How much water does an urban citizen need?
Understanding how consumers are responding to water availability will enable better design of systems and result in efficient use of water. Our cities need to respond urgently, says water activist S. Vishwanath.
In India, the design of water supply systems has been done using certain standards. Currently the standard being used is BIS 1172: 1993, reaffirmed in 1998. This specifies a consideration of use of the following:
For communities with a population of between 20,000 to 100,000 — 100 to 150 liters per head per day.
For communities with a population of over 100,000 — 150 to 200 liters per head per day.
In its previous avatar there was also an attempt made in IS 1172 to understand the break-up of this demand which was then put as 135 liters per person per day. The break-up was as follows:
It is up to each one of us to say whether these numbers ring true. However, a detailed indulgence has to emerge for ‘true water demand’ to be understood and thus for systems to be designed with a desired outcome which can be of two kinds:
(a) Ensuring that standards are met so that public and individual health and hygiene is maintained
(b) Outcome could be to drive water efficiency when the actual demand exceeds this standard.