El-Dabaa area in north western coast of Egypt has been selected for construction of a nuclear power plant. Several geological and meteorological studies were done and there is a need for more investigation for studying the hydrological system. This study presents results of hydrogeochemical studies to get an understanding of chemical evolution of the ground water and to gain insight into the interaction of ground waters with environment. Samples from surface and ground water were collected and analyzed for chemical and environmental stable isotopes (18 O, deuterium) as well as radioactive tritium contents. The results indicated that the east Mediterranean rain water represents the main recharging source of ground waters and points out to in-homogeneity of the aquifer in addition to different recharging conditions due to permeability variation of bearing formations