Nov 14, 2011

Definition of “Per Capita Consumption” need to be modefied - Water Sector

By- Anoop Jha

Apparently “per capita consumption” figure is used in financials, estimates and projections of every project, and DPRs across the country and across the sectors, but apparently age old definition (Per Capita Demand in litres per day per head) and formula of “per capita consumption” seem to be flawed and vague. Let’s consider Water Sector for example.

There are few reasons for this apparently flawed 

First, this formula invariably assumes that all the water is being consumed at household, institutional or community level for some useful purpose, but that is not the fact. The fact is “the collective water losses at household and institutional level are huge in any given community, settlement, or housing society”, leaking taps, pipes due to “lack of maintenance and willingness to maintain” and water wastage related to casual behavior of users “due to lack of education and sense of responsibility”  are a regular phenomenon of almost every household. Planning bodies and Policy makers have to understand that unless they stop these water losses or unless they change the definition from  “Per capita Consumption” incorporating the water losses, there demand estimates, future projections, projects cost estimates, will inevitably  be vague and skewed,

Some interesting extract from the discussion on “India Water Portal” ( on the similar subject are as follows-

“ When the norm for a large city is 250 lpcd, it doesn’t mean the residents actually get or use 250 lpcd. A large city has many other water needs such as public use in offices, railways stations, commercial places, for fire fighting, public horticulture, etc. All these are distributed over the population and indicated as per capita use” - Chetan Pandit
“The norms do not take in to account the climate. No distinction is made between Delhi that has a huge water requirement for desert coolers in summer and a bath twice a day is not a luxury; Pune that uses some coolers but not as common as Delhi and usually bath once a day is enough; and Copenhagen where the maximum summer temperature in 17 C and most of the time it is below 10 C” -Chetan Pandit

“Water consumption is affected by various factors which are variable and hence it is difficult to precisely assess the demand of public. There are empirical formulas available for estimating a fair value of domestic consumption for design of water supply systems. However, Indian Standard (BIS):1172-1993 is the basis of 135 litres/capita/day. This 135 litres/capita/person includes drinking (5 litres/capita/day), Cooking (5), Bathing (55), Washing of clothes (20), Washing of Utensils (10), Washing & Cleaning of house (10) and flushing of toilets (30 litres/capita/day)” - J.Harsha

Second, basis, thumbrules, lifestyle, requirement and related values for arriving at “standard per capita water consumption” in different urban areas changes in courses of time and cahnge as per seasonal variation which need to be accounted for calculation per standard water consumption” Standards need to be revised after a certain time interval.

“Details of present norms for water consumption are available in CPHEEO Manual on Water Supply and Treatment and Per capita water supply in selected urban centers of India is available at Water Supply, Sanitation and Solid Waste Management in Urban Areas by National Institute of Urban Affairs, 2005”

Third, accuracy of standard per capita water consumption figure is directly proportional to the size of sample (no. of household) surveyed, which may vary from agency to agency which prepares the report. Larger the sample more realistic the results would be. There should be Policy norms for minimum size of sample to be surveyed and heterogeneity of the sample.
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