Water Quality Index (WQI) is a statistical tool used to transform large quantities of water quality data into single number which represents water quality level. This research work is accomplished to evaluate the quality of groundwater in Veppanthattai block for the purpose of drinking and domestic usage by using Water Quality Index (WQI). WQI requires several parameters to satisfy the calculations. The groundwater samples were collected from 44 different locations of Veppanthattai block during Nov 2012 to Dec 2012. Physicochemical parameters namely pH, Electrical Conductivity (EC), Total Dissolved Solids (TDS), Total Hardness(TH), Total Alkalinity (TA), Calcium Hardness (CH), Magnesium Hardness (MH), Chloride, Sulphate, Nitrate, Iron, Dissolved Oxygen(DO), Chemical Oxygen Demand (COD) and Phosphate were assessed to calculate the WQI. The present study indicates that the quality of groundwater in most of the samples is poor in quality for drinking purpose.
