irra l

374,734 Turb id i ty due to depos i ts in contact tank.

United Uti l i t ies Water Plc act ion:

Review of procedures.

Sampled af fected a rea.

DWI comments and f indings:

Inadequate procedures.

High turb id i ty in f ina l wa ter caused by a d is tu rbance of depos i ts wi th in the contact tank fo l lowing changes in f low through the works.

Risk c lass i f icat ion: Sign i f icant .

02 Jan 2011 For 5 days (NNE)

Stockton, Tees ide

82,638 Brown d isco lourat ion. Northumbrian Water Ltd act ion:

F lushed mains.

Sampled a f fected a rea.

Rezoned area (brought in water f rom d i f fe rent source) . DWI comments and f indings:

Th is event was caused by changes in demand in the network due to leakage caused by ext reme cold weather .

No recommendat ions or suggest ions made. Risk c lass i f i cat ion: Sign i f icant .

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Date and durat ion




03 Jan 2011 For 5 days (YKS)

Sk ipton, Grass ington, North Yorkshi re

58,000 Treatment fa i lu re. Yorkshire Water Services Ltd act ion:



Closed the Nidd supply d i rect to the wor ks, un t i l the in le t f low meter could be rep laced.

In the longer term, addi t ional t reatment s tages and fa i lsafe ch lor inat ion is to be ins ta l led.


Under dos ing o f fer r ic coagulant dos ing due to h igh in le t f lows caused by fa i lure o f in le t va lve.

Cr i t ica l that equipment was not ident i f i ed .

Recommended inspect ion of wind ings and assessment of the i r condi t ion as par t o f the commiss ion ing process for any fu ture changes to contro l arrangements at a l l the company’s s i tes .

Risk c lass i f ica t ion: Sign i f icant .

06 Feb 2011 For 2 days (NNE)

28 propert ies near Holy Is land, Northumber -land

70 Microbio log ica l contaminat ion.

Northumbrian Water Ltd act ion:



Bypassed service reservo i r .

Laboratory audi t .

Remedia l work to service reservo i r . DWI comments and f indings:

E.col i detected in a rout ine water sample fo l lowing heavy ra in fa l l . The reservo i r was taken ou t o f supply and a subsequent inspect ion ident i f ied points of ingress, the s i te was repai red and re tu rned to supply.

The Inspectorate sugges ted that the company pointed out that the regulato ry r i sk assessment should be updated to re f lec t the event and act ions.



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Date and durat ion




07 Feb 2011 For 4 hours (UUT)

Tameside, Greate r Manchester

177,370 Treatment fa i lu re and e levated turb id i ty .



Ins ta l led new coagula t ion pH moni tors (more re l iab le model ) .

Developed a check l is t to be completed dur ing va lve maintenance to ensure s tatus is correct and known.

Refresher t ra in ing for operat ives on coagulat ion best pract ise.


Inadequate t rea tment process – c lar i f icat ion.

Inadequate number o f samples taken.

Cr i t ica l o f the length o f t ime taken to ga in contro l o f the t reatment process and conc luded th is impacted adverse ly on d is in fect ion process.

Recommended update of procedures to ensure act ion is taken to restore wate r qual i ty to normal in a t imely manner.

Conc luded that the root cause of the deter iorat ion in raw water qual i ty that t r iggered th is even t was l inked to a mal funct ion of the wastewater p lan t , which was exacerbated by a c losed actuated va lve.

Recommended review o f maintenance procedures to ensure that va lves are not le f t in the wrong pos i t ion and s tatus is ver i f ied as par t o f the procedure for re turn to normal operat ion fo l lowing maintenance or commiss ion ing.


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Date and durat ion




07 Feb 2011 For 3 days (UUT)

Southport , Sef ton, Merseys ide

143,169 Fai lure of the d is in fect ion system due to p lant fa i lu re.



Shut down t reatment works.

Repai red fau l ty equipment .


Inadequate t rea tment process – d is in fect ion.

Inadequate invest igat ions in to root cause.

The company fa i led to ident i fy that a fa i lsafe sys tem was not work ing as des igned. The company were not ab le to a l ter sof tware which provided the arch ive for s i te readings and records due to system no t be ing compat ib le wi th exis t ing equipment .

The Inspectorate was cr i t ica l that the company has inadequate cont ingency p lans.

The Inspectorate was cr i t ica l o f maintenance and p lanning re la t ing to th is event and a lso the suf f ic iency of the company reports .


14 Mar 2011 For 2 weeks (UUT)

Manchester 250,000 Musty taste o r odour . United Uti l i t ies Water Plc act ion:


Shut down Denton works.

Retra ined s ta f f .


Ins ta l led granular act iva ted carbon t reatment subsequent ly.



Inaccurate customer con tact data.

Inadequate raw water moni tor ing s t ra tegy to detect emerg ing issues.

The Inspectorate recommended that the learn ing points and f ind ings be suppl ied fo l lowing th is even t and suggested revis ion of procedure s, and suggested that an undertak ing be cons idered at th is works to address methyl - isoborneol (MIB) and geosmin ident i f ied r i sks.



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Date and durat ion




23 Mar 2011 For 3 days (UUT)

Anf ie ld , L iverpool

75,384 Discolourat ion due to a burs t main.



Repai red main.

F lushed mains. DWI comments and f indings:

Th is event invo lved the burs t o f two water mains and subsequent d isco lourat ion of suppl ies .

No recommendat ions or suggest ions were made. Risk c lass i f icat ion: Sign i f icant .

26 Apr 2011 For 1 day (UUT)

Bol ton, Lancashi re

85,766 Discolourat ion. United Uti l i t ies Water Plc act ion:

Rezoned area (brought in water f rom d i f fe rent source) .


Repai red fau l ty equipment . DWI comments and f indings:

Disco lourat ion caused by mains fa i lu re.

No recommendat ions or suggest ions made. Risk c lass i f icat ion: Sign i f icant .

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Date and durat ion




27 Apr 2011 For 5 days (NNE)

Shi remoor, Newcast le , Northumbr ia

25,200 Ai r in water (whi te ) due to p lanned work.




Company in tends to check and record the s ta tus of a i r va lves before they are recharged and recommiss ioned.


Inadequate r isk assessment .


