Water network performance is defined as the ability to deliver a required quantity of waterrnunder sufficient pressure and an acceptable level of quality. Systems that have bigrntransmission line may have problem on changes of pressure in the distribution system.rnBecause pressure rate changes have been too much between water treatment plant and deadrnends in distribution system. This study is to analyze the effects pressure changes on the waterrnquality in water distribution systems for case study of Akaki phase 3B water supply systemrnwas assessed. Efforts were also made to identify the relationship between the residualrnchlorine and pressure in the distribution of the water supply network systems using WaterrnCad software /tool to model water distribution system. rnAccordingly, simulation results show that, for maximum and minimum pressures were usedrnas base to evaluate the hydraulic performance; and simulation results for minimum residualrnchlorine were used as base to assess water quality transformation in distribution system.rnPressure has a direct relationship with residual chlorine. Pressure change has been causing tornincrease chlorine consumption more. The result of pressure changes among others canrndecrease in chlorine content and hydraulic factors, because the systems may be extensive andrnthus possess complex networks and hangs in quantity cause pressure of flow. Hencernhydraulic changes (pressure) could affect of water quality in the water distribution system.