Development patterns, increasing population pressure, and the demand for better livelihoods in many parts of the globe all contribute to a steadily deepening global water crisis. Development redirects, consumes, and pollutes water. It also causes changes in the state of natural water reservoirs, directly by draining aquifers and indirectly by melting glaciers and the polar ice caps. Maintaining a sustainable relationship between water and development requires that current needs be balanced against the needs of future generations. The development community has transformed and broadened its approach to water since the 1980s. As stresses on the quality and availability of water have increased, donors have begun to move toward more comprehensive approaches that seek to integrate water into development in other sectors. This evaluation examines the full scope of the World Bank’s lending and grant support for water activities. More than 30 background papers prepared for the evaluation have analyzed Bank lending by thematic area and by activity type. IDA and IBRD (the Bank) have supported countries in many water-related sectors. The evaluation, by definition, is retrospective, but it identifies changes that will be necessary going forward, including those related to strengthening institutions and increasing financial sustainability. Lessons and results from nearly 2,000 loans and credits, and work with 142 countries are identified.