Cr i t ica l that the t iming o f the va lve operat ions fo r both the recommiss ion ing and decommiss ion ing s tages were not updated on the appropr ia te documents and therefore the r isk assessment was not correct .

Very cr i t ica l o f poor communicat ions a nd documentat ion as th is is a repet i t i ve cause of even ts assoc iated wi th the company’s d is t r ibut ion network operat ions.

Enforcement act ion to be cons idered i f there are any fur ther s imi lar occurrences.



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Date and durat ion




27 Apr 2011 For 24 hours (UUT)

El lesmere por t , Su t ton Hal l and the W irra l

374,734 Cryptospor id ium . United Uti l i t ies Water Plc act ion:



Replaced fau l ty equipment .

Developed a s i te -spec i f i c cause and ef fect char t for coagulat ion at Sut ton Ha l l works to a id the opera t ion of the t reatment process.

Operato rs at Su t ton Hal l W orks are to be t ra ined in the opt imisat ion of coagulan t dos ing dur ing 2011.

Reviewed the coagulant dos ing a lgor i thm at th is works .

Submi t ted a revised W irra l Demand Moni tor ing Zone Regulat ion 28 report to the Inspectorate.

Regulat ion 26 improvement work to improve the contro l o f ferr ic a lumin ium sulphate dos ing to a ta rget f low set po int a t Sut ton Hal l works completed in June 2011.



The Inspectorate is c losely moni tor ing the company 's progress wi th act ions se t out in regulatory r isk assessment to improve the coagulat ion s tage at th is works and mi t igate ident i f ied r isks to water qual i ty.


Northe rn reg ion

79

Date and durat ion




12 May 2011 For 12 hours (NNE)

Conset t , Stanley, Chopwel l , Chester - le -Street and Lanchester , County Durham

184,000 Loss of ferr ic coagulant dos ing due to p lant fa i lure.





Due to la rge quant i t y o f s tored wate r , c lar i f ie rs and f i l ters were run to waste to recover the process before turb id i t ies exceeded 1NTU.

Developed in ter im s i te -spec i f ic p rocedures . DWI comments and f indings:


Inadequate communicat ions caused delay in response.

The even t was caused by sequent ia l fa i lure o f coagulant dos ing l ines.

The s ta f f were not adequate ly t ra ined to carry ou t manual coagulant dos ing.

Recommended update of regulatory r isk assessment and Cryptospor id ium moni to r ing, s ta f f t ra in ing and

development o f procedures. Risk c lass i f icat ion: Sign i f icant .

31 May 2011 For 24 hours (UUT)

Haydock, Merseys ide

3,793 Discolourat ion. United Uti l i t ies Water Plc act ion:

F lushed mains.

Sampled af fected a rea. DWI comments and f indings:

Probable i l legal use of hydrant by th i rd par ty.



80

Date and durat ion




01 Jun 2011 For 50 hours (UUT)

Preston, Lancashi re

5,718 Ai r in water (whi te ) due to p lanned work .



F lushed mains.

L ia ised wi th loca l media about d isco lourat ion as a resul t o f a p lanned a i r scour of the mains.

Aerat ion of suppl ies .


No recommendat ions or suggest ions made.


09 Jun 2011 For 3 days (UUT)

Tonge Moor Bol ton, Lancashi re

12,505 Discolourat ion due to th i rd par ty damage .

United Uti l i t ies Wate r Plc act ion:


Repai red main.


Inadequate invest igat ions in to root cause.


Cr i t ica l that the company d id no t use a l l too ls avai lab le to ident i f y root cause.

Recommended review o f procedures to ver i f y the qual i ty o f water be ing suppl ied to consumers dur ing events .


17 Jun 2011 For 24 hours (YKS)

Colburn, W est o f Cat te r ick , North Yorkshi re

3,392 Microbio log ica l contaminat ion.

Yorkshire Water Services Ltd act ion:


Increased ch lor ine res iduals at service reservo i r .

Carr ied out an in te rnal and exte rnal inspect ion of both compartments and ident i f ied points of ing ress.

Repai red defects .


Th is event was caused by dete r iorat ion in the condi t ion of the asset .



Northe rn reg ion

81

Date and durat ion





Concess ionary supply, Stockport , Manchester

3 Issue of a do not dr ink not ice.


Issued a do not dr ink no t ice.

Provided bot t led wate r on request .


Addi t ional t reatment by March 2012.

Moni tor ing for parameters of in terest a t th is s i te (d ie ldr in and hydrocarbons) .


Th is event a f fected a concess ionary supply and was caused by migrat ion of contaminants in the ground through the p ipework.

The Inspectorate is moni tor ing the company 's progress towards f ind ing a permanent so lut ion to i ts concess ionary suppl ies in th is area wi th unsat is fa ctory water qual i ty .


23 Jun 2011 For 3 weeks (UUT)

Manchester c i ty centre

71,918 Discolourat ion due to re instatement o f burs t main.



F lushed mains.

Repai red main.


Inadequate br ie f ing of s ta f f and fa i lure to in fo rm consumers in advance o f work tha t might g ive r i se to d isco lourat ion.

See comments for event in Neston on the W irra l on 28 June 2011.



82

Date and durat ion




28 Jun 2011 For 49 hours (UUT)

Neston on the W irra l

17,050 Discolourat ion due to p lanned work.


Sampled af fected a rea .

Ins ta l led a va lve and recharged main.



Did not in fo rm customers.

Assessed in l ight o f o ther previous s imi lar d isco lourat ion events due to p lanned work in 2011 (23 June 2011 in Manchester and 28 June 2011 in the Crewe area) .

Recommended company reminds s taf f o f the need to carry out a fu l l assessment o f potent ia l impact on water qual i ty p r ior to work be ing carr ied out and to put in p lace appropr ia te mi t iga t ion measures.

Cr i t ica l that consumers in Neston, Cheshi re, d id not receive copies o f the le t ter because of e rror in r i sk assessment .

Recommended that the company use the in format ion gained f rom th is event to update Dis t r ibut ion Operat ion and Maintenance St rategy (DOMS) categor isat ion of r isk for th is area .

Cr i t ica l o f lack o f communicat ion between two a reas of the wate r company as root cause of fa i lu re to address consumer concerns.

Suggested regula tory r isk assessment is updated. Risk c lass i f icat ion: Sign i f icant .

