<p>Groundwater quality in hard rock regions is increasingly threatened by intensive agricultural activities and geological factors, posing challenges for safe drinking and irrigation use. This study evaluates the spatial and seasonal variability of groundwater quality in this hard rock basin using integrated quality indices, irrigation suitability plots, and statistical analyses for the betterment of drinking and agricultural purposes. A total of 48 groundwater samples were analyzed before (PRM) and after the monsoon (POM) to assess major physicochemical parameters and their compliance with WHO drinking water standards. The results revealed that 22% of pre-monsoon and 10.4% of the post-monsoon samples were unsuitable for drinking based on the water quality index (WQI). Key contaminants such as potassium (K⁺), nitrate (NO₃⁻), and fluoride (F⁻) exceeded safe limits in several locations. Hydrogeochemical facies, including mixed CaMgCl, CaHCO_3, and NaCl, were identified using piper diagrams, indicating a longer residence. Groundwater quality deterioration was confirmed by the 85% shift of doubtful representations in post monsoon Wilcox’s results. The quality is in a medium level was observed from 10% to 15% class II indication during pre and post monsoon in Doneen’s plot. The groundwater saltiness is observed from the predominance C₃S₁ category in the USSL diagram. There was a strong correlation between Na with Cl, NO₃, and K. All these results indicated the improper agricultural practices in this region, which highly affected the groundwater chemistry. The findings underscore the need for seasonal monitoring and integrated management strategies to ensure sustainable groundwater use in hard rock terrains.</p>