Groundwater quality of Tamilnadu in Ramanathapuram District needs attention for alternative source of water for domestic and agricultural purposes because it is one of the coastal region. Groundwater totally thirty samples were collected from different locations in and around Ramanathapuram District for the period of November 2021 (Monsoon) and analyzed for their physicochemical parameters. The water quality assessment has been carried out by evaluating the physicochemical parameters such as Hydrogen ion concentration (pH),Electrical Conductivity (EC), Total dissolved solids (TDS), Dissolved Oxygen (DO)), Biological oxygen demand (BOD), Chemical oxygen demand (COD), Sulphate (SO4), carbonate (CO3), Bicarbonate (HCO3), Nitrate (NO3), Phosphate (PO4), Total Hardness, Calcium (Ca), Magnesium(Mg), Sodium (Na), Potassium (K), Chloride (Cl) and Fluoride. The main objectives are to study about by using the water quality index and USSL diagram whether it is suitable for drinking and irrigation or not.