Northe rn reg ion

83

Date and durat ion





Crewe, South Cheshi re

30,000 Discolourat ion . United Uti l i t ies Water Plc act ion:



The company p laced a message on i ts automat ic messaging system to in form consumers of the s i tuat ion, which was reviewed and updated regula r ly .

The company p lans to in t roduce a ref resher t ra in ing on best pract ice f rom June 2012 and assess the competency of i ts network operat i ves .


Cause due to p lanned work.


Inadequate t ra in ing/competence of s ta f f .

See comments for event in Neston, Cheshi re on 28 June 2011.

Risk c lass i f icat ion : Sign i f icant .

30 Jun 2011 For 1 week (UUT)

Areas to the nor th of Bol ton, Greate r Manchester suppl ied by Wayoh works

112,147 Chemical contaminat ion (pest ic ides) .





Dosed powdered act i vated carbon (PAC). DWI comments and f indings:


Th is event re la ted to the f ind ing of MCPA pest ic ide in a rout ine sample .



84

Date and durat ion




01 Ju l 2011 For 3 days (DVW )

Chester and North East Wales


Dee Val ley Water Plc act ion:


Inspected reservo i r .

Increased ch lor ine res iduals leaving the works . DWI comments and f indings:

Dur ing a pos t event audi t the Inspectora te found s ign i f icant def ic ienc ies wi th s torage of water in the tower.

The company had fa i led to act on the Inspectorate ’s recommendat ions f rom a previous audi t and even t assessment .

Not ice in p lace and the company are current l y work ing wi th the Inspectorate to agree the cont ro l measures and act ions to mi t igate a recurrence.


05 Ju l 2011 For 3 hours (UUT)

Areas nor th of Skelmersdale, Lancashi re

87,000 Treatment fa i lu re. United Uti l i t ies Water Plc act ion:



Improvements made to v is ib i l i ty o f t reatment s tages and opt imisat ion of process.


Th is event re la ted to a fa i lure in the coagula t ion s tage of t reatment .

Recommended s imulate cr i t ica l a larm set t ings to ensure they a re f i t for purpose in l ight o f event .

Recommended rout ine test ing and ver i f icat ion o f correct operat ion of the coagula t ion fa i lsafe shutdown.


Northe rn reg ion

85

Date and durat ion




18 Ju l 2011 For 4 days (UUT)

Huyton and centra l areas of L ive rpool

203,000 Burst on a s t ra teg ic 40” main .


Repai red main.


Inspected 40" t runk main and the mechanica l bond f i t t ings that had been used fo l lowing the cement l in in g of th is main in the 1990 's .


Cr i t ica l that i t was unc lear in company repor t how the f lows and pressures on the main were current l y mainta ined or how they would be mainta ined in the fu ture.

Recommended the company should ensure that cont ingency p lans a re in p lace for the operat ion and management of th is s t ra teg ic main dur ing normal and abnormal condi t ions.

Suggested learn ing f rom th is even t , about the spec i f ic make of mechanica l bond coupl ing in terms of the i r maintenance and the need for rep lacement on other , s t ra teg ic wate r mains.

Noted how the burs t on th is s t ra teg ic main caused widespread f looding and deal ing wi th th is overshadowed a l l cons iderat ions of water qual i t y by those responding to the event .


20 Ju l 2011 For 24 hours (UUT)

Areas nor th of Manchester suppl ied by Lostock works

782,658 Cryptospor id ium . United Uti l i t ies Water Plc act ion:


Repai red fau l ty equipment . DWI comments and f indings:

Th is event was caused b y temporary fa i lure of chemical dos ing at the works lead ing to loss of f i l te r per fo rmance.



86

Date and durat ion




08 Aug 2011 For 2 days (NNE)

Blaydon and W in laton, Gateshead, Tyne and Wear

80,922 Disco lourat ion due to p lanned work.




Provided an a l te rnat i ve supply by tanker/bowser .


F lushed mains. DWI comments and f indings:

Th is event was caused by inappropr ia te operat ion of a va lve caus ing scour ing o f the main.


21 Aug 2011 For 4 hours (NNE)

Wal ls end and Byker , Northumber -land



Repai red main.



The company mainta ined suppl ies , but caused d isco loured water by the ear ly act ions taken in deal ing wi th th is leak tha t threa tened loss of supply to a large populat ion.


Recommended that appropr ia te r isk assessments are a lways carr ied out pr ior to act ions being taken on the d is t r ibut ion network.

Risk c lass i f icat ion: Sign i f ican t .

Northe rn reg ion

87

Date and durat ion




02 Sep 2011 For 24 hours (UUT)

Stockport Greate r Manchester and surrounding areas suppl ied by W ybers ley works


Revised procedures.


Replaced fau l ty f low swi tches and made a l terat ions to sof tware and process contro l .


Th is event was caused by a fa i lu re of ferr ic dos ing at the works.

Suggested that main tenance act iv i t ies fo r f low swi tches be recorded and that cons iderat ion is made to the conf igurat ion of c r i t ica l dos ing equipment a t o ther s i tes wi th a review of a rrangements to ensure that these are access ib le for the purposes of maintenance.


06 Sep 2011 For 1 day (UUT)

Hasl ingden, Lancashi re and surrounding areas suppl ied by Grane works

60,954 Treatment fa i lu re . United Uti l i t ies Water Plc act ion:

Revised procedures.



Reviewed f i l ter management . DWI comments and f indings:

Th is event was caused by subopt imal coagulat ion

Suggest ions made on the manner in which backwash water is ob ta ined and managed.

Inspectorate was cr i t ica l o f cont ingency p lanning and acknowledged company act ions to add res i l ience .

The company has taken learn ing points fo r th is event and reviewed the conf igurat ion of o ther s i tes .



88

Date and durat ion




19 Sep 2011 For 33 hours (UUT)

Hyde, Centra l Manchester





Repai red main. DWI comments and f indings:


20 Sep 2011 For 24 hours (YKS)

Summerbr idge and Dar ley, North Harrogate, North Yorkshi re



Increased ch lor ine res iduals at service reservo i r .

Removed service reservo i r f rom supply.


