Mocho PFAS Treatment Plant: $54 Million to Protect Our Drinking Water

Zone 7's newly adopted Capital Improvement Plan includes the Mocho PFAS Treatment Plant at a total project budget of $54.4 million — an update from the earlier $35–51 million range. The facility is targeting a 2028 completion, and staff is pursuing a $25 million grant to offset costs.

This will be Zone 7's third PFAS treatment facility. The first two are already operational, treating contaminated groundwater and taking PFAS compounds out of the drinking water supply. Mocho extends that treatment network further.

The PFAS challenge in numbers

PFAS contamination has taken roughly 16 million gallons per day offline — about 40% of Zone 7's groundwater production capacity. That's water in the aquifer that can't be used until it's treated. Each new treatment facility brings some of that capacity back online.

The Mocho facility is being delivered using a Progressive Design-Build method with Kiewit/Hazen, and right-of-way negotiations with the City of Pleasanton are underway.

What I'm watching

The $25 million grant is a significant part of the funding strategy. If it comes through, it meaningfully changes the cost burden on ratepayers. If it doesn't, the board needs to be clear about where those dollars come from instead.

I'm also interested in the monitoring program downstream of all three facilities. As Zone 7 builds out its treatment network, the board's oversight role gets more important, not less. Are we catching what the models predict? Are we looking for what they might have missed? Those are the questions a board member with an engineering background should be asking.

PFAS Remediation is one of my three priorities for Zone 7, and the Mocho facility is evidence that the agency is investing at the scale this problem requires.