Groundwater is a critical component of the United States’ water resources. Approximately 75 percent of community water systems in the United States rely on groundwater.
(1) Groundwater feeds streams and rivers, especially during periods of drought or low flow. The percentage of total irrigation withdrawals from groundwater increased from 23 percent in 1950 to 42 percent in 2000.
(2) Water supply managers in 36 states expected statewide, regional, or local freshwater shortages between 2003 and 2013 even under normal conditions.
(3) Given the importance of groundwater to the nation and the anticipated water shortages, the Association of American State Geologists, Ground Water Protection Council, Interstate Council on Water Policy, and NGWA undertook, in 2007, a national survey to identify what is being done to monitor groundwater quality and levels. Specifically, the survey sought information on statewide or regional, defined as multicounty, nontargeted, i.e., not at known contaminated sites, groundwater monitoring efforts. The following chart provides information on the survey and its results.