Water is essential for economic growth, human health, and the environment. Pressures on water resources are exerted by overexploitation or inefficient use, as well as by degradation of water quality. Governments around the world face significant challenges in managing their water resources effectively. The problems are multiple and complex: billions of people are still without access to safe water and adequate sanitation; and major investment is required to maintain and improve water infrastructure. In some regions competition for water is increasing among the different users and water availability is a constraint on economic development.