Zone 7's $55 million plant to filter 'forever chemicals' from Mocho wells needs a new city land deal Tuesday

The water wholesaler that supplies Pleasanton is preparing to build a $55 million treatment plant to strip PFAS from groundwater pumped at its Mocho wellfield, and the City Council is set to sign off on the land rights it needs Tuesday.

Zone 7 Water Agency is putting the Mocho PFAS Treatment Plant on city-owned property at 2703 Santa Rita Road, at the southwest corner of Santa Rita Road and Stoneridge Drive, where it already operates wells. An amended easement agreement is on the consent calendar for the council's Nov. 17 meeting, which starts at 7 p.m.

Why the plant is being built

PFAS, short for per- and polyfluoroalkyl substances, are often called "forever chemicals" because they do not break down in the environment. They have turned up in groundwater across the country, including in Pleasanton, the city staff report says.

The plant is meant to make the wellfield's water meet today's drinking water rules and win back pumping capacity, the report says. It would also let Zone 7's existing Mocho Groundwater Demineralization Plant start running again to manage salt levels in the groundwater basin.

Zone 7 began conceptual design in April 2024, signed a progressive design-build contract in March 2026 and adopted its environmental finding in May 2026. Design is still under way, with construction expected to start in spring 2027.

Terms of the deal

The new agreement would replace easements the city granted Zone 7 in 2004 and 2013, for which the agency paid about $168,000. It covers three of the six city parcels at that corner.

Instead of paying cash for the expanded rights, Zone 7 would take a $92,000 credit against a $500,000 land allocation the two agencies set up in July 2025, when they settled litigation over the collection of water meter fees. That would leave $408,000 for future Zone 7 projects on city land. The $92,000 figure is based on appraisals each agency commissioned, according to the report.

Zone 7 would keep maintaining its wells and the new plant, plus the landscaping planted to screen the buildings and treat stormwater. The city would keep up the rest of the grounds. Zone 7 also agreed to rebuild up to 450 feet of the public trail on the site at no cost to the city.

Other easements on the land, one for Alameda County and one for a pipeline, stay in place.

City staff say there is no fiscal impact and that approving the deal lets the project move ahead without delay. Pleasanton buys treated water from Zone 7 to serve its own customers, which the report cites as the reason the city wants to cooperate.

Zone 7 held neighborhood meetings on the plant in September 2025 and September 2026. Items on the consent calendar are usually approved in one vote unless a council member pulls one for discussion.

Sources

pleasantonca.api.civicclerk.com

pleasantonca.api.civicclerk.com