Repai red cable access and roof jo in t . DWI comments and f indings:


24 Sep 2011 For 4 days (UUT)

Heswal l the W irra l , Merseys ide

8,840 Loss of suppl ies . United Uti l i t ies Water Plc act ion:



Main ta ined suppl ies by tanker ing in water to consumers. DWI comments and f indings:

Th is event was caused by a te lemetry fau l t caus ing booster pump at Heswal l service reservo i r to t r ip out .

Inadequate cont ingency p lanning. Risk c lass i f icat ion: Sign i f icant .

Northe rn reg ion

89

Date and durat ion




27 Sep 2011 For 6 days (UUT)

Accr ington, Lancashi re

17,250 Loss of suppl ies due to burs t main .




The company car r ied out a post learn ing review and undertook analys is o f the 800mm glass re in forced p last ic (GRP) main.



28 Sep 2011 For 3 days (YKS)

Dinnington Anston area o f Rotherham, South Yorkshi re

30,000 Discolourat ion. Yorkshire Water Services Ltd act ion:


Restored pumping and p rocesses at Aughton pumping s tat ion .


Th is event was caused by a fa i lu re of pumps at Aughton pumping s tat ion due to temporary power fa i lure .


05 Oct 2011 For 24 hours (UUT)

Hindley and surrounding areas, Lancashi re




Removed serv ice reservo i r f rom supply.

In ternal l y inspected the service reservo i r and ident i f ied two points of ingress.


Reservoi r wi l l remain ou t o f supply unt i l repai rs have been made.

Current l y no p lans to re turn asset to supply. Risk c lass i f icat ion: Sign i f icant .


90

Date and durat ion




06 Oct 2011 For 24 hours (UUT)

Whi tehaven and surrounding areas in Cumbr ia suppl ied by Ennerdale works



Restored t reatment p rocesses . DWI comments and f indings:

Th is event was caused by a va lve fa i lu re on a membrane f i l t ra t ion uni t which caused water wi th e leva ted pH to enter supply .

The Inspectorate audi ted th is s i te in Feb 2012.

Invest igat ion ongoing. Risk c lass i f icat ion: Sign i f icant .

11 Oct 2011 For 2 days (YKS)

Bradford , Leeds Yorkshi re



Repai red main.



14 Oct 2011 For 1 week (UUT)

Concess ionary supply in Chor ley, Lancashi re

3 Chemical contaminat ion.



Issued a do not use not i ce . DWI comments and f indings:

Th is event re la tes to the nature of the water be ing aggress ive towards copper p lumbing .

Not ice has been updated to take in to account the ongoing work that Uni ted Ut i l i t ies is do ing to br ing these suppl ies onto mains supply and a lso to protect publ ic heal th when fa i lures do occur.


Northe rn reg ion

91

Date and durat ion




15 Oct 2011 For 4 days (UUT)

Levenshulme, South Centra l Manchester




F lushed af fected area.

Repai red main.




19 Oct 2011 For 24 hours (YKS)

Harrogate area, North Yorkshi re




Replaced sampl ing fac i l i t ies at Har low Hi l l works .

Repai rs a t Eagle Hi l l and Har low Hi l l se rvice reservo i rs and an a i r va lve.


The cause o f E.col i fa i lu res were not ver i f ied , bu t a number of defects found dur ing the i nvest iga t ion have been addressed.

Suggested that in format ion f rom the most recent in ternal inspect ion and th is even t in forms the company’s approach to reservo i r inspect ions to ensure inspect ion f requenc ies are appropr ia te.

Suggested updat ing the re levan t r egulato ry r isk assessments .


01 Nov 2011 For 3 days (UUT)

Oldham, Greate r Manchester

15,015 Ai r in water (whi te ) due to p lanned work .


Sampled af fected a rea .

F lushed mains.

Reviewed procedures .


No recommendat ions or suggest ions were made. Risk c lass i f icat ion: Sign i f icant .


92

Date and durat ion






80,000 Treatment fa i lu re. United Ut i l i t ies Water Plc act ion:


Restored t reatment . DWI comments and f indings:

Th is event re la tes to h igh pH and low ch lor ine caused by issues wi th va lv ing arrangements and conf igurat ion at s i te .




80,000 Treatment fa i lu re . United Uti l i t ies Water Plc act ion:


Restored t reatment .

Reviewed t reatment p rocess and a larm set t ings. DWI comments and f indings:

Th is event was caused by the fa i lure of the membrane f i l ter un i t .


08 Dec 2011 For 36 hours (UUT)

Hind ley, Greate r Manchester

8 ,485 Discolourat ion due to a burs t main.


Repai red main.




Northe rn reg ion

93

Date and durat ion




11 Dec 2011 For 12 hours (NNE)

Washington, Jarrow and South Shie lds

557,730 Treatment fa i lu re . Northumbrian Water Ltd act ion:


Restored water t reatment processes.



Th is event was caused by a b lockage in the coagulant a id dos ing arrangements .

Recommended that where s tarch is used as a coagulant a id that the dos ing system used should be re l iab le and robust , and tha t th is should be the case at a l l company s i tes .


13 Dec 2011 For 6 hours (NNE)

Durham , Middlesbro ’ , Stockton, Hart lepool , Hambleton, Richmond, Dar l ington, Redcar and Cleveland, Northumber -land

544,700 Treatment fa i lu re . Northumbrian Water Ltd act ion:


Restored water t reatment processes.



Th is event was caused by problems wi th Starch dos ing for coagulat ion at th is works which d isrupted t reatment processes leading to e levated turb id i ty and d isco loured water .

The Inspectorate recommended that changes be made to the s tarch dos ing fac i l i t y a t th is works to ensure that i t can be cont inuous ly operated and is re l iab le .


15 Dec 2011 For 48 hours (YKS)

Scarborough and surrounding areas suppl ied by I r ton works

30,000 Cryptospor id ium . Yorkshire Water Serv ices Ltd act ion:


Increased ch lor ine res iduals at t reatment works and opt imised t reatment p rocesses.

Treatment ad justed to take account o f change in raw water qual i ty .






94

Events in the Northern region outstanding from 2010 completed in 2011

Date and durat ion



Main act ions and f indings from the Inspec torate investigat ion

15 Ju l 2010 For 5 days (NNE)

Hors ley works supplying Ashington, Lynemouth, El l ington, Blyth , Craml ington, Gosfor th , Longbenton and Whi t ley Bay

500,000 Burst raw water main. Northumbrian Water Ltd act ion:

Rezoned area and f lushed mains.


