Stable isotope and Hydro-geochemical methods have been used to characterize groundwater in the Ga West Municipal Area of Ghana. Residents in the municipality mostly depend on groundwater for their water needs. However, high salinity groundwater obtained in the area poses difficulties for current water supply as well as future exploitation. Schoeller and Piper plots have been used to characterize the groundwaters to determine the sources of salinity. The dominant groundwater composition in both shallow and deep wells sampled is Na-Cl, with concentration increasing substantially with well depths. The mixing process between freshwater and saline water was observed in the shift from CaHCO3 facies to Ca-Cl facies. Stable isotope composition of the groundwater suggests that groundwater recharge is of meteoric origin. An average deuterium excess of rainfall of 14.2‰ was observed, which indicates the significance of kinetic evaporation due to low humidity conditions prevalent in the study area. The d-excess also indicates modern recharge along the Akwapim-Togo Range of mountains.