The Groundwater Replenishment System is a groundwater management and water supply project that supplements existing water supplies by providing a new, reliable, high-quality source of water to recharge the Orange County Groundwater Basin and protect it from degradation due to seawater intrusion. What makes this project unique is that the source water is treated sewage. Orange County Water District and Orange County Sanitation District constructed this project to, also, help defer the need for the construction of another ocean outfall which would discharge wastewater.
Many water providers within the United States draw their water from surface water (rivers, lakes, etc.) or groundwater, treat it, and deliver it to their residents. If these bodies of water have upstream agencies discharging highly treated wastewater into them, then they are generally considered "unplanned" indirect potable reuse. The GWR System is a planned indirect potable reuse project which means all the purified water is recharged into the environment prior to being ultimately pumped back out and delivered to the residents of North and Central Orange County.
The water produced out of the GWR System is not similar to other recycled water. The water meets and exceeds all federal and California state drinking water standards. After treatment, it is the highest quality water of all sources in Orange County. Many other recycled water projects are used for non-potable applications like watering lawns, golf courses or greenbelts.
The GWR System facility purifies the highly treated sewer water by using a state-of-the-art, three-step process -- microfiltration, reverse osmosis and ultraviolet light with hydrogen peroxide. The water has already been treated twice by the Orange County Sanitation District.
OCWD experts have been testing the water purification technologies used in the GWR System for more than a decade. Constant water sampling and testing is part of the GWR System program to ensure water safety. Furthermore, the GWR System must be reviewed, approved and permitted by the California Department of Health Services and California Regional Water Quality Control Board to ensure public health, water quality and environmental compliance.