Deployed tankers and a l ternat i ve suppl ies .

Repai red main.


Breaches of Regulat ion 4 and fa i lure to complete Regulat ion 15 r isk assessment pr ior to us ing obsolete source water .

Not ice issued.

Prosecut ion in i t ia ted (see the Drink ing wate r qua l i ty events sect ion) .


22 Dec 2010 For 8 hours (UUT)

Oldham, Lancashi re and surrounding area

98,000 Dis in fect ion fa i lure. United Uti l i t ies Water Plc act ion:

Reduced works output .

Cleaned the su lphur ic ac id dos ing l ines.

Not i f ied Heal th Protect ion Uni t and Envi ronmenta l Heal th .

Replaced fau l ty equipment .


Inadequate t rea tment process – dos ing.

Recommended company update scheduled maintenance task l is ts for dos ing.

Recommended in t roduct ion of contro ls to mi t igate dos ing contro l r isks .

Recommended pr ior i t isa t ion of upgrades p lanned for th is works.


Note: A complete table of events in England and W ales in 2011 can be found on the CD in the fo lder. I t is named Signif icant drinking water events in England and Wales 2011.pdf . I t is also avai lable on the DW I webs i te (www.dwi.gov.uk ).

Northe rn reg ion

95

Annex 4 Planned drinking water quality improvements

Company Parameter , hazard or dr iver

Site Due for complet ion*

Status* Legal Instrument

DVW E. Col i Boughton 31-Mar-14 Ongoing Not ice

DVW Ingress L lwyn Onn 31-Sep-11 Completed

04-Aug-11 Not ice

DVW Manganese, Cryptospor id ium

L lwyn Onn 30-Jun-13 Ongoing Not ice

NNE I ron Dis t r ibut ion system – Tynes ide

30-Mar-15 Ongoing Not ice

NNE I ron Dis t r ibut ion system – W ears ide


NNE I ron and Manganese

Consumer acceptabi l i ty measures – d is t r ibut ion system

30-Mar-11 Completed

31-Mar-11 Undertak ing


Dis t r ibut ion system –Teesdale and Teess ide

30-Apr-13 Ongoing Undertak ing


Dis t r ibut ion system – Tynes ide

31-Mar-15 Ongoing Undertak ing

NNE Lead Dis t r ibut ion system 31-Mar-15 Ongoing Undertak ing

NNE Meta ldehyde Hors ley catchment 31-Mar-15 Ongoing Undertak ing

NNE Meta ldehyde Lumley catchment 31-Mar-15 Ongoing Undertak ing

NNE Meta ldehyde Warkworth catchment


NNE Meta ldehyde Whi t t le Dene catchment


NNE Pathogens Northern t runk main system

30-Nov-12 Ongoing Undertak ing

UUT Colour and Tota l Tr iha lomethanes

Clay Lane 31-Dec-13 Ongoing Undertak ing


Kinder/W ybers ley catchment



Lake Vyrnwy catchment

31-Ju l -14 Ongoing Undertak ing


Woodhead/Arnf ie ld catchment


UUT Cryptospor id ium Concess ionary supply (1 )









31-Mar-12 Delayed Not ice








96





31-Mar-11 Completed 31-Mar-11

Not ice

UUT Cryptospor id ium Concess ionary supply (10)


UUT Integr i t y and raw water p rotect ion

Grange 31-May-12 Completed

28-Feb-12 Not ice

UUT I ron Vyrnwy – t runk main 31-Dec-20 Ongoing Undertak ing

UUT I ron and Manganese

Bi rkenhead – t runk and d is t r ibut ion mains

31-Aug-16 Ongoing Undertak ing


Blackpool and Lytham – t runk and d is t r ibut ion mains



Car l is le – t runk and d is t r ibut ion mains

30-Apr-20 Ongoing Undertak ing


Cleveleys Thornton – t runk and d is t r ibut ion mains

31-Ju l -12 Ongoing Undertak ing


Crosshi l l to Wal lasey – t runk and d is t r ibut ion mains



El lesmere Por t – t runk and d is t r ibut ion mains

30-Sep-12 Ongoing Undertak ing


Fleetwood – t runk main invest igat ions



Hapsford – t runk and d is t r ibut ion mains



Lancashi re conjunct ive use scheme large d iameter t runk mains

31-Mar-11 Completed

16-Jun-11 Undertak ing


L iverpool and W igan – t runk and d is t r ibut ion mains



Manchester – t runk and d is t r ibut ion mains



Manchester – t runk mains



Preston – t runk and d is t r ibut ion mains

31-Mar-11 Delayed Undertak ing


Ridgegate – t runk and d is t r ibut ion mains

31-Dec-11 Completed 24-Nov-11

Undertak ing


Riving ton – t runk and d is t r ibut ion mains



Vyrnwy – t runk and d is t r ibut ion mains


UUT Lead Dis t r ibut ion system 31-Mar-15 Ongoing Undertak ing

UUT Manganese Dee – t runk mains and d is t r ibut ion system

31-Dec-15 Ongoing Undertak ing

Northe rn reg ion

97




UUT Manganese Hodder – t runk and d is t r ibut ion mains

30-Sep-10 Completed 25-Mar-11

Undertak ing

UUT Manganese L iverpool d is t r ibut ion system

30-Jun-14 Ongoing Undertak ing

UUT Network maintenance

Haweswater – t runk main

31-Dec-16 Ongoing Not ice

UUT Regulat ion 26 Forest Farm 30-June-12 Completed

31-Mar-12 Not ice

UUT Regulat ion 26

Hunt ington

31-Dec14 Ongoing Undertak ing

UUT Taste and odour Lancaster 31-Dec-12 Ongoing Undertak ing

UUT Taste and odour Piethorne 31-Ju l -14 Ongoing Undertak ing

UUT Taste and odour Watergrove 31-Dec-12 Ongoing Undertak ing

YKS Colour and Tota l Tr iha lomethanes

Chel low Heights catchment


YKS Colour and Tota l Tr iha lomethanes Langset t catchment 31-Mar-14 Ongoing Undertak ing

