Provision of sustainable, efficient, reliable, and affordable water supply and sanitation services to the urban population as the Ethiopian water sector strategy is a major concern. However, in many towns like Addis Zemen, the hydraulic and physical performance of water distribution network is inadequate to meet the required consumers’ demands and Addis Zemen has been experiencing frequent water supply service interruption for days to a week. This study was conducted in Addis Zemen town, to evaluate hydraulic performance of existing water supply distribution system. The town water supply system has problems related to water supply coverage, water quantity, velocity, and system pressure. Beside to hydraulic performance analysis, water quality testing was done for different water quality parameters. The town water supply distribution system service coverage was also evaluated using the water demand and water production having 36.21 % coverage. Some points of the distribution system which has pressures greater than 70 m water column were observed at four junctions located around Michael sefer and two junctions were around Hospital due to low elevation. Some of the nodes have pressure below 15 m water column which were around Hanna Sefer and majority of the area has pressure within the optimum range during steady state analysis. During extended period simulation of peak hour consumption only 13.5 % of junctions have negative pressures, none of the junction has pressure above the limit and the remaining was within the limit. For low consumption time, none of the identified nodes have pressure below the limit and 34.7% of the nodes have pressure above the limit and 65.3 % were within the limit. The minimum velocity was occurred at the furthest junction from the reservoir and the maximum velocity was occurred near the reservoir. It is recommended that the water utility have to be developing a strategy based on the problems which were happened in order to improve the water supply hydraulic performance service level.