Present paper deals with the chemical quality of groundwater in the Deccan basaltic aquifer. The Deccan basalt is an igneous rock form by the molten rock material called as magma/lava. Rock is an aggregate of minerals and every mineral has its own fix chemical composition. Chemical composition of basalt reveals SiO2, as major component (48 to 49%), along with the other major chemical components as Al2O3 (13 to 15%), Fe2O3 (12 to 15%), MgO (5 to 7%), CaO (10 to 12%). Minor chemical components comprises Na2O (2 to 3%), K2O (0.1 to 0.5 %), TiO2 (2 to 3.5 %), P2O5 (0.1 to 0.3 %) etc. Results of the hydro-geochemical analysis of groundwater samples from Pewtha area reveals TDS 856 mg/l, Na+ 94 mg/l, K+ 12 mg/l, Ca+ 80 mg/l, Mg+ 77 mg/l, HCO-3 244 mg/l, Cl- 188 mg/l, SO42- 98 mg/l, NO3- 90 mg/l and F- 0.90 mg/l. The careful observation of chemical components and correlation reveals that most of the elements in groundwater are inherited from the chemical composition of the host rock (basalt) and some are due to anthropogenic activities. Thus, present study demonstrate the dominance of chemical components from parent rock, which dissolves in the groundwater and which can vary from place to place depending on rock types.