Water is fundamental for life and health. The human right to water is indispensable for leading a healthy life with dignity. It is a pre-requisite to the realization of all other human rights. Realizing the critical importance of supplying potable water, national and county governments, local and international NGOs and the private sector invest millions of capital every year to tackle the problem through the implementation of water supply projects. However, constructing water supply systems alone would not eliminate all problems, especially in rural areas. Functionality, utilization by intended project participants, and resilience of water projects are important characteristics to be considered and integrated in order to achieve maximum benefits. There is a broad range of definitions of sustainability in rural water supply system projects. The majority of these definitions are similar in nature but have slight differences in emphasis. There also exist a number of definitions that are significantly different. How we define sustainability is important for selecting parameters, which are then important for measuring and understanding the determinant factors that affect the prospects of sustainability. That is to say that different groups of people, users of water, donors, national and county governments, local private sector companies, research institutions, etc. have different perceptions of sustainability based on the relative value attached to its achievements. Sustainability in the water supply sector is primarily associated with financial aspects of service delivery and the need to make projects self-sufficient, highlighting the need for users to contribute to cost-sharing. However, the above definition is problematic when considering the ultimate goals of providing rural water supply services. Improvements in health and the later positive impact on the broader well-being of rural populations can be the perceived benefits of water projects for many local, national, and international agencies. Therefore, the logical definition of sustainability from the perspective of these institutions may be one that includes sustained health and other positive impacts. Whereas, for many rural communities, the perceived benefit of a project may simply be continued access of water nearby; which is closer to the definition that simply describes sustainability as whether or not water continues to flow over time. A number of studies have identified various determinants of sustainability of rural water supply system. However, some of the most common determinant factors are; technical factors including design, performance and maintenance issues, Community and social factors including willingness to support projects thus creating long-term social behavior changes, Institutional factors including policy and external follow-up support, Environmental factors including the sustainability of the water source, Financial factors including the ability to cover recurrent costs. Given this view it is fair to say that perhaps many of the definitions of sustainability may not yet have caught up with current thinking and that, at least for the community management model, definitions should be reconsidered and modified to account for this potential contradiction. Therefore, classifying a community-managed rural water supply system as sustainable should not necessarily preclude the community from having access to continuous, external back-up support of some kind. Blog By: Caleb Mosoti : Water Sanitation Hygiene and Promotion Manager Caritas Isiolo. : Caleb Holds a degree in Civil engineering from Jomo Kenyatta University of Agriculture and Technology and vast experience in Humanitarian response. Reach him on or