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The sources of chemical constituents of groundwater and its associated hydrogeochemical processes in the part of Mhlathuze catchment was identified. Groundwater of the area is classified into soft to very hard and the nature is identified as acidic to alkaline. The overall electrical conductivity is < 3000 μS/cm except in three wells. The predominant water type is NaCl (69% of samples) and CaMgCl facies. Gibbs plots, mCa/Mg ratio, mNa/Cl ratio, Ca + Mg vs HCO 3 +SO 4 plot, Na + K vs HCO 3 plot, Ca/Na vs HCO 3 /Na, Chloroalkaline indices (CAI 1, CAI 2) and Ca + Mg–HCO 3 –SO 4 vs Na + K–Cl plots confirm the impact of silicate, carbonate mineral weathering and ion exchange reaction in this aquifer. However, few wells are influenced by the evaporation process. Groundwater is highly undersaturated with sulphate, chloride minerals and saturated with carbonate minerals. CA revealed that Cl and SO 4 are derived from anthropogenic sources and a significant positive correlation between HCO 3 and Cl reveals that wastewater recharge has most likely simulated the mineral weathering in the vadose zone, which could have further enhanced HCO 3 and Cl in the aquifer. PCA resulted in three factors. Factor 1 defines the influence of geogenic and anthropogenic processes while Factors 2 and 3 imply the mineral weathering and nitrification processes. Hierarchical cluster analysis defines that evaporation, anthropogenic input, silicate and carbonate weathering and nitrification process are the sources of chemical constituents of groundwater in this aquifer. [Display omitted] • Ionic ratios and bivariate plots reflect the impact of silicate & carbonate weathering and ion exchange reactions.. • Groundwater is highly undersaturated with sulphate and chloride minerals while saturated with carbonate minerals. • Wastewater recharge simulated mineral weathering in the vadose zone (HCO 3 vs Cl (r 2 >0.64)) of this aquifer. • Both PCA and HCA also reflects the influences of geogenic, anthropogenic and nitrification process. [ABSTRACT FROM AUTHOR]