OC San puts $300m into aging wastewater asset renewal
Orange County Sanitation District, California · Meeting date: September 18, 2026 · Published: September 22, 2026
Orange County Sanitation District invested about $300 million in capital improvements during the past fiscal year, advancing more than 80 active projects. The programme targets assets whose estimated replacement value has risen to $17.7 billion, from about $9 billion when the district began the valuation effort.
Key points
- OC San reported approximately $300 million of capital investment in the past fiscal year across more than 80 active projects.
- The district estimates replacement of its wastewater infrastructure would cost about $17.7 billion, compared with roughly $9 billion when it began the effort.
- Major works include Plant 1 headworks rehabilitation and replacement of four primary clarifiers at Plant 2 that date to the early 1960s.
- Collection-system projects include the Cypress Trunk Sewer, Seal Beach Pump Station, Santa Ana trunk sewer, Bay Bridge Pump Station force mains and Taft sewer improvements.
Full report
Orange County Sanitation District (OC San) invested approximately $300 million in capital improvements in the past fiscal year, with more than 80 active projects intended to renew aging treatment and collection assets across central and northwest Orange County.
The investment programme was the central infrastructure message of the district’s September 18 State of OC San presentation. OC San said it estimates the replacement value of its wastewater infrastructure at approximately $17.7 billion, a figure that has risen from about $9 billion when it began the effort. The district linked the increase to the cost of materials and parts.
OC San operates more than 380 miles of sewer, 15 pump stations and two reclamation plants in Fountain Valley and Huntington Beach. The system treats an average of 185 million gallons of wastewater per day for approximately 2.6 million people, according to the presentation.
At Plant 1, the district is continuing rehabilitation of the headworks, which receives and lifts incoming wastewater. The scope includes the influent pump station, bar screens, grit treatment, electrical systems, standby power, odour control and underlying support facilities. OC San said this work is occurring while the plant remains in operation and while the district prepares for a Super El Niño.
At Plant 2, OC San is replacing four primary clarifiers dating back to the early 1960s. The district said the new units are intended to improve reliability and maintain treatment capacity for the community.
The capital programme also extends to the regional collection network. OC San cited work on the Cypress Trunk Sewer Project, replacement of the Seal Beach Pump Station at Westminster and Seal Beach Boulevard, and replacement of the Santa Ana trunk sewer, which it said dates to the early 1950s.
The district is also replacing force mains at the Bay Bridge Pump Station, where Pacific Coast Highway crosses the Back Bay. The mains have been buried in mud since the early 1960s, and OC San said their condition cannot be inspected because they are underwater.
In Orange, the Taft sewer project is progressing as a capacity upgrade. OC San also said it had exchanged lines with the City of Orange, converting a regional line to a local line and a local line to a regional line after changes to the 55 Freeway and infrastructure at Meats Avenue altered the original network context.
The presentation was an information item; no project-specific contract or funding approval was recorded.
This summary was generated by AI based on the source document and may contain errors.
Source: BOARD OF DIRECTORS, Orange County Sanitation District