Groundwater in the semi-arid region of Dharapuram, southern India, is increasingly affected by nitrate and other chemical contaminants due to both natural and anthropogenic activities. This study aims to assess nitrate contamination and its associated health risks in the region. Total dissolved solids, nitrate, and fluoride levels exceeded permissible limits in 11.76%, 32.35%, and 23.53% of samples, respectively. Gibbs and Piper diagrams indicated that rock-water interactions, evaporation, and mineral dissolution play key roles in groundwater composition. Principal Component Analysis identified geochemical processes, and agricultural runoff as major factors influencing groundwater quality. Dendrogram analysis showed distinct clustering, with ionic strength dominating groundwater chemistry, while pH and fluoride behaved independently. Correlations were observed between EC, chloride, sodium, and sulphate. The Entropy Water Quality Index classified 45.59% of samples as poor, 13.23% as very poor, and 2.94% as unfit for drinking. The Nitrate Pollution Index identified 10.29% and 17.64% of samples as significantly and very significantly polluted, respectively. Nitrate levels were especially high in shallow aquifers, with 16.18% of samples containing 45-100 mg/L and 8.82% exceeding 100 mg/L. Health Risk Assessment (HRA) results revealed that the THI >1 for children (64%), Teen (44%), Women (35%) and Men (30%). Children are particularly vulnerable to nitrate exposure, with risk indices surpassing safe thresholds in some groundwater samples. The study underscores the urgent need for targeted nitrate mitigation and sustainable groundwater management strategies.