YKS Colour and Tota l Tr iha lomethanes

Longwood catchment


YKS Colour and Tota l Tr iha lomethanes Loxley catchment 31-Mar-14 Ongoing Undertak ing

YKS Colour and Tota l Tr iha lomethanes Oldf ie ld catchment 31-Dec-12

Completed

31-Jan-11 Undertak ing

YKS I ron and Manganese

Rive l in d is t r ibut ion system

30-Jun-12 Completed

26-Sept -11 Under tak ing

YKS Lead Leeds d is t r ibut ion system

31-Dec-13 Ongoing Undertak ing

YKS Manganese Ingbi rchwor th 31-Mar-15 Ongoing Undertak ing

YKS Manganese Rive l in 31-Dec-12 Ongoing Undertak ing

YKS Meta ldehyde and Tota l Pest ic ides

Acomb Landing catchment



Eccup catchment 31-Mar-14 Ongoing Undertak ing


Elv ington catchment 31-Mar-14 Ongoing Undertak ing


Huby catchment 31-Mar-14 Ongoing Undertak ing


Lof tsome Br idge catchment



Tophi l l Low catchment


YKS Ni t ra te Tophi l l Low 31-Mar-15 Ongoing Undertak ing

YKS Pathogens Chapel - le-Dale 31-Mar-15 Ongoing Not ice

YKS Pathogens Concess ionary supply (11)

31-Dec-12 Completed 31-Mar-11

Not ice



Not ice

YKS Pathogens Concess ionary supply (13 )


Not ice


98






Not ice



Not ice



Not ice

YKS Pathogens Counterset t 31-Dec-12 Completed 31-Mar-11

Not ice

YKS Pathogens Hawkswick 31-Dec-13 Ongoing Not ice

YKS Pathogens Horsehouse 31-Mar-15 Ongoing Not ice

YKS Pathogens Marset t 31-Dec-12 Completed 31-Mar-11

Not ice

YKS Pathogens Oughtershaw 31-Dec-13 Ongoing Not ice

YKS Pathogens Sta l l ing Busk 31-Dec-12 Completed 31-Mar-11

Not ice

YKS Pathogens Service Reservoi r Inspect ions

30-Jun-12 Ongoing Not ice

*Dates used are those for the complet ion of the agreed programme of work. Th ere is a fur ther per iod of 12 months before a p rogramme is o f f ic ia l ly c losed to ascer ta in the benef i ts o f the work to consumers.

Delayed programmes

Company Parameter, hazard or driver

Site Reason for de lay

UUT I ron and Manganese Preston – t runk and d is t r ibut ion mains

Planning permiss ion

UUT Cryptospor id ium Concess ionary supply (5 ) Planning permiss ion

UUT Cryptospor id ium Concess ionary supply (6 ) Planning permiss ion

UUT Cryptospor id ium Concess ionary supply (8 ) Commiss ion ing issues

Acknowledged actions to sustain safe, clean drinking water

Additional acknowledged act ions

to mitigate r isk (as at Dec 2008)

Acknowledged act ions completed

(as at Dec 2010)

Acknowledged act ions completed (as at Dec 2011)

45 15 24

Northe rn reg ion

99

Annex 5 Competition in the water industry

The following table indicates the extent of competit ion in the water industry in England and Wales .

Inset appointments in place in 2011

Site Appointee Incumbent and region Status

Shotton Paper , Shotton

Alb ion W ater Dŵr Cymru W elsh W ater , Wales

Supplying water

Buxted Chicken, Fl ix ton

Angl ian W ater Essex and Suf fo lk W ater, Centra l and Eastern region

Supplying water

W ynyard, near Wolviston

Har t lepool Water Nor thumbr ian W ater, Nor thern region

Supplying water

Berryf ie lds , Aylesbury

Independent Water Networks Ltd

Thames Water, London and South East region

Supplying water

Brook lands, Mi l ton Keynes


Angl ian W ater, Centra l and Eastern region

Supplying water

Great Bi l l ing W ay, Nor thampton



Supplying water

Kings Cross, London



Supplying water

Long Crof t Road, Corby



Supplying water

Pr iors Hal l , Corby Independent Water Networks Ltd


Supplying water

The Br idge, Dar tford



Supplying water

Media City, Salford Quays

Peel Water Networks Ltd

Uni ted Ut i l i t ies, Nor thern region

Supplying water

Bromley Common, Bromley

SSE W ater Thames Water, London and South East region

Supplying water

Farndon Road, Market Harborough

SSE W ater Severn Trent W ater/Angl ian Water, Centra l and Eastern region

Supplying water

Grayl ingwel l , Chichester

SSE W ater Portsmouth W ater/Southern Water, London and South East region

Supplying water

Great Western Park , Didcot


Supplying water

Hale Vi l lage, Tottenham


Supplying water

Kennet Is land, Reading


Supplying water

Kingsmere, Bicester


Supplying water

L lani l id Park , South W ales

SSE W ater Dŵr Cymru W elsh W ater, Wales

Supplying water

New South Quarter, Croydon


Supplying water

Park Views, Epsom


Supplying water


100

Site Appointee Incumbent and region Status

Rivers ide, Bark ing SSE W ater Essex and Suf fo lk Water/Thames W ater, Centra l and Eastern region

Supplying water

The Portway, near Sal isbury

SSE W ater Wessex W ater, Western region

Supplying water

Fair f ie ld Park and Lower W ilbury Farm, Ar lesey

Veol ia W ater Centra l


Supplying water

MoD T idworth near Andover

Veol ia W ater Projects

Wessex W ater, Western region

Supplying water

New inset appointments in 2011

Site Appointee Incumbent and region

Status

Kennet Is land (Phase 7) , Reading


Appointment granted

Northe rn reg ion

101

Annex 6 Water company indices

Dee Valley Water plc Water supply arrangements

Company assets Water supplied

Number of treatment works 6 Water suppl ied (Ml/day)

66

Number of service reservoirs 31 Percentage f rom surface sources

94

Number of water supply zones 18 Percentage f rom ground sources

6

Length of mains p ipe (km) 1,857 Percentage f rom mixed sources

0

Population served Area of supply

Cheshire, Fl intshire, Denbighshire and Wrexham

Populat ion supplied 270,000

Number of local author it ies 4

Drinking water quality summary data

Company f igure Industry average

2009 2010 2011 2011

Overal l drinking water quality* 99.99% 99.89% 99.94% 99.96%

Water t reatment

Process Contro l Index 100% 100% 100% 99.99%

Dis infect ion Index 99.90% 99.87% 99.82% 99.97%

Distribution systems

Dis tr ibut ion Maintenance Index 99.92% 99.95% 99.67% 99.88%

Reservoir In tegr i ty Index 99.82% 99.97% 100% 99.96%

Building water systems

Parameters inf luenced by domest ic water systems

99.93% 99.76% 99.82% 99.87%

Consumer contacts


2009 2010 2011 2011

Informing consumers

Total number 185 155 83 N/A

Rate per 1 ,000 populat ion 0.71 0.59 0.32 1.21

Acceptabi l i ty of water to consumers

Tota l number 598 775 1242 N/A


Complaints to the Drinking Water Inspectorate

No consumers of Dee Val ley W ater plc di rec t ly contacted DWI in 2011.

