City of Modesto begins construction to connect 600 people to safe drinking water

MODESTO – The Central Valley Regional Water Quality Control Board yesterday approved the Modesto Management Zone Order, advancing implementation of the Central Valley Salinity Alternatives for Long-Term Sustainability (CV-SALTS) Nitrate Control Program in one of the region's highest-priority groundwater areas.

Since the program launched in 2021, over 2,200 households have received free replacement drinking water and more than 5 million gallons of safe drinking water have been distributed.

The order builds on that progress by establishing a long-term framework to protect drinking water supplies, reduce nitrate pollution and restore groundwater quality within Modesto and surrounding area covered by the Modesto Management Zone.

“Since the inception of the Nitrate Control Program in 2018, farmers, municipalities and businesses in the valley have been providing residents with free replacement drinking water when testing shows that their wells have been impacted with nitrates,” said Patrick Pulupa, executive officer of the Central Valley Water Board. “This order begins the next phase of the program, where permittees in the Modesto Management Zone will work even harder to reduce nitrate pollution and restore groundwater. This action is a major step toward improving water quality for thousands of Central Valley families.”

The program requires dischargers in high-risk areas to provide replacement drinking water, reduce nitrate loading and, where feasible, restore groundwater quality. The regional board has previously expanded the program across Priority 1 and Priority 2 groundwater basins, enabling widespread domestic well testing and replacement drinking water programs throughout the Central Valley.

The order approves the area's Management Zone Implementation Plan and establishes enforceable requirements for drinking water protection, nitrate reduction and long-term groundwater restoration. The order also grants participating dischargers time-limited nitrate exceptions tied to specific milestones, monitoring requirements and performance standards.

Key requirements include:

• A complete inventory of domestic drinking water wells within one year.
• Well testing offered to all domestic drinking water wells within five years.
• At least one public water filling station completed within one year.
• Long-term drinking water solutions offered to 20% of affected wells by Year 6 and 100% by Year 18.
• Annual progress reports and regular public review of program performance.

The order also includes public engagement requirements, including community meetings and ongoing outreach to residents and stakeholders.

The regional board retains authority to revise milestones, adjust timelines or revoke nitrate exceptions if performance requirements are not met.

Nitrate contamination in drinking water can pose serious health risks, particularly for infants and pregnant women. California's drinking water standard for nitrate is 10 milligrams per liter (mg/L), also referred to as 10 parts per million nitrate-nitrogen.

For more information about the CV-SALTS Nitrate Control Program, visit www.cvsalinity.org.  An interactive map showing the management zones can be found at: Find Your Management Zone - CV SALTS.

The Central Valley Regional Water Quality Control Board protects water quality and beneficial uses of surface water and groundwater across approximately 60,000 square miles of California. The region encompasses the state's largest contiguous groundwater basin and includes all or portions of 38 counties.