REDWOOD CITY, Calif. — The San Mateo County Board of Supervisors on Oct. 20 approved a new Farm Labor Housing Water System Inspection Program that establishes regular water testing and inspections for small water systems serving farmworker housing.

The new program will cover 32 water systems serving 49 farmworker housing units in unincorporated San Mateo County, and it addresses a gap in the existing legal framework for drinking water systems. 

Until now, small water systems serving farmworker housing with four or fewer service connections generally were not subject to routine regulatory oversight. Rather,  enforcement was largely limited to responding to reports of conditions that posed an imminent health hazard. 

The program is designed to strengthen public health protections for agricultural workers and their families while helping property owners meet the new requirements. It is part of an update to the County’s Domestic Water Systems Ordinance that takes effect Nov. 19, 2026.

Building on the County's farmworker housing efforts

The program builds on the County's response to the Jan. 23, 2023, mass shooting at two Coastside farms, which killed seven farmworkers and critically injured another. The tragedy exposed unsafe living conditions in employer-provided housing. 

At the request of District 3 Supervisor Ray Mueller and other County and local leaders, several County departments formed the Farmworker Housing Compliance Task Force to inspect farmworker housing on agricultural and ranch land in unincorporated San Mateo County.

As part of that effort, the Task Force tested 38 water systems serving farmworker housing that were not already subject to regular state monitoring. Twenty-one systems, or 55 percent, tested positive for coliform and/or E. coli bacteria. Corrective actions were taken at all affected systems, and follow-up testing confirmed safe drinking water.

Because the findings showed the need for ongoing oversight rather than one-time fixes, the Task Force’s February 2025 final report recommended a local ordinance requiring permits and regular water testing for these small systems. 

“After the tragedy in January 2023, we made a promise that every farmworker on the Coastside would live in a safe and healthy home. The Task Force showed us that unsafe drinking water was the most common problem these families faced,” said Supervisor Mueller, whose district includes the San Mateo County coast. 

“This ordinance turns that finding into lasting protection, with regular testing for families and real support for the farmers who house them. It is the product of years of collaboration among the County, Coastside community organizations, farmers, and advocates, and I am grateful to everyone who helped us get it right,” Mueller said.

Regular testing and inspections

Under the new program, operators of farm labor housing water systems must test for coliform and E. coli bacteria every three months, meet standards for water quality, quantity and pressure, and allow regular County inspections.

Owners and operators are responsible for correcting imminent health hazards in their water systems, including hazards affecting tenants.

San Mateo County Environmental Health Services developed the program with input from agricultural operators and community representatives, including the Pescadero Municipal Advisory Council, the San Mateo County Farm Bureau and the San Mateo County Agricultural Advisory Committee. That feedback helped shape the inspection and testing requirements to reduce costs while maintaining regular monitoring. 

“Safe drinking water depends on regular testing and on owners who know exactly what is expected of them,” said Charles Ice, director of Environmental Health Services. “We built this program with input from the farmers, ranchers, and Coastside community members who will live with it. The result is a program that puts more testing where it matters most. Our staff will work with each operator, step by step, to bring their water systems into compliance.”

County assistance with permit fees

The Board also adopted a resolution setting the annual permit fee for farm labor housing water systems at $1,706 per system. To address concerns about new permit expenses received by Environmental Health Services from agricultural operators, many of whom are small family businesses, the County Executive’s Office will subsidize permit fees as the program phases in: 

Additional water system updates

The ordinance also updates County regulations for small domestic water systems serving up to 14 connections, clarifies landlord responsibilities for water quality and establishes water quality requirements for food facilities served by small water systems.

Environmental Health Services will continue to offer water testing for similar-sized systems serving other multifamily housing when complaints are received, as resources allow. The County may consider expanding regular oversight if testing identifies comparable concerns.

Property owners and residents with questions can contact Environmental Health Services at 650-372-6200 or visit Environmental Health Services.

The full ordinance is available through the County’s legislative portal. 

About San Mateo County 
Established in 1856, the County of San Mateo stretches from the Pacific Ocean to San Francisco Bay and includes 20 cities and rural communities. Home to more than 750,000 residents, it is one of California’s most diverse counties with an economy driven by innovation, life sciences, agriculture and international trade and travel. In addition to serving unincorporated communities, the County provides countywide services that support the health, safety and quality of life of residents. Learn more at smcgov.org.