New water you can count on
The Groundwater Replenishment System (GWRS) is the world’s largest water purification system for indirect potable reuse. The system, which is a joint partnership between the Orange County Water District (OCWD) and the Orange County Sanitation District (OC San), 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 meets all state and federal drinking water standards.
Increasing Local Water Supplies
130 million
1 million
100%
35%
demands met
$900 million
expand water reuse
The process
After wastewater is treated at the Orange County Sanitation District, it flows to the GWRS where it undergoes a state-of-the-art purification process.
Frequently asked questions
You have questions? We have answers. Explore some of the GWRS’ most frequently asked questions.
Technical brochure
View/download the GWRS technical brochure for in-depth information on the process and facility.