Note: Summary resu l t s for each c ompany o f tes ts for i nd i v idua l parameters are supp l ied on the DW I webs i te a t h t tp : / /www.dwi .gov.uk

* Overa l l d r ink ing water qua l i t y as rep resented by mean zona l compl iance fo r 39 parameters .

http://www.dwi.gov.uk/


102

Hartlepool Water plc




34


0


100

Length of mains p ipe (km) 600 Percentage f rom mixed sources

0


Hart lepool and surrounding area Populat ion supplied 88,000




2009 2010 2011 2011

Overal l drinking water quality* 100% 100% 100% 99.96%

Water t reatment

Process Contro l Index 100% 100% 100% 99.99%

Dis infect ion Index 99.91% 100% 99.67% 99.97%


Dis tr ibut ion Maintenance Index 100% 100% 100% 99.88%

Reservoir In tegr i ty Index 100% 99.84% 100% 99.96%



99.92% 100% 100% 99.87%

Consumer contacts


2009 2010 2011 2011

Informing consumers



Acceptabi l ity of water to consumers




No consumers of Hart lepool W ater p lc d irect ly contacted DWI in 2011.

Note: Summary resu l t s for each company o f tes ts for i nd i v idua l parameters are supp l ied on the DW I webs i te a t h t tp : / /www.dwi .gov.uk



Northe rn reg ion

103

Northumbrian Water Ltd




702


82


6


12


Northumberland (Northumberland County Council) ( large part) County Durham (Durham County Council) ( large part) North Yorkshire (North Yorkshire County Council) (part) Cumbria (Cumbria County Counci l) (very small part )

Populat ion supplied 2,501,000




2009 2010 2011 2011


Water t reatment

Process Contro l Index 99.98% >99.99% 99.98% 99.99%




Reservoir In tegr i ty Index 99.92% 99.93% 99.95% 99.96%



99.85% 99.85% 99.69% 99.87%

Consumer contacts


2009 2010 2011 2011

Informing consumers

Total number 1,226 999 767 N/A



Tota l number 7,300 8,505 6,461 N/A



No consumers of Northumbr ian Water Ltd d i rect ly contacted DWI in 2011.





104

Peel Water Networks



Number of treatment works 0 Water suppl ied ( l /day)

0.275


100


0

Length of mains p ipe (km) 1.2 Percentage f rom mixed sources

0


Media City, Salford Populat ion supplied 175




2009 2010 2011 2011

Overal l drinking water quality* 94.14% 100% 100% 99.96%

Water t reatment

Process Contro l Index N/A N/A N/A 99.99%

Dis infect ion Index N/A N/A N/A 99.97%


Dis tr ibut ion Maintenance Index 91.67% 100% 100% 99.88%

Reservoir In tegr i ty Index N/A N/A N/A 99.96%



88.89% 100% 100% 99.87%

Consumer contacts


2009 2010 2011 2011

Informing consumers


Rate per 1 ,000 populat ion 0 16.67 0 1.21



Rate per 1 ,000 populat ion 0 0 0 1.91


No consumers of Peel Water Networks di rec t ly contacted DWI in 2011.

Note: Summary resu l t s for each company o f tes ts for i nd i v idua l parameters are sup p l ied on the DW I webs i te a t h t tp : / /www.dwi .gov.uk



Northe rn reg ion

105

United Utilities Water plc




1,748


83


5


12


Cumbria, Lancashire, Merseyside, Greater Manchester and Cheshire

Populat ion supplied 6,872,000




2009 2010 2011 2011


Water t reatment

Process Contro l Index 99.94% 99.97% 99.98% 99.99%







99.87% 99.86% 99.81% 99.87%

Consumer contacts


2009 2010 2011 2011

Informing consumers

Total number 2,742 1,752 1,430 N/A



Tota l number 19,645 16,315 16,246 N/A



A tota l of 3 consumers of Uni ted Uti l i t ies Water p lc d irect ly contacted DW I in 2011.





106

Yorkshire Water Services Ltd




1,281


80


20


0


Yorkshire Populat ion supplied 4,925,000




2009 2010 2011 2011


Water t reatment

Process Contro l Index 99.81% 99.99% 99.99% 99.99%







99.88% 99.92% 99.95% 99.87%

Consumer contacts


2009 2010 2011 2011

Informing consumers

Total number 2,655 2,143 2,268 N/A



Tota l number 14,536 13,578 12,043 N/A



A tota l of 1 consumer of Yorkshire W ater Services Ltd d irect ly contac ted DW I in 2011.

