Sustainable groundwater management is an important piece of the California Water Action Plan to put California on the path to sustainable management of all its water resources. Thirty-million Californians rely on groundwater for a portion of their drinking water. Groundwater provides about 40 percent of the state's total annual water supply, depending on wet or dry years, and serves as a critical buffer against drought and climate change. Some communities in California are 100 percent reliant upon groundwater for urban and agricultural use.
From 2005 to 2010, 16.5 million acre-feet of groundwater were used on average to meet urban, agricultural, and managed wetlands demands. Reliance on groundwater will continue to increase as the population grows, as limitations on surface water continue, and as potential impacts of climate change occur. Groundwater basins provide cost-effective local storage for water supplies that, if well managed, will make communities more resilient against climate change and future droughts.
Currently, where groundwater is managed, it is managed by local and regional agencies, some of which manage their resources sustainably. Other regions do not manage sustainably, resulting in problems such as groundwater overdraft, land subsidence, wells going dry, and deteriorated water quality.