The chemical properties of groundwater and the quality of drinking water have been investigated in the current study. In the Karur district, ten groundwater samples were taken in June 2023, during the southwest monsoon. The pH, electrical conductivity, total dissolved solids, bicarbonate, chloride, sulphate, calcium, magnesium, sodium, and potassium were measured in the water samples. The outcomes were assessed and compared with WHO water quality requirements. The correlation matrix indicates that Na+, Ca2+, and Mg2+ and Cl- have an impact on the basic ionic chemistry and also suggests that the samples contain Na+–Cl-, Ca2+–Cl-, and mixed Ca2+–Mg2+–Cl- kinds of water. Additionally, a thorough investigation was conducted in the research area to determine the Water Quality Index (WQI)-based drinking water quality during the southwest monsoon season. Only four blocks were found to be potable for drinking according to the WQI results.