About GWRS
The world’s largest advanced water purification system for potable reuse
The GWRS is a joint project of the Orange County Water District (OCWD) and the Orange County Sanitation District (OC San). These two public agencies have worked together for more than 40 years. They are leading the way in water recycling and providing a locally-controlled, drought-proof and reliable supply of high-quality water in an environmentally sensitive and economical manner.
Operational since January 2008, the Groundwater Replenishment System is a state-of-the-art water purification project that can produce up to 130 million gallons (492,000 cubic meters) of high-quality water every day. This is enough water to meet the needs of nearly one million residents in north and central Orange County, California.
In commemoration of the GWRS 10th anniversary, OCWD and OC San set The Guinness World Records™ title for the most wastewater recycled to drinking water in 24 hours. By its 15th anniversary in 2023, the facility had produced more than 400 billion gallons of water and counting.
To learn more about the GWRS project, take a virtual tour or read the GWRS technical brochure (PDF).
Project benefits:
- Decreases Southern California’s dependency on imported water from the Sacramento-San Joaquin River Delta and the Colorado River
- Creates a locally-controlled, reliable supply of high-quality water that is drought-resilient
- Provides Orange County communities added assurance of sufficient water supplies to support economic vitality
- Produces high-quality water to replenish the groundwater basin
- Protects Orange County’s groundwater basin from seawater intrusion
- Serves as a blueprint for water agencies throughout the world to help solve their local water supply issues
- Protects the environment by reusing a precious resource
- Reduces the amount of wastewater discharged to the Pacific Ocean
- Uses less than half the energy required to transport water from northern to southern California
- Uses one-third the energy required to desalinate seawater
- Demonstrates a successful partnership between public agencies
- Created thousands of jobs from development, construction and operation of the GWRS
- Postpones, possibly indefinitely, the need for OC San to construct a second ocean outfall
- Improves groundwater quality by reducing the amount of dissolved solids (salt) in the groundwater basin
- Produces water at $750 per acre-feet – less than the cost of imported sources
- Produces water that meets or exceeds state and federal drinking water standards
