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Groundwater Issue: Groundwater Quality

California depends heavily on groundwater to meet its water supply needs, using more groundwater than any other state. During a typical year, approximately 40 percent of the state's total water supply comes from groundwater. During dry years, groundwater contributes up to 60 percent (or more) of the state's total supply, and serves as a critical buffer against the impacts of drought and climate change. Approximately 31 million Californians obtain their drinking water from a public water system that relies on groundwater for at least part of the drinking water supply. Additionally, two million Californians are served by private domestic wells or small water systems. However, because groundwater is not easily visible, it is often taken for granted, putting important drinking water and irrigation sources at risk of contamination (by both naturally-occurring and man-made contaminants).

The Water Boards protect, monitor, and restore groundwater quality through a number of programs and actions, including:

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