At its April 21 meeting, the Pleasanton City Council unanimously voted to move forward with implementing the Joint Groundwater Supply Project in partnership with Zone 7 Water Agency (Zone 7), a major step toward restoring a reliable, long-term local water supply.
Historically, local groundwater has supplied about 20 to 30 percent of Pleasanton’s annual water demand, or about 3,500 acre-feet per year. In 2022, the City’s three local groundwater wells were taken offline due to PFAS detections, forcing the City to rely solely on purchasing wholesale water from Zone 7. This shift increased water supply and distribution costs, contributed to higher water rates, and raised concerns about long-term reliability and drought resilience.
Since then, the City has been evaluating long-term water supply options. In October 2022, the City launched a Water Supply Alternatives Study to assess multiple strategies, including rehabilitating the City’s existing wells with PFAS treatment, developing new groundwater wells, and continuing to rely entirely on purchased water from Zone 7. The study identified the development of new groundwater wells in Pleasanton as the most economical and reliable long-term path forward.
As part of that effort, the City and Zone 7 completed a joint feasibility study in December 2025 to evaluate new groundwater wells in the Bernal Subbasin. The study found that a joint groundwater project is viable and identified Tennis Park and Hansen Park as feasible locations for new wells that can provide a sufficient water supply while maintaining water quality and long-term groundwater sustainability.
Throughout this process, the City has sought to carefully evaluate all available options and the associated risks, with a focus on long-term sustainability and rate stability. Overall, the development of new groundwater wells would further diversify local water resources and strengthen water reliability across the Tri-Valley.
Most recently, the City also conducted a cost-benefit analysis comparing multiple alternatives for new groundwater wells and determined that the joint project with Zone 7 is the most cost-effective and advantageous path forward.
The analysis found that annualized costs for the joint project were lower than those of the alternatives and that capital costs were consistent with the assumptions in the City’s 2025 Water Rate Study. At approximately $27 million, the joint project is significantly less than the estimated $65 million it would cost, in today’s dollars, to rehabilitate the City’s existing wells and construct PFAS treatment facilities. In addition, the project builds on the City’s longstanding partnership with Zone 7 and reflects both agencies’ shared commitment to delivering reliable, high-quality water service across the region
“This is an important milestone in securing Pleasanton’s water future,” said Alexa Jeffress, Assistant City Manager. “We look forward to working with Zone 7 to finalize an agreement that meets the needs of both agencies and move this project into design and construction.”
The next step will be to finalize a draft agreement with Zone 7 regarding the design, construction, and operation of the new facilities, and to bring it back to the City Council for further consideration and approval.
For more information about Pleasanton’s water system and ongoing water planning efforts, visit www.PleasantonWater.com. Follow us on Facebook and Instagram @CityofPleasantonCA.