domestic water consumption in chennai

7/25/2019 Domestic Water Consumption in Chennai

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Domestic Water Consumption in Chennai

Findings of A Sample Survey*

A.Vaidyanathan** J Saravanan***

Introduction

Most discussions of urban water supply focus on the ability of the public system to provide

certain norms in terms of per capita supply, and various technical, managerial and financial

problems of its operation. However, the public system is not the only source of supply. Someyears bac, a large scale survey of !hennai !orporation showed that the total volume consumed

per capita was considerably less than the norm of "#$ lpcd considered necessary in metropolitan

areas and that public sources contributed less than half of the total consumption. %hat

groundwater e&tracted by privately owned wells and bore wells was the main private source andthat groundwater levels in the city have been falling progressively was nown in a general way.

'ut no hard data were available. %he present survey is designed to get a fuller and more detailedassessment of systematic estimates of the overall levels and patterns of water use, the relative

contributions of different public and private sources of supply as well as the behaviour of the

groundwater table.

* %he survey is part of the !entre for Science and (nvironment)s ongoing wor on the current

status, problems and prospects of water supply in urban areas of the country.

** (meritus +rofessor, Madras nstitute of -evelopment Studies, !hennai

*** ormer !entre for Science and (nvironment staff


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Scope and Design of Survey

%he Survey, conducted during -ecember #$$/ and January #$$0, was limited to householdswithin the limits of the !hennai !orporation. !ommercial and industrial establishments and

other public and private institutions were not covered. A representative sample of "1"$

households was interviewed for collecting data. %he "11 wards in the city were grouped intothree broad categories according to the availability and reach of the public system based on

assessment by Metro 2ater officials. 2ards within each of these categories were further

categori3ed into upper, middle and lowincome neighbourhoods. %hough this was done inconsultation with several nowledgeable persons, it is necessarily impressionistic. 2e thus had

nine categories of wards.

A stratified random sampling procedure was used to select a total of "1"$ households, thenumber that seemed feasible within the constraints of time and resources available. %he number

of sample households to be selected in the 4 strata was allocated in proportion to the total

number of households in each of them 5obtained from the "44" census6 Since the ward wise

population of #$$" census was not available at the time of study7. t was further decided thathouseholds to be surveyed should be selected from a randomly selected sample of the streets

within each sample ward and that at least randomly selected "$ households should beinterviewed from each sample street. %he number of sample wards in each stratum and the

number of sample streets in each sample ward was determined on this basis. %he sample wards

and sample streets within each of them were chosen through random selection. A total of "1"$sample households in "1" streets located in /" wards were covered by the survey. -etails are

given in the annexure 1. %he location of the sample wards is shown in the accompanying map.

%he survey schedule (see annexure !was designed to elicit information of householdcharacteristics, the sources on which they normally depended for different uses, and the actual

8uantity they obtained from different sources during the day prior to the interview, particulars of

storage tans and sumps, purchase of water from metro taners and private taners, costs ofgetting water from different sources, the characteristics of wells9borewells 5including the time of

their construction, deepening and current and original depth and power source7, and

implementation of rainwater harvesting.

%he interviews were conducted from late -ecember #$$/ through January #$$0 by postgraduate

students in social wor from the Madras !hristian !ollege. %heir field wor was closely

supervised and the filled in schedules scrutini3ed by +rof. Annadurai and -r.Mirium Samuel,head of that department and Sri J Saravanan. n several cases investigators had to revisit the

households to fill in gaps and get clarifications. An effort was made to get the relevant

information from the head of households as well as female members who are far better informedabout domestic water use. Most were willing to answer all the 8uestions and give information.

However some of the 8uestions and in some cases the instructions to field investigators were notframed clearly. or instance, the 8uestions relating to 8uantum of water used from different

sources did not specify the contribution of private taners. %he treatment of multiple occupancy

households and flats raised some difficulties in estimating overall consumption and use because

the schedule did not include 8uestions on the number of households in such cases. nformation


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relating to water supply and dependence on different sources under :usual) or :normal) conditions

and in the current situation is difficult to interpret because of some ambiguities in the 8uestions.

