It is known that the groundwater quality is important as it is the main factor determining its suitability for drinking, domestic, agricultural and industrial purposes. In order to assess the groundwater quality, 16 groundwater samples have been collected from different places in cultivatedPugalur and uncultivatedPugalur during January 2012. The water samples collected in the stations were analyzed for Electrical Conductivity (EC), pH, Total Dissolved Solids(TDS), Total Hardness(TH), Total Alkalinity (TA), major cation like calcium, magnesium, sodium, potassium and anions like chloride, nitrate and sulphate in the laboratory using the standard methods given by the American Public Health Association (APHA, 2005). Water quality indices are generally used as a tool to convert a large data set into a much reduced and informative form. Water quality index (WQI) by weighing arithmetic index method is used to assess the suitability for drinking and irrigation purpose. The results were evaluated in accordance with the drinking water quality standards suggested by the World Health Organization and are presented. Chloride, alkalinity, hardness, EC and potassium were found excess in most of the samples.The results are analyzed in the light of USSL diagram and Piper trilinear plot using Aquachemsoftware.The Piper diagram showed that the groundwater was of mixed Ca-Mg-Cl type followed by Na-Cl and Ca-Cl type.
