Water distribution systems are designed to fulfill all requirements of potable water needed forrnintended purposes. Initial system designs frequently consider any anticipated changes likely tornhappen. However, as time elapsed they slowly begin to fail to satisfy customersâ€™ requirements,rnboth in quantity and quality. The main issue is to identify factors which bring those changes andrnpropose viable solutions to improve the situation. To this effect modeling water supply distributionrnnetwork system is very helpful. In this study, Alalbada-Erba multi-village Water distribution systemrnwas assessed as a case study.rnEPANET software was used as tool to model water distribution system. The modeling effortrnincluded both hydraulic and water quality modeling. Simulation results for maximum and minimumrnpressures were used as base to evaluate the hydraulic performance and simulation result forrnwater age and minimum residual chlorine were used as base to assess water qualityrntransformation in the distribution system.rnModeling results showed violation of maximum and minimum pressure requirements. Along withrnthis, water quality simulation results indicated water quality decline due to insufficient residualrnchlorine which is below WHO guideline. To retrieve the situation there is a need to intervene.rnModifications in operation and design will improve the current situation of the case study of waterrndistribution system.rnKeywords: - Water distribution system, modeling, Hydraulic performance, Water quality, Maximumrnpressure, Minimum pressure, Water age, Residual chlorine, Alalbada-Erba, Ethiopia.