%hese problems notwithstanding, thans to the cooperation of the informants and the effort put in

by the field investigators, the Survey has provided much valuable data to piece together a picture

of the core aspects of sources and use of water, groundwater e&ploitation and rainwaterharvesting among the sample households, as well as the variations in these features between

different parts of the city and across different income groups. %hat the estimates of total

consumption by sources and uses based on the survey data are broadly corroborated by estimatesfrom other independent sources.

(stimates of 8uantities consumed by purpose and source are based on informants) recollection of

the number of pots and bucets used the day before the interview. %hese containers are generally,but not always, of two or three standard si3es. Moreover, the information obtained is based not

on actual observation but on recollection of the respondents. %he data are therefore necessarily

appro&imate. ;evertheless, a comparison of the estimates of total per capita consumption from

the public system with the Metro 2ater figures of the 8uantity supplied during the survey periodsuggests that the survey estimates are in the right ball par. (stimates of per capita consumption

for individual uses 5e&cept perhaps toilets7 also seem plausible.

Characteristics of sample households

%he location of the /" sampled wards can be seen from map 1. %able" gives their distribution

according to original stratification by conditions of public supply and a notional assessment of

relative prosperity based on the proportion of households living in slums. %he location of the

sample wards is shown in Map ".

"a#le 1$ Distri#ution of sample %ards #y extent of pu#lic supply

and average living conditions

M(

M--?(

;!>M(

?>2(=

;!>M(

@>>- S


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"a#le & $ 'ducation and ccupation of the sample house hold head

%otal members (ducation of house hold head

Adult !hildren ;on literate (lementary Secondary -iploma -egree

B"CB #$## ""$ #"B 0"$ DB BDD

"a#le & )$ ccupation of the sample house hold head>ccupation of house hold head

Self

(mployed

=egular (mployee

>rganised Sector

=egular (mployee

f the total surveyed house holds about 0#E fall in the income group of less than =s. 1$$$ per

month, and about C percent more than =s."1$$$ per month. About B/ percent of the sample

households live in their own houses and the rest in rented accommodation. %he samplehouseholds are divided more or less e8ually between single occupancy homes and multiple

occupancy houses. About "D percent of the households live in flats. %he relative importance of

owned housing and single occupancy also varies with income. As may be e&pected, theproportion of households living in own houses and in single occupancy residences increases with

income 5%able 07.

"a#le $ Characteristics of +ouse holds %ith different income levels

Household income

group in =s.

;o. of

households

?iving in own

house

?iving in single

occupancy

F1G B$$ /$4 #01

1G "$ G /4C #B# #"$

"$G "1 G /// #"1 #CC

I"1 G 4C D/ C#

All reporting households "0#C 1D ""D%otal sample households "1"$ 4#C 4##

;ote some sample households did not provide the information. their number under each

characteristic is indicated as nonreporting

-ependence on sources

%he sources of supply as reported by the sample households, and the number of households

reporting different sources are presented in table 1. =oughly 11 percent of the sample

households have direct metro water connections6 B0 percent report accessing fi&ed tans,

taps and hand pumps provided by Metro 2ater6 and about "" percent metro taners. ;earlytwo thirds of sample households have their own wells or bore wells. Access through others)

wells and private taners is reported by less than 1 percent each of the total households. %he

fact that the number of sources is nearly double the number of households shows that!hennaities depend on multiple sources for their water supply.


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"a#le & ,$ -um#er of households reporting

different means of access to %ater supply

Sources Sample households

+ublic

-irect inhouse >utside tap9hp Storage tan

Metro taner

D/00"C01$

"CD

>wn well "$$$

>thers well 1$

!ommunity well 1

+rivate taner 01

%otal ./.

%his is further highlighted by table B, which gives the situation at the time of the survey in

respect of sources from which households draw their supplies. >nly 0$ percent of samplehouseholds report using a single source mostly wells 50$C households7, followed by metro

taners 5"CD7 and private taners 5017.

