The present study was intended to calculate Water Quality Index (WQI) of a Mula River Rahuri, Ahmednagar District in order to ascertain the quality of water for public uses and other purposes. This paper deals with the study on the influence of environmental parameters on the water quality of reservoir. Water Quality Index, indicating the water quality in terms of index number, offers a useful representation of overall quality of water for public as well as in the pollution abatement programmes and in water quality management. In this study Water Quality Index was determined on the basis of various physico-chemical parameters like pH, Electrical Conductivity, Total dissolved Solids, Total Hardness, dissolved oxygen, calcium, Magnesium, Biochemical Oxygen Demand, Chemical Oxygen Demand.

Keywords: Reservoir; Physico-Chemical Parameters; Drinking Water Quality.