Water purity is the major concern and safe water is a primary need for human being. Industrialization has led to pollution of natural sources and ground water is not an exception. The present work is to detect the quality of ground water for Thanjavur District, Tamilnadu, India and classify the suitability of water for drinking. The chemical parameters of water such as Ph, EC, HCo3, Cl, SO4 and TDS were used for classifying using data mining techniques. The data mining classifiers support for faster identification of water quality.