Groundwater is the primary source of drinking water at the Vellore district, which is also the source of industrial and agricultural demand. This chapter aims to evaluate the Taluk-wise groundwater quality (GWQ) and heavy metal (HM) impacts in the Vellore district using the water quality index (WQI), heavy metal pollution index (HMPI), and multivariate statistics. In total, 25 samples were collected and analysed for physiochemical parameters and HM as per American Public Health Association (APHA) guidelines. The history data analysis reveals that Vellore, Gudiyatham, and Anaicut Taluk have had elevated physicochemical concentrations due to anthropogenic activities. The Vellore District's groundwater hydrochemistry is influenced by ion exchange and precipitation, and the groundwater types are Na–HCO3 (44%) and Ca–HCO3 (52%), based on the Chadha diagram. TDS, Cr, Pb, Zn, SO42−, Ca2+, and Na+ show a high correlation, exhibiting a huge impact on GWQ. Based on the Piper plot, the groundwater is more saline (Na-Cl type), whereas precipitation dominates according to the Gibbs plot. According to HMPI results, Cd, Zn, and Pb are discharged along with industrial wastewater. Anaicut Taluk has a high GWQ for domestic and agricultural use, while Katpadi, Vellore, Gudiyatham, and Pernambut Taluk have very poor GWQ. Cd (96%) and Pb (43%) are beyond the permissible limit, causing carcinogenic effects in Pernambut, Vellore, and Katpadi Taluk’s residents. According to vulnerability analysis, Pernambut, Katpadi, and Gudiyatham are highly vulnerable. Vellore is moderately vulnerable, and Anaicut is less vulnerable. Ensuring amendments and new policies and guidelines will lower vulnerability and enhance general health.
