Zone 7 Highlights PFAS Treatment Protecting Tri-Valley Drinking Water During Groundwater Awareness Week

LIVERMORE, Calif. (March 10, 2026) – Zone 7 Water Agency (Zone 7) continues to invest in groundwater treatment infrastructure to ensure the Tri-Valley’s drinking water remains safe from per- and polyfluoroalkyl substances (PFAS), commonly known as “forever chemicals.” Zone 7 has two Ion Exchange (IX) PFAS treatment plants in operation and is currently planning a third treatment plant at the Mocho Wellfield in Pleasanton. The Livermore Valley Groundwater Basin plays a critical role in providing reliable water for the area, especially during droughts. Investments in PFAS treatment infrastructure will ensure the basin remains a safe and sustainable water source while supporting long-term reliability for the Tri-Valley.

“The groundwater basin is one of our most important water resources and provides us local control,” said Zone 7 Water Agency General Manager Valerie Pryor. “We store wet year State Water Project water in our local basin for use during dry years. Our investments in state-of-the-art Ion Exchange treatment at two existing and one future PFAS treatment plant allow us to continue sustainably managing the groundwater basin and delivering safe, high-quality water.”

Advancing PFAS Treatment to Protect Water Quality

PFAS are synthetic chemicals found in everyday products such as non-stick cookware, food packaging, and firefighting foams. These substances have been detected in air, soil, and water worldwide. Although water agencies do not produce PFAS, they are responsible for removing PFAS from contaminated water sources to ensure safe drinking water.

In 2018, Zone 7 initiated proactive monitoring for PFAS and, as a precaution, reduced production in wells where PFAS was detected while regulatory agencies worked to develop new standards for these contaminants of emerging concern. Since that time, Zone 7 has committed to meeting regulatory standards ahead of required compliance deadlines. Zone 7 was an early adopter of PFAS treatment:

• Stoneridge IX PFAS Treatment Plant – Opened in September 2023, this was the first plant of its kind in Northern California. Funded in part by a $16 million grant from the California Department of Water Resources, the plant set a new standard for PFAS removal.
• Chain of Lakes IX PFAS Treatment Plant – A larger-scale version of the Stoneridge plant, the Chain of Lakes treatment plant opened in March 2025.
• Upcoming Mocho Wellfield Treatment Plant – The third treatment plant is currently under design. This plant will further expand PFAS treatment locally, improve water quality, and restore groundwater pumping capacity when needed.

During Groundwater Awareness Week, March 8–14, Zone 7 is highlighting these efforts through an updated video explaining the Ion Exchange PFAS treatment process. Watch the video: Zone 7 Water Agency PFAS Ion Exchange Treatment.

Learn more about Zone 7’s efforts to address PFAS and explore Ion Exchange technology at zone7water.com/pfas.

Decades of Commitment to Groundwater Sustainability

The Livermore Valley Groundwater Basin serves as the Tri-Valley’s local “water savings account,” a vital resource that Zone 7 has managed sustainably since the 1960s. While the California State Legislature’s 2014 Sustainable Groundwater Management Act (SGMA) mandated statewide protections against overdraft, Zone 7 was already decades ahead of the curve in protecting this critical supply.

As the region’s designated Groundwater Sustainability Agency, Zone 7’s long-standing management plan was one of only nine accepted statewide by the Department of Water Resources as an Alternative Groundwater Sustainability Plan (AGSP)—a testament to the agency’s proactive stewardship. Today, groundwater provides approximately 10% of the Tri-Valley’s annual supply and acts as a critical lifeline during droughts. Zone 7 continues its leadership by actively replenishing the basin with imported water to ensure long-term reliability for the region.

Learn more at zone7water.com/groundwater.