In 2003 Aguaconsult was approached by the World Bank to carry out a research study and literature review to identify the key factors that may promote, or hinder, the sustainability of rural water supply projects following the period of construction. Sustainability is the overriding goal of RWSS projects. Yet although much attention is given to the design and implementation stages of projects, not much emphasis is given to the post-construction stage. Sustainability may be undermined, and systems may fail, due to lack of post-construction follow-up support. This might include no extension agents available to go to communities to help resolve disputes, no spare parts available, insufficient number of trained mechanics who can undertake more complicated repairs, or lack of refresher training for communities. During the course of the research study, Aguaconsult reviewed over 70 reports and publications, including both internal World Bank documents and those of other agencies. Including the Environmental Health Project, IRC International Water and Sanitation Centre, the Water, Engineering and Development Centre (WEDC), UNICEF, CARE International and WaterAid. The review concluded that communities cannot be expected to be able to manage their systems in the long-term without some level of assistance from external sources. Based on the wide ranging review of literature and project documentation it was possible to identify five main groups of factors which appear to affect post-project sustainability in a significant way, these are: technical; financial; community and social; institutional and policy; and environmental factors. Across these main groups there appears to be a hierarchy of factors, with the two most prominent being tariff collection to cover recurrent costs and the presence of some form of long-term external support.