GWRS final expansion

The Groundwater Replenishment System Final Expansion Project (GWRSFEP) will increase GWRS treatment capacity to 130 MGD.

Groundwater Replenishment System Final Expansion Project Fact Sheet

In order to produce 130 MGD of purified water through the GWRS treatment facility, sufficient secondary effluent from the Orange County Sanitation District (OCSD) is required for source water. This secondary effluent source water for GWRS must be received from OCSD’s Treatment Plant 2, located in the city of Huntington Beach approximately 3.5 miles from the GWRS facility. In addition to expanding the GWRS treatment facility from 100 MGD to 130 MGD production capacity, conveyance facilities must be constructed to deliver the additional secondary effluent required for the GWRSFE Project. 

OCWD and OCSD commit to the following items, per the Second Amended and Restated Joint Exercise of Powers Agreement for the Development, Operation and Maintenance of the Groundwater Replenishment System and Green Acres Project, which was approved at the November 16, 2016 board meeting:

  • OCSD will continue to provide secondary effluent for GWRS free of charge as per the original agreement
  • OCSD will continue to allow OCWD to discharge brine free of charge
  • OCWD will pay for the total estimated cost of $282,248,496 for the GWRSFEP
  • OCSD will manage the Plant 2 Headworks Segregation Project and OCWD will reimburse OCSD for project costs
  • OCSD will lease ~10 acres of land to OCWD at $1 per year for the GWRSFEP
  • OCSD will allow OCWD to discharge North and South Basin extraction well flows to OCSD sewers
  • OCSD will complete and has completed projects to divert up to ~8 MGD from the SARI line of new wastewater for treatment at the GWRS facility
  • OCSD will provide conduit and power for communications/power to/from Plant 2 facilities. OCWD will reimburse OCSD for power costs.
  • OCWD secured a Water Infrastructure Finance and Innovation Act (WIFIA) loan from the U.S. EPA for $135 million

The table below lists all projects required for the GWRS Final Expansion and their estimated costs: 


Project Budget (30% Design)



CEQA for GWRSFE Projects




GWRSFE Design Consultant




GWRSFE Construction Management & Inspection


AWTF Expansion Construction


P2 Effluent Pump Station Construction


P2 Flow Equalization Tank Construction


P2 Pipeline Rehabilitation Construction


Engineering, Legal & Administration


GWRSFE Projects




GWRSFE Construction/Project Contingency


OCSD Project


OCSD Headworks Modification Project




Interest on Short-term Notes