Usually, water-pumping systems for diesel generator DG were used to extract the water in particular in remote areas. However, growth in the photovoltaic (PV) market and wind power make them competitive. In this context, a comparative study of three different types of pumping systems with tank storage namely PV / DG / Tank, PV / Tank and DG / Tank have been proposed. A techno-economic study of these configurations is proposed. The study is based on two concepts: the reliability by the Loss of Power Supply Probability (LPSP) model and the economic by the Life Cycle Cost (LCC). The methodology adopted suggests different procedures based on the water consumption profiles, total head, tank capacity, diesel generator buck-up system and photovoltaic array peak power. To highlight the developed models, a case study was conducted to select the best configuration, which is designed to supply drinking water in secluded and scattered small villages situated in Ghardaïa region, South Algeria. Hence, the three configurations are compared and the results shows that the hybrid PV/DG water pumping system with water tank storage is the most economically reliable configuration.