
Final expansion
The Groundwater Replenishment System Final Expansion (GWRSFE) project increased treatment capacity from 100 to 130 million gallons per day (MGD); enough water for 1 million people! In early 2023, a final expansion of the facility was completed, recycling 100% of local reclaimable wastewater flows, thereby maximizing water recycling efforts in the region.
In order to produce 130 MGD, additional treated wastewater was required from the Orange County Sanitation District’s (OC San) Treatment Plant 2, located in the city of Huntington Beach approximately 3.5 miles south of the GWRS. The GWRSFE project included expanding the Advanced Water Treatment Facility, constructing a new pump station and two flow equalization tanks, rehabilitating a pipeline, and modifying OC San’s headworks to be able to segregate reclaimable and non-reclaimable flows.
Project partners
- Operated and managed by: Orange County Water District
- Project partner: Orange County Sanitation District
- Project design: Black & Veatch
- Construction management: Butier and Carollo
- Construction: Shimmick
(February 2020-December 2021)
An investment in water supply reliability
- Provides a reliable supply of high-quality water, even during drought
- Reduces the need for imported water from northern California and the Colorado River
- Offers a more cost-effective and energy-efficient strategy than importing water from distant sources
- Improves water quality of the Orange County Groundwater Basin
- Creates a hydraulic barrier that prevents seawater intrusion into drinking water wells
- Replenishes groundwater supplies
- Reduces the volume of treated wastewater discharged into the ocean and puts it to beneficial use
- Serves as a global model for water reuse as the world’s largest recycling project of its kind
Project cost
The $284 million GWRSFE project was funded through a variety of different sources, including OCWD’s successful efforts to obtain a low interest rate loan of $135 million from the U.S. Environmental Protection Agency’s Water Infrastructure Finance & Innovation Act (WIFIA). The remaining $186 million is slated to be received from the State Revolving Fund (SRF) loan. Also, through the SRF loan application process the project was awarded a total of $5 million in grants.
Additional information
To learn more about the GWRS Final Expansion Project, please email us.

