Finding the Leak: A Campus-Wide Collaboration

In Spring 2025, a quiet but concerning trend caught the attention of the UC Davis Facilities Management central plant team: the campus chilled water system required frequent “top-offs.” In simple terms, more water than usual was being added to the system to keep it running, indicating that a significant leak was occurring somewhere underground or going unnoticed in a building.

No one knew where.

A System That Serves the Entire Campus

The chilled water system is one of the campus’s most critical infrastructure networks. It circulates cooled water through a network of 28 miles of underground pipes to regulate temperatures in over 120 buildings across campus. Maintaining that system isn’t just about comfort; it’s essential for labs, research facilities, and specialized equipment that depend on precise environmental conditions year-round.

Beyond the physical loss of water, the leak created a second problem: energy waste. Every gallon of replacement water had to be cooled again at the central plant. And because corrosion inhibitors and biocides are added to the system to protect pipes and prevent biological growth, constant dilution makes it harder to maintain proper chemical concentrations. Over time, that instability can impact system reliability and longevity. In short, the leak was wasting water and energy, increasing operational costs, and threatening the long-term health of a critical campus utility.

A Cross-Disciplinary Effort

A working group formed in Spring 2025, bringing together experts from Building Management Systems (BMS) and Utilities & Engineering. Their mission was clear: identify the location of the leak and repair it. Initial investigations in Summer and Fall 2025 included wastewater sampling across different portions of campus to look for traces of chilled water. The idea was innovative. If chilled water showed up in specific wastewater streams, it could narrow the search area. However, the nature of the leak meant it wasn’t clearly detectable through the sampled areas, leaving the team without a clear answer.

An Ambitious Shutdown

With sampling unable to pinpoint the issue, the team proposed something that had never been done before on campus: a full shutdown of entire portions of the chilled water system for a day. The work was carefully scheduled in Winter 2025, when air conditioning demand was lowest. Even then, more than a dozen buildings required chilled water 24/7 due to research operations. Teams collaborated closely with building occupants to develop thoughtful temporary solutions, ensuring critical systems remained protected.

During the shutdown, crews methodically isolated portions of campus. By restoring sections incrementally and observing system behavior, they were able to narrow the leak location step by step until it was precisely identified. This long and iterative process took patience and determination from all involved. The source was a more than 50-year-old four-inch pipe serving the Medical Sciences C building. The leak was located under a sidewalk, but the sidewalk had been installed with “subdrains,” which carried the chilled water away into a French drain that allowed it to remain undetected for so long. Utilities crews quickly excavated the area and completed the repair in January 2026.

Strategic Impact

Repairing the leak delivered immediate and long-term benefits. Eliminating the continuous loss of chilled water conserved significant amounts of water and reduced unnecessary energy consumption at the central plant. Stabilizing chemical concentrations within the system improved infrastructure protection, reducing corrosion risks and supporting long-term pipe integrity. Together, these improvements strengthened system resilience and reliability, ensuring Facilities can continue to deliver dependable service to research labs and campus partners—especially during peak summer demand.

What Made This Project Stand Out

This project was notable not only for its technical complexity but also for its collaboration. A diverse group of professionals from multiple disciplines worked together to solve a problem that required creativity, persistence, and trust. Campus customers were incredibly flexible and supportive during shutdown planning and execution, helping coordinate building-specific solutions that allowed the work to proceed safely.

The ambitious isolation strategy ultimately became a model for future large-scale system investigations, giving the team a clearer roadmap for managing complex utility challenges moving forward.

What’s Next

While this major leak has been repaired, the team believes there may be additional, smaller issues within the system. Lessons learned from this investigation are already being applied to future diagnostic efforts. In addition, Facilities Management is exploring automatic leak detection technologies that could help identify anomalies earlier and reduce system risk in the future.

This project underscores how thoughtful infrastructure management directly supports campus sustainability, safety, and research excellence. Sometimes the most impactful work happens underground, quietly protecting the systems that keep the university running every day.