>f those who report multiple sources, by far the largest number supplement own well with othersources6 a si3eable number use metro water taners along with other sources 5again mostly wells7

%he large maKority of households depend on a single source for each purpose, but different

sources for different purposes. A si3eable proportion 5ranging from one eighths in the case oftoilets to one fifth for drining7 uses two sources. A much smaller number of respondents use the

three sources. >nly 0$ percent of sample households report using a single source mostly wells

50$C households7, followed by metro taners 5"CD7 and private taners 5017. >f those who report

multiple sources, by far the largest number supplement own well with other sources6 a si3eablenumber use metro water taners along with other sources 5again mostly wells7 5%able B7

"a#le 0$ Dependence of sample

households on multiple sources

Sources Homes

>wn 2ell and Metro taner 0B#

>wn well and >ther well #/

>wn well and !ommunity well #

>wn well and +rivate taner /"

Metro taner and >ther well ""B

Metro taner and !ommunity well C/Metro taner and +rivate taner "D

>ther well and !ommunity well "

>wn well, Metro taner L >ther well 4

>wn well, Metro L +rivate taner B

Metro L +rivate taner, >ther well "


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%he pattern of source dependence varies with income. %aing all uses together, 5see %able D7 the

proportion of sample households reporting dependence on wells as the sole source increases

progressively from about "" percent in the lowest to more than half in the highest income group6dependence on metro taners is inversely related to income the proportion being roughly a si&th

of lowest income group and practically 3ero in the "1G group6 on the other hand, dependence

on private taners as the sole source is negligible in low income groups and is relatively high 5"#percent7 in the highest. %he incidence of multiple sources does not show a clear pattern.

"a#le /$ -o of sample households #y income group reporting use from various sources

>wn well Met

taner

>ther

well

!omm.

2ell

+rivate

taner

Multiple

sources

%otal

Homes

1 B1 "$B 00 1 # #C/ B$$

1"$ "$" 01 1 $ / /4 /4C

"$"1 "$4 "C " $ #C "14 ///

"1#$ 1" $ $ $ "# #1 4C

"$1 households in the 1 group, #$0 households in the 1"$ group, #$households in the "$

"1 group and 1households in the I"1 group haven)t responded

%his is further highlighted by table D, which gives the number of households reporting use of

different sources for different purposes. %he following features are noteworthy

- +ublic supply from tap inside and outside the house is used for practically all

purposes more or less with e8ual fre8uency.- i&ed tans and taners of the public system are used for drining and cooing

far more fre8uently than for other uses

- 2ells 5own or others)7 are used mainly for washing, bathing and toilets.- +rivate taner supply is used by si3eable number of households in all uses, but more so

for purposes other than drining.- t is noteworthy that nearly a fourth of the households use bottled water for drining

and about D percent for cooing.

"a#le 2$ -um#er of sample households using different source for different uses


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%he survey data further show that households with less than =s 1$$$ per month depend on public

supply both inhouse and outside for all the daily uses. 2ater from public taners and from fi&ed

tans is used mainly for drining and cooing purposes. 2ater from private wells is used mainlyfor washing and bathing purposes. %he dependence of bottled water is very low in this group.

%his pattern is noticed in the middle groups as well e&cept that a larger proportion of them

depend on bottled water for drining. %hose in the highest income group depend on publicsystem to a much smaller e&tent than others. %his group depends more on own wells and private

taners for all uses e&cept for drining. %he dependence on bottled water is 8uite high for

drining and cooing in this group.

Storage devices

!hennai households combine use of multiple sources with the use of overhead tans and sumpsto store water. ;early 11 percent of sample households report having overhead tans 5with

capacities ranging from less than 1$$ litres to over D$$$ litres7 and somewhat over a fifth have

sumps !apacities ranging between less than "$$$ litres to over "$,$$$ litres7. %he proportion of

households reporting >H%s and Sumps is relatively higher among single occupancy households.%he incidence of these storage facilities is relatively limited in the case of households in the

lowest income group 5where about #D percent of households report >H% and barely C percentsumps7 while it is practically universal in the highest income group 5DD percent with >H%s and

C1 percent with Sumps7

"a#le .$ Distri#ution of +"s

and Sumps #y income groups

%otal

households

;o. of homes

with >H%

;o. of homes

with Sump1G B$$ "C" 0$

1G"$G /4C #D4 CD

"$G"1G /// /$$ "0#"1G#$G 4C DB C/

All "0#C D0B ///

About D/ households of the total sample of "1"$ haven)t reported on the monthly income

3atterns of %ater consumption

3er capita use

Average per capita daily domestic water consumption of sample households during the survey

period 5in -ecember $/January $07 ranged from less than #1 litres to more than "#1 litres.

