Groundwater accounts for about 5 percent of the San Diego region’s water supply portfolio. It’s a small but growing and important resource, especially in places like the South Bay where the aquifers are relatively large.


The San Diego region’s groundwater is limited by several factors, including little groundwater recharge due to sparse rainfall. Although groundwater supplies are much less plentiful here than elsewhere in California, pockets of undeveloped brackish – or saline – groundwater could help meet more of the region’s future water demand.

While the Water Authority does not hold groundwater rights, it does provide financial and technical assistance to member agencies that are evaluating, planning and implementing groundwater recovery projects. In fact, several local water agencies have identified potential projects that could nearly double groundwater production in coming years by treating brackish groundwater to potable standards.

Sustainable Groundwater Management Act

In 2014, the California Legislature passed the Sustainable Groundwater Management Act (SGMA), making California the last state in the West to regulate groundwater. The process started with the Department of Water Resources classifying California’s 515 groundwater basins into four categories: high, medium, low, or very low. SGMA requires medium- and high-priority basins to develop groundwater sustainability agencies, develop groundwater sustainability plans and manage groundwater for long-term sustainability. Click here for more information about California SGMA.

The three SGMA-mandated basins in San Diego County are San Luis Rey Valley (medium priority), San Pasqual Valley (medium priority), and Borrego Valley (high priority). Click here for more information about San Diego SGMA.