According to technical and economic criteria, a right maintenance policy must be applied to enhance the hydraulic performance and the reliability of water networks. Water networks ensure delivery of water to consumers with the help of pressured networks consisting in several hydraulic components: tanks, reservoirs, pipes, valves, and pumps. The current paper deals with the combination of a multi-objective approach based on Pareto ranking and Genetic Algorithm with a hydraulic software in order to develop a decision support model for pipes renewal. The model is based on the identification of critical pipes and assessment of maintenance costs. It ensures the work planning on pipes and the availability of financial resources at the right time and in the right way. A set of non-dominated solutions according to hydraulic and economic objectives is proposed, selection of the right one remains to the water utility manager. We propose an overview of the developed approach and we present an application on a realistic water network.