Expression for Drinking Water Supply Standards

Abstract

Various authorities and regulating agencies have set standards for deciding the suitability of a water for drinking purposes. These standards prescribe the permissible concentrations of quality variables. When some variables exceed the permissible levels, a decision for permitting further use of the water supply has to be based on the importance of those variables with exceeded concentrations. It is proposed that standards for a drinking water supply should be set through a single number representing the integrated effect of all the variables, keeping due regard to the importance of each variable. Such an integrated water quality index (WQI) would help in decision making. Models and curves have been presented to evolve a WQI for drinking water supplies. It is suggested that water with a WQI lower than 90 should not be permitted. The acceptable quality therefore, should be in the 90–100 range of the WQI.