Tapping Into Our Ancient Supply

Deep below Costa Mesa lies an aquifer with amber tinted groundwater from remnants of the ancient redwood forests that once blanketed the Orange County coast more than 30,000 years ago. Over time, the ancient redwood trees were buried underground through mountain erosion carried by rivers, leaving behind organic compounds that give a distinct amber color to some of the water that Mesa Water District (Mesa Water®) treats and provides to customers. We lovingly call it “redwood tea.”

Mesa Water taps into this unique water source through two deep groundwater wells approximately 1,000 feet underground at the Mesa Water Reliability Facility (MWRF). The water is naturally soft and meets all drinking water quality standards. However, the MWRF uses a three-step treatment process—sand separators, cartridge filters and nanofiltration membranes—to remove the amber color. Once treated, this high-quality drinking water is delivered to Mesa Water customers. From pumping to treatment to delivery, the process takes about one hour—meaning many Mesa Water customers unknowingly enjoy this ancient treat every day!

This facility enables Mesa Water to achieve a 100% local water supply, serving all customers exclusively with groundwater and eliminating the need for higher-cost imported water—something all customers can be proud of. The “redwood tea” accounts for 15% of Mesa Water’s total supply, while the remaining 85% comes from shallower wells pumping replenished water from the principal aquifer in the Orange County Groundwater Basin. The deep aquifer is a reliable, long-term resource with hundreds of years of amber water.

To honor the ancient forest that helps supply water daily, a small redwood forest—routinely misted to simulate coastal fog—is located at the site of the MWRF and Mesa Water Education Center. It’s a living tribute that connects the community to the fascinating ancient origins of our water.