Kidney stones or renal calculi or Nephrolithiasis is a common health problem in both developed and developing nations [1,2]. Analysis of the chemical and physical properties of renal calculi helps in preventing their formation and treatment. In this study, we evaluated the hardness of water used for drinking purposes, in an attempt to correlate water hardness with an increased incidence of stone formation. Identifying risk factors help to develop a preventive strategy to reduce the risk of renal calculi formation. The incidence of kidney stone formation in Vellore district was correlated with the hardness of water samples taken from different areas in Vellore. The study can be employed at a larger demographic level for effective and economic monitoring of the risk of kidney stone formation.