Wayhill Reservoir Replacement – San Dimas

Golden State Water Company is committed to responsibly maintaining local water infrastructure so we can continue providing customers with safe, reliable water service they can depend on every day. To fulfill this commitment, we are making proactive investments to upgrade water supply and delivery facilities, creating sustainable, long-term value for the communities we serve. These forward-looking investments help prevent the costly and sometimes disruptive impacts of deferred maintenance or aging infrastructure, while ensuring a resilient water system for the future. 

An example of an investment in water infrastructure in your local area is the Wayhill Reservoirs Replacement Project in the San Dimas system. This project will remove and replace two aging 500,000-gallon concrete reservoirs that have reached the end of their service life. After decades of operation, the existing tanks no longer meet modern seismic, structural, or operational standards. The new welded-steel reservoirs are designed to provide improved durability, enhanced seismic performance, and long-term operational stability to better serve customers. 

In addition to replacing the reservoirs, the project will upgrade the site’s radio and telemetry equipment, strengthening Supervisory Control and Data Acquisition (SCADA) communication throughout the San Dimas system. Because the Wayhill Plant is located at a strategically high elevation with clear regional visibility, it serves as one of the most critical control points in the system. These communication upgrades enhance operational reliability, improve monitoring accuracy, and strengthen system responsiveness. 

Together, these improvements reduce the likelihood of service interruptions, enhance overall system resilience, and help ensure dependable water service for customers now and into the future. The project is expected to be completed in Fall 2026.