Note : Summary resu l t s for each company o f tes ts for i nd i v idua l parameters are supp l ied on the DW I webs i te a t h t tp : / /www.dwi .gov.uk

* Overa l l d r ink ing water qua l i t y as rep resented by mean zona l compl i ance fo r 39 parameters


Northe rn reg ion

107

Annex 7 Information relating to public water supplies published by the Inspectorate in 2011 Information Letters

Ref Title

01/2011 Amendment to The Water Supply (Water Quality) Regulat ions

2010 (Wales)

02/2011 DWI Enforcement Policy

03/2011 Publ icat ion of World Health Organisat ion (WHO) document

entit led 'Water safety in bui ldings'

04/2011 Guidance on the general provisions for monitor ing of parameters

relevant to radioactivity

05/2011 Product ion, delivery, receipt and control of water treatment

chemicals

06/2011 Technical Audit of Water Companies under Section 86 of the

Water Industry Act 1991: Publ icat ion of the report following the

audit of STS Analyt ical Services at Br idgend

07/2011 Implementat ion of the new SCA blue book 233: The

determination of taste and odour in dr inking waters (2010)

08/2011 Publ icat ion of report: Object ionable taste and odour in water

suppl ies in North-East London between January and March 2010

The le t te rs , and the i r assoc ia ted annexes , can be found on the Inspec tora te ’s webs i te a t ht tp : / /dwi .def ra .gov.uk /s takeholders / i n format ion - l e t te rs / index.h tm

Technical guidance

DWI Approval of Enterolert -DW® Quanti-Tray® method for the

determination of Enterococci in dr inking waters

Cop ies o f the above gu idance can be found on the Inspec tora te ’s webs i te a t ht tp : / /dwi .def ra .gov.uk /s takeholders /gu idance -and -codes -o f -p rac t ice /


108

Research

Ref Tit le

DWI 70/2/260 Alternatives to phosphate for plumbosolvency control

DWI 70/2/245 Investigation of instances of low o r negative pressures in

UK dr inking water systems

DWI 70/2/224 Analyt ical methods for predicted dis infect ion by -products

of probable toxicological s ignif icance

DWI 70/2/242 Evaluat ion of haloacetic acid concentrat ions in treated

drinking water (Cranf ield University)

DWI 70/2/253 Evaluat ion of haloacetic acid concentrat ions in treated

drinking water (WRc plc)

DWI 70/2/255 A review of fungi in drinking water and the implicat ions for

human health

DWI 70/2/208

WRF 4006

Crit ical assessment of implement ing desal inat ion

technology

DWI 70/2/225 An invest igation of leaching f rom f lexible r ising mains

leading from borehole pumps

DWI 70/2/189 Water Safety in Bui ldings

Copies o f res earch repo r ts and exec ut ive summar ies can be found on the Inspec tora te ’s webs i t e at h t tp : / /dwi . def ra .gov.uk / researc h/comple ted - res earch/2000todate .h tm

Northe rn reg ion

109

Annex 8 Distribution of private water supplies

North East

Local authori t ies Key


Northumber land County Counci l 1

Durham County Counci l 7

Newcast le -upon-Tyne Ci ty Counci l 2

Hart lepool Borough Counci l 8

North Tynes ide Met ropol i tan Borough Counci l

3

Dar l ington Borough Counci l 9

Gateshead Metropol i tan Borough Counci l

4

Stockton on Tees Borough Counci l

10

South Tynes ide Metropo l i tan Borough Counci l

5

Middlesbrough Borough Counci l

11

Sunder land Ci ty Counci l 6

Redcar and Cleveland Borough Counci l

12


110

North West

Northe rn reg ion

111


Carl is le Ci ty Counci l 1

Al lerdale Borough Counci l 2

Eden Dis t r ic t Counci l 3

Copeland Borough Counci l 4

South Lakeland Dis t r ic t Counci l 5

Barrow- in-Furness Borough Counci l 6

Lancaster Ci ty Counci l 7

W yre Borough Counci l 8

Blackpool Borough Counci l 9

Fylde Borough Counci l 10

Preston Ci ty Counci l 11

Ribble Val ley Borough Counci l 12

Pendle Borough Counci l 13

Sef ton Metropol i tan Borough Counci l 14

West Lancashi re Dis t r ic t Counci l 15

South Ribble Borough Counci l 16

Chor ley Borough Counci l 17

Blackburn wi th Darwen Borough Counci l 18

Hyndburn Borough Counci l 19

Burn ley Borough Counci l 20

Rossendale Borough Counci l 21

W igan Met ropol i tan Borough Counci l 22

Bol ton Metropol i tan Borough Counci l 23

Bury Metropol i tan Borough Counci l 24

Rochdale Metropol i tan Borough Counci l 25

W irra l Metropol i tan Borough Counci l 26

L iverpool Ci ty Counci l 27

Knowsley Metropol i tan Borough Counci l 28

St Helens Met ropol i tan Borough Counci l 29

Hal ton Borough Counci l 30

Warr ington Borough Counci l 31

Sal ford Ci ty Counci l 32

Traf ford Met ropol i tan Borough Counci l 33

Manchester Ci ty Counci l 34

Oldham Metropol i tan Borough Counci l 35

Tameside Met ropol i tan Borough Counci l 36

Stockport Metropol i tan Borough Counci l 37

Cheshi re W est and Chester Counci l 38

Cheshi re East Counci l 39


112

Yorkshire and Humber



Richmondshi re Dis t r ic t Counci l 1

East Rid ing o f Yorkshi re Counci l 12

Hambleton Dis t r ic t Counci l 2

Kingston upon Hul l Ci ty Counci l 13

Ryedale Dis t r ic t Counci l 3

Ki rk lees Counci l 14

Scarborough Borough Counci l 4

Wakef ie ld Metropol i tan Dis t r ic t Counci l

15

Craven Dis t r ic t Counci l 5

Barns ley Metropol i tan Borough Counci l

16

Harrogate Borough Counci l 6

Doncaster Metropol i tan Borough Counci l

17

York Ci ty Counci l 7

North L incolnshi re Counci l 18

Calderdale Met ropol i tan Borough Counci l

8

North East L incolnshi re Counci l 19

Ci ty o f Bradford Metropo l i tan Dis t r ic t Counci l

9

Shef f ie ld Ci ty Counci l 20

Leeds Ci ty Counci l 10

Rotherham Met ropol i tan Borough Counci l

21

Selby Dis t r ic t Counci l 11

Drinking Water Inspectorate | 55, Whitehall | London | SW1A 2EY | Tel: 020 7270 3370

http://www.dwi.gov.uk

Drinking Water Inspectorate | Ergon House, Horseferry Road, | London | SW1P 2AL | Tel: 0300 068 6400

www.dwi.gov.uk

PB 13776

Drinking water 2011

Public water supplies in the N

orthern region of England

Drinking water2011Public water supplies in the Northern region of EnglandJuly 2012A report by the Chief Inspector of Drinking Water

drinking water 2011 - gov.ukdwi.defra.gov.uk/about/annual-report/2011/northern.pdfyorkshire wolds....

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