Final expansion

The Groundwater Replenishment System Final Expansion (GWRSFE) project will increase the system treatment capacity from 100 to 130 million gallons per day (MGD).

Groundwater Replenishment System Final Expansion Project Fact Sheet

In order to produce 130 MGD of purified water through the GWRS, additional secondary effluent from the Orange County Sanitation District (OCSD) is required for source water. This additional secondary effluent source water must be received from OCSD’s Treatment Plant Number 2 (OCSD P2) which is located in the city of Huntington Beach approximately 3.5 miles south of the GWRS facility.  The GWRSFE project will include expanding the GWRS treatment facilities, constructing new conveyance facilities at OCSD P2, and rehabilitating an existing pipeline between OCSD P2 and the GWRS.

OCWD and OCSD approved 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 in November 2016. This agreement details the continued partnership responsibilities between OCWD and OCSD to complete the GWRS Final Expansion project.

For the project,

  • OCSD/OCWD has received a USBR Title XVI grant for the P2 Headworks Modification Project
  • In August 2018, OCWD Board of Directors executed a loan agreement with the US EPA for a low interest rate WIFIA loan in the amount of $135 million
  • OCWD has applied for Prop 1 grants from the IRWM grant program managed by the California Department of Water Resources
  • OCWD’s application for a State Revolving Fund (SRF) Loan through the State Water Resources Control Board has been deemed complete with an intent for the remaining project costs to be funded through this SRF loan.

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


Projected Budget



Studies/CEQA for GWRSFE Projects


Design Engineering Services


B&V Agreement including Amendments 1-4


Construction Management/Inspection


Butier/Carollo CM Agreement


Specialty/Materials Construction Inspection


Total CM and Inspection 




Contract 1 - AWTF Expansion Construction


Contract 1 - P2 Effluent Pump Station Construction


Contract 1 - P2 Flow Equalization Tank Construction


Contract 2 - P2 Pipeline Rehabilitation Construction


Total Construction Phase


Engineering Support, Legal & Administration 


SPI Agreement (Process Support)


Legal/Admin/Survey/Public Outreach Support


Total ELA




Construction Contingency


OCSD Headworks Modification Project




The GWRSFE project construction contract was awarded
at the September 4, 2019 Board of Directors Meeting. Construction began in November 2019 and will be complete in 2023.  Please contact Sandy Scott-Roberts if you have any questions or for additional information on the GWRSFE project.