The paper presented to study of the Physico-chemical Parameters of Cuddalore District, Tamilnadu. Yearly-wise changes in physical and chemical. Parameters such as pH, EC, TDS, Hco3 , F, Cl₂, SO₄, NO⁻₃, Na⁺, K⁺, Ca²⁺ and Mg²⁺ were analysed for a periods of year from 2009 – 2013. All Parameters were exceeds the permissible limit except Ca and SAR