Zone 7 Water Agency serves the Tri-Valley


As the Tri-Valley region’s water wholesaler, we work with our water retailers to ensure that over a quarter of a million people are served safe and reliable drinking water. Zone 7 also provides flood protection for all of eastern Alameda County. We work collaboratively with policymakers and legislators to make sure we can continue providing exceptional service delivery to our community. For the most current news from Zone 7, visit

What Puts Our Water Supply at Risk?

The Tri-Valley is heavily reliant on imported water through California’s State Water Project, which helps to buffer the impacts of the historic over-pumping of the local groundwater basin from the early to mid-1900s. Along with importing approximately 70% of the water supply, managing the groundwater storage and water quality increases the cost of delivering our water and leaves us vulnerable to long-term reliability concerns.

Challenges that put our communities at risk for water shortages are:

Per- and polyfluoroalkyl substances (PFAS) are emerging concerns as our Agency relies on groundwater during drought periods. Three projects to alleviate PFAS contamination in groundwater at local wells are in the works and one has been constructed. The Stoneridge Well PFAS Treatment Facility was producing treated water in September 2023, with final site completion anticipated in early 2024. The Chain of Lakes PFAS Treatment Facility is currently under construction and anticipated to be complete in Summer 2024. A third project, the Mocho Wellfield PFAS Treatment Facility, is in the planning phase and is proposed for completion in 2026.  This treatment is expensive and ongoing investment in our treatment system is needed to address this important concern. For more information on PFAS and what Zone 7 is doing to address this concern, visit

Aging Infrastructure:
The State Water Project infrastructure, which we depend on for most of our water supply, is aging and at risk of failure. Investing in this infrastructure will ensure it continues delivering water to our community. The State Water Project estimates that contractors, such as Zone 7, will have to share in the costs to update these facilities. 

Climate Change:
The changing climate is impacting California’s water resources, causing prolonged droughts or extreme weather patterns, such as atmospheric weather patterns.

DWR Low Water Levels Lake Oroville

How does flooding impact our community?

For more information on Zone 7’s Flood Protection activities, visit

Climate Change: 
Atmospheric Rivers bring much-needed rainfall, but also can cause significant channel damage and flooding.

Flood Channel Maintenance:
Ongoing maintenance of our 37 miles of flood channels is vital to our community. Ensuring a clear path for stormwater during rainy seasons protects our homes and business from flooding.

Damage to Infrastructure: 
In 2017, and in the most recent storms in 2022 and 2023, storm damage resulted in millions of dollars in damage. The Zone 7 team requires multiple years to repair the hundreds of bank slides that occur during heavy rains. Funding for emergency repairs is dependent on many factors and requires diligent staff effort to identify and secure grants to supplement existing revenues.

Keeping Our Community’s Water and Flood Protection Affordable and Reliable

Zone 7 strives to provide Alameda County with reliable, high-quality water and effective flood protection. We cannot meet this goal without local, regional, state, and Federal collaboration. 

Examples of how policymakers can help:

  • Provide legislative and funding support for our long-term water supply and storage projects currently underway, including the Sites Reservoir project, Los Vaqueros Reservoir Expansion Project, and Delta Conveyance project. Other water supplies under consideration include the Bay Area Regional Desalination project and the Tri-Valley Potable Reuse project.
  • Support and funding for the construction and maintenance of PFAS treatment projects to keep water safe and critical production wells online. Zone 7 needs legislative partners to help identify Federal and State funding or other legislative solutions to support projects critical to water reliability and flood protection for the Tri-Valley.
  • Acknowledge that water agencies are a part of the solution in treating contamination in drinking water by exempting agencies from liability arising out of any changes to the Comprehensive Environmental Response, Compensation, and Liability Act (“CERCLA”).
  • Funding to support the  flood programs such as the U.S. Army Corps of Engineers PL-84-99 program, which is critical to continued assistance to local agencies.

Zone 7 Water Legislative Framework

On January 17, 2024, the Zone 7 Board of Directors adopted a revised legislative framework to help guide our work in alignment of our Strategic Plan, and provide a roadmap to our legislative committee and staff. The latest framework can be found here: