Globally, 1 billion people are currently without access to improved water supply and 2.6 billion have no form of improved sanitation services (figures for 2004).  Most of these people live in Asia and Africa.  In Africa, for example, 2 out of 5 people lack an improved water supply.

Significant disparities exist between rural and urban services, which continue to contribute to the burden of life in rural areas.  People who live in the informal, overcrowded peri-urban settlements spawned by urbanization, also have especially low coverage.

Increasingly, surface and groundwater sources are being polluted by pesticides, and by industry and untreated household waste water.

The over-extraction of water for agriculture and manufacturing, which causes the water table to decline, is another bad practice, which threatens the sustainability of these resources in many parts of the world.

Planners of water development projects often do not consider the interdependence between water supply and health.  This can lead to negative consequences, such as the introduction of malaria or schistosomiasis into areas where it previously did not exist.