Exposure to radioactive elements or having them through drinking water causes many biological risks.Therefore, it is important to investigate the drinking water especially in regions where people depend on well water for drinking. Concentrations of some radionuclides in some water wells, in Arar city of Saudi Arabia, were measured by using Hyper Pure Germanium (HPGe) Detector. Concentrations of 226 Ra (Radium), 232 Th (Thorium) and 40 K (Potassium) were measured in drinking water of 5 water Selling Stations from different water wells; Alshark, Alsahab, Ghdeer, Katr Elnada and Almohamadia. The radiation hazard indices of water were also calculated. The results showed that the average values of either radionuclides concentration or radiation hazard indices of all water stations under study were in the internationally permissible range. Results therefore emphasize that the investigated wells from which the water was taken are suitable for drinking concerning the measured radionuclides. The work recommends more studies to investigate another radionuclides might be present in the drinking water.