$33M Wastewater Facility Expansion Highlights Design-Build Delivery and Private Funding Partnership

TEMESCAL VALLEY, CA — The Elsinore Valley Municipal Water District (EVMWD) recently marked the completion of the upgraded and expanded Horsethief Canyon Water Reclamation Facility (HTCWRF) with a ribbon-cutting and valve-turning ceremony attended by more than 60 community members, regional partners, and developers.

The $33 million project increases the facility’s treatment capacity from 0.5 million gallons per day (MGD) to 0.8 MGD, providing wastewater service for approximately 1,200 homes in Temescal Valley.

As residential and commercial development continues across the region, the expanded facility helps ensure the district can meet rising wastewater demand while maintaining reliable service for customers.

Design-Build Delivery Marks a First for the District

The HTCWRF expansion represents several firsts for EVMWD, including the district’s first project delivered using the design-build delivery method.

The project team successfully completed construction despite supply chain disruptions that affected infrastructure projects across the industry during the COVID-era period.

In addition, the project highlights a strong public-private partnership model. Through collaboration with four regional developers, approximately 65% of the project’s cost was privately funded, reducing the financial impact on existing customers while accelerating the delivery of critical infrastructure.

“Projects like Horsethief Canyon demonstrate what is possible when innovation, stewardship, and collaboration come together,” said EVMWD General Manager Greg Thomas. “This facility reflects our commitment to responsible infrastructure planning—delivering lasting value for our customers and our community.”

Membrane Bioreactor Technology Improves Treatment Efficiency

The upgraded facility utilizes membrane bioreactor (MBR) treatment technology, which integrates membrane filtration with biological treatment processes to remove nutrients and improve effluent quality.

The technology allows the system to deliver high-quality treated water within a relatively compact footprint while helping reduce capital and energy costs.

The facility also incorporates automation features that allow operators to monitor and manage system performance remotely.

The treated effluent produced at the facility is suitable for non-potable reuse applications, including landscape irrigation and potential groundwater recharge—a valuable capability in water-scarce Southern California.

Program Management Supports Broader Water Reuse Expansion

EVMWD retained Carollo Engineers to provide program management and owner’s advisor services for the project, supporting the district throughout the design and construction phases as part of a broader water reclamation expansion program.

That program also includes upgrades to the district’s Regional Water Reclamation Facility, which will increase treatment capacity from 8 MGD to 12 MGD.

“What EVMWD accomplished here is remarkable—bringing together four private development partners, embracing a new project delivery model, and seeing it through despite significant supply chain challenges,” said Carollo Senior Project Manager and Vice President Jeff Weishaar. “The Horsethief Canyon WRF expansion is a testament to what thoughtful program management and strong partnerships can achieve, delivering resilient, future-ready water systems for the Temescal Valley community.”

Ceremony Recognizes Regional Collaboration

Representatives from federal, state, and local offices attended the ribbon-cutting ceremony and presented certificates recognizing the milestone project.

Attendees included representatives from the offices of Congressman Ken Calvert, Senator Kelly Seyarto, and Assemblywoman Sabrina Cervantes.

Following the ceremony, guests toured the upgraded facility to see how the improvements will support long-term water management and community growth in Temescal Valley.

To learn more about Carollo Engineers, visit www.carollo.com.