The high cost generated by the pumping stations of the water supply systems has brought great concern to the concessionaire companies in the sector. Improvements to increase the efficiency of these systems and, consequently, the reduction in the costs with electricity have been the objective of several researchers and technicians responsible for the sector. Given the large number of elements that compose these systems, finding the best operational rules is many times a complex activity; therefore, all elements must be considered. In this context, the present work presents an optimization model based on the genetic algorithms that combines the efficient use of reservoirs with the best operational rule for activating pumping systems, better dealing with the restrictions of the problem. The results obtained indicated that, with better use of the water storage infrastructure, it is possible to reduce the costs with the electricity of the system as a whole.