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Abnormal pattern of water consumption - possible reasons ? Bangalore, India

I live in an apartment complex in Coxtown, Bangalore (Purva Park) composed of 3 blocks, with a total of 414 flats. Most of the flats are 2 bedroom, some are 3 bedroom, the average no of persons per flat could be taken as 3.5. We are finding a funny pattern in the water consumption:
Block   No. of occupied flats   Total per day water consumption (average, thousands of liters)

  • R        122                     92KL
  • T        106                     121KL
  • D        129                     94KL

As can be seen from the above, T block with the least no of occupied flats has the largest water consumption. The per flat daily water consumption is therefore as follows:

  • R - 754 KL
  • T - 1141 KL
  • D - 728 KL

As part of a water conservation drive, we are trying to understand the significantly larger per capita water consumption that T Block is seeing. Could the water practitioners on this list suggest possible reasons for this discrepancy ? It seems unlikely that residents of that block are consuming so much more than other blocks. Is it  possibly a leakage of some sort rather than water consumption by the apartment residents ?

Thank you,
Vijay Krishna 



1. This is an "outlier", i.e. a

This is an "outlier", i.e. a data value that is not homogeneous with the rest of set. This is either due to a measurement error, or a leakage. But a leakage in the pipelines within the building is unlikely to be so large as to cause so much water loss, without being outwardly visible. More likely, either an unoccupied flat has tap left open, or some cisterns are defective, and are leaking water continuously through the commode (quite common) or has a defective ball valve and is wasting water by overflowing (less common).

Chetan Pandit

2. Abnormal pattern -causes

Dear Vijay,

I fully agree with Mr Pandit on those being an outlier.

Our experience in attending to similar  problems in the field have shown, that where ever hard water is being utilized there is a possibility of leaks being developed.

Most obvious, but which goes unnoticed is that of the Cisterns leaking, due to the rubber seat getting a coated with CaMg deposits, and these continuously leak out through  the commode.

It could be possible that one of the flats which is unused has one of the taps that is leaking or not shut properly.

The Third possibility is that there is a very small leak in the feeder line to this building.

You have measured water being supplied to this building or have you measured the water being used by the tenants of this building.

Though, both these on the face of it seem to be the same, the difference is if you measure the quantity being pumped to this building by putting a water meter at the point from where water is being pumped this is the total water being supplied to this building. When you measure the water at the outlet point from the OH tank downwards it is the water being utilized by the building.

There could be a loss due to leakages in this portion, this will go unnoticed if you have soft rock terrain which has high transmissivity and/or unsaturated.

To determine the first two is quite simple, ask every one to shut off all the taps in the building for 15 minutes, and just walk around the building and open the drains covers around the building at the point where the building water comes down ground near the building, if you see flowing water in the chamber , one of the toilets, bathrooms. kitchen etc  which is connected to this drain pipe has a leak or open tap.

If this exercise yields negative result, then you need to check the main feeder pipe from the pump to the bulding OH tank.

This is an expensive exercise, I will advice that you are dead sure that the resident' of the building are really not using the extra water for some reason or the other.

It could be that they are in a habit of filling water in containers, which they empty every day when they get the fresh supply, this is also a very common practice followed by many people in our country.


Anil LAlwani

3. Abnormal water consumption by Purva Park Apartment Complex

Dear Vijay,
As rightly pointed out by Chetan Pandit, the discrepancies in water consumption in your Purva Park apartment complex in Coxtown are due to errors in water measurement and water leakage.

If you are really serious with water conservation in your apartment complex, you should persuade your builder/flat owners/residents to install accurate water meters to record the total quantum of water supplied to the complex and the actual water consumed by each flat. The present practice of charging water on flat basis should be abandoned. Just as electricity consumed is charged on the basis of actual consumption, water also should be charged on the basis of actual consumption. This was the practice followed in India before independence, while this is followed even now in many countries in the world. It is worthwhile for the Corporation of Bangalore to make a beginning in this direction by making it mandatory by all apartment complexes to install water meters.

Once this is done, residents in the flats will strive for reducing their water bills by conserving water use and plugging water leakages. The personnel in-charge of water supply will make efforts to reduce unaccounted water not reaching the residents.
This not only provides an explanation to the abnormal pattern of water consumption but also brings down abnormal water consumption by Purva Park Apartment Complex to the relief of the neighbouring residents starving for water.

Good luck in your efforts

Dr. R. Jagadiswara Rao, Professor of Geology Retired, Sri Venkateswara University, Tirupati, AP 517502, India

4. Dear Vijay, From the data

Dear Vijay,

From the data provided, we could presume that there may be untraced leakages in water supply connections in T block or in real sense the individual flat owners may be using more water. If each house is having water meters (electronic), then we could think of regulating the quantity. More over, if we know the per flat used water (wash and bath water), they could think of putting Decentralised Waste Water System (DEWATS) for recycling them. In this regard, the person could approach CDD Society Bangalore for technical advice.


Chief executive
DHAN Vayalagam (Tank) Foundation
Madurai, Tamilnadu

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