Design Period of Water Supply Scheme:

Water supply projects are designed to serve over a specified period of time. This useful life time after completion of the project is called "design period". It is expressed in years. During design period, the structures, equipment and components of the water supply scheme are supposed to be adequate to serve the requirements. Generally, the water works are designed for a period of 30 years. Following factors are considered while taking a decision on design period of water supply schemes:

(a) Useful life of pipes, equipment and structures.

(b) The anticipated rate of growth. (If rate is more, design period would be less.)

(c) The rate of inflation in during a period of repayment of loans. (When inflation rate is high, a longer design period is adopted.)

(d) Efficiency of component units. (The more the efficiency, the longer will be design period.)