About one third of the households reported consumption rate between #1 and 1$ lpcd andaround /4 percent between1$ and C1 lpcd. %he range of variation is considerably reduced if

we adKust for differences in the composition of households in terms of the proportion of

adults and children, Assuming that two children are e8uivalent to one adult unit,

"a#le & 14$ Fre5uency distri#ution of sample house holds #y level of per capita daily use

?evel of daily use in litres per day


8/18

F#1 #11$ 1$C1 C1"$$ "$$"#1 I"#1 All

+er capita ;o

of hhs 14 0C1 144 ##C ""/ /C "1"$

+er Adult


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However, as can be seen from %able "/, the mean per capita consumption is the lowest and the

proportion of total consumption contributed by public systems is the highest in wards rated byofficials as having :good) public water supply. 2ards with poor public supply also have a much

lower degree of dependence on public supply but only a slightly higher level of average. t is

interesting that the wards with moderate public supply report the higher level of meanconsumption and also the lowest proportion obtained from public systems.

"a#le 1 $ Consumption levels and contri#ution of pu#lic supply in sample %ards classified

#y conditions of pu#lic supply

!ondition of +ublic

supply

;umber of wards number of wards with

per capitaconsumption

F1$ lpcd

number of wards

where the +ublicsystem accounts for

I1$E of total use

@ood "/ 4 4

Medium "" / "

+oor C 0 #

Variations across income groups

A much clearer pattern emerges when we loo at the levels, sources and uses of water byhouseholds classified by incomes as reported in the Survey. 5%able "07 +er capita consumption

clearly increases with income. %he lowest income group consume around 1$ lpcd, and this level

increases progressively to around D$ lpcd in the "1 group. %his is largely a reflection of thefact that higher income groups consume more for washing, bathing and toilets. %he lowest

income group uses nearly a fifth of its total consumption for drining and cooing, while the top

group uses barely 4 percent. Among other uses, it is washing that seems to be the main reason for

higher level and a larger share of total consumption as incomes increase.

%able "/ +er !apita !onsumption based on =eported


10/18

1G C.C "C." "#.1 4.0 $.0 0C.#

1G"$G C.4 C.4 //.B #.1 $.C 1#.B

"$G"1G #.C "$.D 00.# 0.$ ".1 B/.#

"1G#$G 0.# ".0 1B./ B.D #./ C$.4

*e&cludes private taners.

Cost of %ater

%o get an idea on the amount spend by each hh to source water, sample house holds were ased

on the annual ta& paid to metrowater for water supply, amount spent to purchase water from

taners and bottled water.

%he amount collected as ta& per household by metro water is fi&ed as =s.1$ per month

irrespective of the 8uantity consumed per household. ther well B./ 4D/ "#

'ottled water $.D "#1 "B#

private taners 0.0 B4/ 0#

1B.B DD/B /"B


11/18

'stimates of total domestic consumption in Chennai city

%he estimates of mean per capita consumption 5overall and by maKor sources7 of samplehouseholds in different strata were applied to the estimated total number of households in each of

them. 5%able "B7 'ased on this, the total consumption of the city population from all sources

during the period of the survey wors out to #/1 million litres per day 5mlpd7 and consumptionfrom Metro 2ater sources to D$ million litres per day.

"a#le 10$ 'stimated daily consumption #y source7

Chennai Corporation 8anuary 44 (millon litres!

Source !onsumption E share

Metro in house #C.D "".D

Metro outside

house 1# ##.">wn wells9

borewells "#/./ 1#.0>thers) wells #D./ "#.$

'ottled water /.4 ".C

%otal #/1./ "$$.$$

At the time of the survey, Metrowater accounted for a little over a third of the total

consumption. Surface sources being practically dry during this period, supply through the public

system was entirely from groundwater e&tracted from wells bore wells and tube wells within thecity limits and from wells outside. %hough the survey was carried out at a time when there was

no piped water supply, houses in some wards located in close pro&imity to the distribution lines

got inhouse supply to distribution mains. %he greater part of public supply was providedthrough fi&ed public tans, mobile public taners and public hand pumps located outside

consumers) premises.

Sources other than Metrowater which includes private wells and bore wells, private taners

and bottled water accounted for about two thirds of the total domestic water consumption. %he

bul of it was from private wells owned by users. 'ut a si3eable amount 5#D million litres7 wastaen from wells owned by others or from community wells.

