Water is a common resource for all living things which is fundamental to life. Adequate and quality water supply is an entry point to sustainable development. However, in most developing countries especially in sub-Saharan Africa, limited access associated with poor water supply, hygiene, and sanitation widening the poverty gap. The main objective of this study is identifying the problem of sustainability of rural water supply project of Mentawuha by using Statistical package for social science (SPSS) software from household survey using descriptive statistics. During this time, the less the respondents response indicates that the less the satisfaction level of the customer and this shows sustainability problems of the water scheme in the entire community. A mixed method research approach such as focus group discussion (FGDs) and different interviews was adopted whereby both qualitative and quantitative methods were employed in field data collection and analysis so as to find solutions to the existing sustainability problems in the study area. A total of 194 respondents were interviewed. The finding of the study demonstrated that there was no involvement of the beneficiaries in the decision of affordable and appropriate water supply technology selection. About 56% of the beneficiaries also not involved in the design stage of their water supply project. Water management committees were initially established, from them there was only one woman as a member. Four functional, five non-functional, and one totally abandoned public fountains were identified for the seek off to know rehabilitation and O&M need; construction quality problems had also been observed resulting from insufficient supervision works by key government officials. The study result also revealed that the operational sustainability of the rural water system in the study area was a serious problem. This was due to many factors including poor design and construction of water systems, lack of spare parts supply, lack of sense of ownership, and lack of training for water committees and operators at the community level accounts 71%, 79%, 45.4%, and 85% respectively, & inconvenient siting of water sources and unfair distribution of public fountains. Similarly, the result also showed that 77% of water sources are located on 15 minutes minimum and 45 minutes maximum distance from the customer; 60% of the people collect these amount of water from the existing source twice a day; 83% of beneficiaries need additional public fountains (PF), 70% of the entire communities were suffered by frequent queues. Enhancing community participation in every necessary decision and strengthening the technical and resource capacity of the town water supply institution are strongly recommended to sustain benefits of the community.