Laniera Plains are an area with significant groundwater resources. However, the quality of the water is highly questionable. The population of Laniera most commonly uses wells to access this resource. Nevertheless, a few boreholes have been installed to meet the water demands of some nearby municipalities. Literature reveals that the groundwater in the region is contaminated and unsuitable for consumption, posing a serious threat to public health. This study aims to identify the sources of groundwater contamination in the area and highlights the zones most exposed to pollution. Hydrochemical analysis reveals that the aquifers exhibit five predominant water types, with the most common being Na–Cl, followed by Mg2+–Cl−, Mg2+–HCO3−, Ca2+–Cl−, Ca2+–HCO3− and Ca2+–Mg2+–HCO3−. Statistical analysis shows that Cl−, Ca2+, Mg2+, NO3− and Na+ ions are strongly correlated with electrical conductivity. The saturation indices of carbonate and sulphate mineral species indicate the dissolution of these minerals, while the oversaturation of ferrihydrite mineral species suggests their precipitation. Water–rock interactions are the geogenic source of water mineralization. Intensive use of fertilizers, leaching and infiltration of domestic pollutants are identified as anthropogenic sources. This study reveals that alluvial zones are most vulnerable to contamination by iron and organic matter, whereas the crystalline basement is more vulnerable to anthropogenic pollution.