Groundwater samples collected at different locations in and around Namakkal were analyzed for their physicochemical characteristics. Ten locations of groundwater samples were collected and studied for every two month for the period June-2007 to December-2007. The present investigation is focused on the determination of physicochemical parameters such as temperature, taste, turbidity, electrical conductivity, pH, hardness, total solids, total dissolved solids, total suspended solids, chlorides, sulphate, nitrate, fluorides, dissolved oxygen, sodium, potassium and E.coli bacterium. Groundwater suitability for domestic and irrigation purposes was examined by using WHO and BIS standards, which indicate the groundwater in a few areas, were not much suitable for domestic and agriculture purposes. Thus the objective of this study is to identify the quality of groundwater especially in the town and near by town where groundwater is used for domestic and agriculture purposes is discussed.