About GWRS

World's Largest Water Purification System for Potable Reuse

The Groundwater Replenishment System (GWRS) takes highly treated wastewater that would have previously been discharged into the Pacific Ocean and purifies it using a three-step advanced treatment process consisting of microfiltration, reverse osmosis and ultraviolet light with hydrogen peroxide. The process produces high-quality water that exceeds all state and federal drinking water standards.

Operational since January 2008, this state-of-the-art water purification project can produce up to 70 million gallons (265,000 cubic meters) of high-quality water every day. This is enough water to meet the needs of nearly 600,000 residents in north and central Orange County, California.

The design and construction of the GWRS was a project jointly-funded by the Orange County Water District and the Orange County Sanitation District. These two public agencies have worked together for more than 30 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.

Click here to read the GWRS Technical Brochure.