Purification 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 consisting of microfiltration, reverse osmosis, and ultraviolet light with hydrogen peroxide. The product water is near-distilled-quality.
The GWRS has a current production capacity of 130 million gallons (492,000 cubic meters; 400 acre-feet) of water per day and a total production of 44 billion gallons (167 million cubic meters; 134,000 acre-feet) per year. Approximately 30 million gallons (113,500 cubic meters) per day of GWRS water are pumped into injection wells to create a seawater intrusion barrier. Another 100 million gallons (378,500 cubic meters) are pumped daily to Orange County Water District’s percolation basins in Anaheim where the GWRS water naturally filters through sand and gravel to the deep aquifers of the groundwater basin to increase the local drinking water supply.
Explore the purification steps by clicking on the links below.

