Agriculture is a major user of ground and surface water in the United States, accounting for 80 percent of the Nation's consumptive water use and over 90 percent in many Western States. This ERS research program investigates water allocation, water conservation, and water management issues facing irrigated agriculture. The focus is on irrigated agriculture, but other sectors are examined for their competitive influence on water supplies and impacts of water reallocations among agricultural, environmental, and urban users.