WDN operation involves two main issues: pipes rehabilitation and reduction of NRW; both with large economical repercussions. This paper presents an algorithm developed by CIACUA which selects the most important pipes to be replaced in terms of reducing power dissipation inside WDN. Additionally, it finds an optimal alternative for WDN operators to plan system's rehabilitation in terms of the enterprise's economic benefits. This paper includes analysis of two case studies of WDN, one with a regular topography and another with strong topographic variability. In both cases the methodology proved successful.