ORANGE COUNTY GROUNDWATER BASIN

Communities located in north and central Orange County, including Mesa Water’s service area, are fortunate to have an underground aquifer - the Orange County Groundwater Basin (Basin) - to capture and store water. This water resource reduces Orange County’s dependence on more costly imported water from Northern California and the Colorado River, helping to keep water rates reasonable and ensuring local water supply reliability. The vast, 270-square-mile Basin is operated by Orange County Water District (OCWD), with the cooperation of the 19 cities and water districts, also known as the Producers, that pump groundwater from the Basin, to serve water to businesses and more than 2.5 million residents in north and central Orange County.  

OCWD provides 77% of the water served by Mesa Water – and the Mesa Water Reliability Facility provides the rest and can serve up to 50% of our community’s water needs if needed.

Since 1933, when the California State Legislature formed it, OCWD has been entrusted to guard the region's groundwater basin. OCWD manages and replenishes the basin, ensures water reliability and quality, prevents seawater intrusion, and protects Orange County's rights to Santa Ana River water.

Additionally, OCWD partners with the Orange County Sanitation District on the Groundwater Replenishment System that replenishes the Basin with highly-treated wastewater from its service area.

Mesa Water is committed to being a good steward of the Orange County Groundwater Basin and protecting its management. Learn more here.