Rural water supply facilities (RWSFs) serve approximately 20 million people in Kenya, which accounts for 40% of the population. Many RWSFs are managed by the community under a community-based management system. The low functionality of RWSFs because of mismanagement of the community is often argued. However, the low capacity of community management is not necessarily attributed to the low functionality. Based on the current status of RWSFs, which were constructed with the support of the Japan Official Development Assistant, we found that only two out of 18 nonfunctional facilities were due to the issue of community management. Furthermore, a total of 24 out of 62 hand pumps were upgraded to motorized schemes, thanks to the efforts of local county governments. Through literature review and detailed study of existing RWSFs, we suggest five factors for sustainability: i) salinity of groundwater, ii) practice of fee collection and type of facility, iii) external support, iv) adoption of operation and maintenance system according to socioeconomic condition, and v) improving the capacity of community organizations and ensuring transparency on revenue. In addition to the five factors, we presented specific features with respect to the five factors in the context of Kenya. The motorized schemes of the target facilities indicate a higher functionality than that of hand pumps. This is because the motorized scheme, especially the piped schemes, has the potential for the practice of fee collection thanks to its contribution to better accessibility, resulting in better sustainability. Given the poverty and nature of RWSFs, achieving full cost recovery of RWSFs is challenging. However, we strongly suggest that the water fee of RWSFs must cover daily operational costs, and the cost of major repair as much as possible.