Communities located in north and central Orange County have an underground aquifer -- the Orange County Groundwater Basin (Basin) -- to capture and store water. This well-managed 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.

Although underground basins are geological and do not respect political boundaries, the 270-square-mile portion of the Basin inside Orange County is operated by the Orange County Water District (OCWD) in cooperation with the Producers (19 cities and water districts) that pump groundwater to serve agriculture, businesses, and more than 2.5 million residents in north and central Orange County. As part of its historically wise use and management, OCWD has worked in partnership with the Orange County Sanitation District to create and expand the Groundwater Replenishment System that replenishes the Basin with recycled water treated to potable water standards from its service area.

water map

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.

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