Altogether 4D percent of the total consumption was contributed by groundwater. %he balance is

accounted by bottled water.

(stimates of mean per capita consumption 5overall and by uses7 of the city)s population are

presented in %able "C. 'ased on this, the total consumption of the city population for all usesduring the period of the survey wors out to #11 mld


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"a#le 1/$ 'stimated Daily %ater consumption for various uses

n this basis we estimate

that there are about 0.# lah wells 5 about #C,$$$ open wells and nearly 0 lahs of borewells7 in


13/18

!hennai city. %he average no. of persons per household wors out to 1.# members per house

hold. !onsidering an average per day e&traction of about 0$$ litres per well per day then the

daily e&traction wors out to about "BD.4 M?-. Also the e&traction calculated based on sourceswise consumption 5for wells and borewells7 wors out to about "C$ M?-.

Characteristics of %ells and their usage

3articulars of %n Well

%he particulars of own wells ie., open dug wells and borewells present in the surveyed

households were classified based on the reported income 5%able "D7. n general the no. of

borewells is more than the open dugwells which is an indication of tapping water from the

deeper source. >f the reported households DE of them have open wells which are still in useand 10E depend on borewells. About C.1E have both open well and borewell. %he ratio of no. of

well per house hold was calaculated for all the income group. %he poor income group have one

well for every # households 5with more dependence on the public system7 and the rest of the

groups have almost a well in each household.

"a#le$ 12

;o. of household

reporting

>2 >2 in


14/18

"a#le 4$ Characteristics of %ells #ased on 9ifting Device7

"ype of 3ump and +orse 3o%er of 6otor

;o. by type of lifting device;o. by type ofpump ;o. by type of H+

Manual (lectric !entrifugal Jet $.1H+ "H+ ".1H+ #H+

1G 01 "1C #1 "C$ 1" CB #" $1G"$G "C #01 "C #C0 #/ "1B 1C $

"$G"1G "/ ##1 "1 #1" ## 4D C1 1

"1G#$G # B# 0 D$ 0 "B 0$ BCC BD4 B" CC1

%he wells were classified based on the type of lifting device 5manual and electric7. Manual

e&traction is an indication of shallow water table. >nly "$E of the wells are used for manuale&traction the rest of them are electric driven.

%he wells were also classified based on the type of pump. %he woring head 5water pulling

capacity7 of centrifugal pumps is only /$ft below ground level whereas the Jet pumps wor up to#$$ft. here again more than 4$E of the wells are fitted with Jet pumps is an indication of tapping

water from deep water table.

%he classification of Motor based on H+ also shows similar trend with more wells falling the "hp

and ".1 hp motor which is normally used to pump water from depth between "$$ft "1$ft.

%he Sample households were ased about the year of construction of the wells, their original and

current depth. %he information for open wells is presented in %able #"7## and those relating to

bore wells in %able #/,#0. 2hile most could give information on year of construction and currentdepth, many either did not now or could not remember the original depth. About /B$ sample

house holds reported to have open wells of which B1E of them were not in use. More than three

fourths of the wells were constructed before 4$. the average depth of the open wells is about /$feet below ground level. Most of the borewells were constructed after "44$ with their average

depth around 4$feet below ground level.

"a#le$ 1 :ear of Construction of pen %ells %ith their mean Current and riginal Depth

ear of !onstruction Mean -epth

;o. of wells ;o. reporting >riginal !urrent

'efore "4C$ /1 "$ #C.0 #D./

C$ D$ D/ 0D /0." //./

D$ 4$ DD 0C #4.4 #C."

After 4$ /D #/ /"." #C.C%otal #00


15/18

"a#le $ :ear of Construction of pen %ells %ith the fre5uency distri#ution of depth

ear ofconstruction

re8uency -is. >f >pen 2ells bydepth5ft7

, ,4 /, 144

'efore "4C$ C C $ $

C$ D$ "4 // 0 #D$ 4$ #0 #0 0 "

After 4$ "/ 4 # #

%otal B/ C/ "$ 1

"a#le $ ) :ear of Construction of ;ore %ells %ith their mean Current and riginal Depth

ear of !onstruction ;o. of'orewells

Mean -epth

;o. reporting >riginal !urrent

'efore "4C$ "$ 4 11.1 B1.1

C$ D$ #$ "0 DC.1 4#."

