The world’s largest water reuse project of its kind is now entering its final phase in SoCal’s Orange County. The Final Expansion of Orange County’s award-winning Groundwater Replenishment System (GWRS) is now underway with an estimated completion date of 2023. The joint project of the Orange County Water District (OCWD) and Orange County Sanitation District (OCSD) was celebrated last week with a groundbreaking ceremony.

The first of the three phases of the GWRS was brought online in 2008 and produced 70 million gallons of water a day (MGD) from wastewater. When the second GWRS phase was completed in 2015, it produced an additional 30 MGD for central and northwest Orange County residents. When the final expansion is completed, the GWRS will produce 130 MGD of advanced purified recycled water.

“Today marks an important milestone in Orange County’s water future,” said OCWD President Vicente Sarmiento. “Total production will be enough water for 1 million people when the expansion is completed. The GWRS is vital to combating climate change and sustaining Orange County’s water supplies and its thriving economy.”

Instead of discharging treated wastewater to the Pacific Ocean, OCSD and OCWD regard wastewater as a resource. The two agencies collaborate on the wastewater’s treatment and purification, and its pumping into recharge basins. The high quality purified water produced by the GWRS meets and exceeds state and federal drinking water standards.

“This project will allow the region to recycle 100% of OCSD’s reclaimable flows, which will be yet another first in the industry,” said OCSD Board Chairman David J. Shawver.

The GWRS project is able to produce purified recycled water at a lower cost than imported water. The Final Expansion has been made possible by these funding sources: $186 million through the Clean Water State Revolving Fund (SRF) Loan program;  $135 million from the Environmental Protection Agency’s WIFIA program; $3.6 million in Prop 1 grant funding managed by the California Department of Water Resources; and $1.1 million in grants from the U.S. Bureau of Reclamation’s WIIN program.

“The Orange County Water District’s advanced system expansion will benefit the local community, the economy and the environment,” said United States Environmental Protection Agency (EPA) Pacific Southwest Regional Administrator Mike Stoker. “We are honored to help fund this project and reduce borrowing costs through our WIFIA loan program.”

GWRS water currently accounts for one-third of the water that is put into the Orange County Groundwater Basin. Water from the GWRS supplements Orange County’s other drinking water supplies.