Measuring the hydraulic performance of water distribunon network (WDN) is one of the difficult issues facing the water supply industry today. The system for measuring hydraulic performance in WDN used in this paper, is based on three parameters. Extended period simulation analysis for the network, modehng of penalty curves for the design criteria, and performance indexes computation. A system of penalty curves for pipe flow velocity, nodal pressure head and its fluctuation, and nodal chlorine residual is used to assess the performance of a real WDN over 72-hrs extended period simulation. The methodology gives the designer very useful tools for operation, design, planing, and rehabilitation of WDN.