This study assesses the groundwater quality in Paramathivelur Taluk, Namakkal District, during post-monsoon and pre-monsoon seasons, focusing on physicochemical parameters such as TDS, EC, pH, hardness, chlorides, COD, BOD, sulfates, alkalinity, nitrates, and fluorides. Samples were collected from ten locations, and significant seasonal variations were observed, particularly in temperature, TDS, and nitrate levels. Post-monsoon, water temperatures increased to 38.1 - 40.1 °C, while pH values slightly decreased, indicating a dilution effect due to rainfall. Notably, TDS levels increased from 150 - 215 mg/L pre-monsoon to 310 - 480 mg/L post-monsoon, reflecting runoff impacts. The novelty of this study lies in the detailed seasonal comparison of water quality and the identification of geochemical processes through Gibbs plots and spatial maps. The findings suggest that while the water quality generally meets acceptable standards, continuous monitoring is essential to manage long-term impacts, especially on soil salinity and drinking water safety. This study contributes to the wider acquaintance of groundwater quality dynamics in semi-arid sections and highlights the need for sustainable groundwater management practices.