The study focused on the assessment of water supply service provision limitations and its effectsrnin Masha town of south western Ethiopia. In the town, piped water service unavailability andrnquality was common issues to water users. On the other hand, topography of Masha town isrnundulating and equity in water service was under question. The study mainly aimed to assess thernexisting situation of the service, water sources for domestic activities, perception for the lowqualityrnrnpiped water and evaluating the service based on key physiochemical parameters andrnpressure. Existing water service were assessed based on site visits checklists, questionnaires andrninterviews of service providers. Out of total 4586 households in the town sample size of 100rnwere selected using standard procedures. Water quality sample was tested at different locationsrnin water supply system from source to point of supply using photometer, pocket colorimeter andrnPH meter apparatuses. Pressure of water service in the town were modeled using Water GEMsrnwhich was calibrated by actual measured pressure data. The study indicates that existingrnestimated demand of water for the town was 1477.31 mrn/day and designed capacity of existingrnwater supply system was 803.52 mrn3rn/day (54.39 % of current demand). Existing water productionrnamount was 33% of total production capacity and only 15.56% of total capacity were pumped torncentral reservoir. The cause for limited service capacity were found to be inefficient institutiona lrncapacity of service providers that leads to inappropriate operation and maintenance. Thernsocioeconomic analysis result depicted that all of households were dissatisfied with piped waterrnservice and its primary common cause were service unavailability (66 %) and degraded waterrnquality (33%). Water quality test result of the town showed that average concentration of Fe, Mn,rnPH and Free Cl2 were 1.430 mg/l, 0.005mg/l, 7.48 and zero respectively. Iron (Fe) was found farrnhigh above recommended value of 0.3 mg/l that makes the piped water to be in a very high-riskrncategory. As the model result showed that pipe water pressure was very low in some areas of therntown like center of the town where high vertical development was undergoing. Therefore, waterrnsupply service of the town has limitations on water quality, availability and equity in the townrndue to inefficiency of treatment plant and institutional capacity of service providers. The servicernstates has high risk for piped water users and needs water safety planning, household water levelrntreatment practice, upgrading treatment plants and zonal supply for low pressure areas.