D$ 4$ "40 "## 4$." 4/.1After 4$ BB0 0## 4#.C 40."

%otal DDD

"a#le $ :ear of Construction of pen %ells %ith the fre5uency distri#ution of depth

ear of

construction

re8uency -is. >f 'ore 2ells by

depth5ft7

,4 144 1,4 44


16/18

considerable amount of initiatives taen by the state government in controlling the commercial

e&ploitation of groundwater. %he !hennai groundwater regulation act, which was passed in "4DC,

was mainly to curb the commercial groundwater e&ploitation within the city limit. %his wasfollowed by maing rainwater harvesting 5=2H7 mandatory in multistory buildings. -uring

#$$" =2H was made mandatory for all the new buildings and in #$$/ it was made compulsory

for all the buildings 5e&isting and new7 through an ordinance. 'ut the general opinion about theimplementation of this ordinance is that

the time frame given was too short

the structures were not properly designed

not many trained and silled labours were available for implementation

non availability of 8uality materials for implementation

Hence the households were ased to report on the design, implementation, cost and maintenance.

About 4#E of the surveyed households have reported =2H implemented out of which aboutDBE of the households implemented after the promulgaion of ordinance 5ie., after august #$$/7

and about 1E before #$$#.

2ith regards to the guidance sought to design the =2H system, nearly ""E got it designed withthe help of Metro water, "#E of the sample households got it designed through consultants.

airly large amount of of households 50"E7 sought the help of local plumbers in designing and

about #0E self designed their own =2H system. B1E C$E of the households haveimplemented rwh designed by plumber or self is an indication of

". non availability of e&perts in designing nor the e&perts help was sort for designing

#. 8uality of rwh structure 5in general households in !hennai opted for the normal bore typepercolation pit which is cheaper but gets clogged and hence ineffective7

"a#le$ 3ercentage of sample house holds reporting on the help sought from different

agencies for designing =W+ system in their housesAgencies Approached by E of

house holds to get=2H design

Metro 2ater ""E

;@> $E

>ther !onsultant "#E

+lumber 0"E

Self #0E

MaKority 5BBE7 of te sample house holds got the system implemented through plumbers. About4E engaged authori3ed contractors, $." E on Voluntary ;@>)s and about ""E depended others

to implement.


17/18

"a#le $ 3ercentage of sample house holds reporting on the help sought from different

agencies to implement the =W+ system in their houses

Agencies

Approached by E of

house holds to get

=2H design;@> $."E

Authorised !ontractor D.BE

+lumber BBE

>thers ""E

2ith regard to the cost of =2H about 4E have spend less than =s."$$$, /"E have spend

between =s."$$$ to =s.#$$$ to get the structures installed. About "BE of the householdsreported spending between =s.#$$$ =s. /$$$ and an e8ual percentage reported spending more

than =s./$$$ to get the structures implemented.

!ost of =2H

!ost in =s +ercentage of

Households

I "$$$ 4E

"$$$ #$$$ /"E

#$$$ /$$$ "BE

I /$$$ "1.BE

;on reported #D.0E

MaKority of the households 5more than /90 th7 reported tapping roof top water. Just "$E of the

house holds have reported tapping surface run off.

House holds reporting on the source of harvested water

Source +ercentage of

Households

=oof 2ater C4E

Surface 2ater #E

'oth DE

;on reported ""E

2ith respect to designs as shown in the table below about 1# E of the sample house holds havedesigned a proper system wherein the roof top water diverted to recharge well, percolation pit or

stored in sumps. About "$E of the households have reported faulty structures. %he rest have not

reported on the design aspects.


18/18

"a#le$ Design characteristics of =W+

=2H -esign +ercentage of SampleHouseholds

=oof top directed to e&isting >29'2 /DE

Surface water directed to e&isting >29'2 0E

=oof top to recharge well 4ESurface water to recharge well $.BE

=oof top to percolation bore pit "0E

Surface water to percolation bore pit ".1E

=oof top to percolation pit #0E

Surface water to percolation pit 0E

=ooftop to sump thro filter 1E

Surface water to sump thro filter $.DE

>f the total sample house holds #DE were aware of the maintenance re8uired in =2H structures.

;early 01E of the households were not aware of the maintenance aspects and ##E have not

responded.

domestic water consumption in chennai

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