A $33 million expansion of the Horsethief Canyon Water Reclamation Facility in Temescal Valley, California, has been completed, marking a milestone for regional wastewater infrastructure and public-private collaboration.
The project, delivered for Elsinore Valley Municipal Water District (EVMWD), was formally inaugurated during a ribbon-cutting and valve-turning ceremony attended by more than 60 community members, partners and developers. The upgrade increases the facility’s treatment capacity from 0.5 million gallons per day (MGD) to 0.8 MGD, enabling wastewater service for around 1,200 homes as development continues to grow in the area.
According to the district, the project supports long-term planning in Temescal Valley by ensuring wastewater services can keep pace with residential and commercial expansion while maintaining reliable operations.
The Horsethief Canyon project also marks the district’s first use of a design-build delivery approach. Despite supply chain disruptions during the COVID-19 period, the project was successfully completed through collaboration with multiple stakeholders. Four regional developers collaborated in this public-private partnership, with 65% of the total project cost privately funded, reducing the financial burden on existing ratepayers.
“Projects like Horsethief Canyon demonstrate what is possible when innovation, stewardship, and collaboration come together,” said Greg Thomas, General Manager of EVMWD. “This facility reflects our commitment to responsible infrastructure planning — delivering lasting value for our customers and our community.”
The upgraded facility uses membrane bioreactor (MBR) technology, which combines biological treatment with membrane filtration to remove nutrients and produce high-quality effluent. The system is designed to operate within a compact footprint while reducing capital and energy requirements. Automation features also allow operators to monitor and manage processes remotely.
The treated water produced at the facility can be used for non-potable purposes such as landscape irrigation or groundwater recharge, supporting water reuse efforts in drought-prone Southern California.
Carollo Engineers served as program manager and owner’s advisor for the project.
