Public Water Systems

The Napa County Public Water System Program is in place to ensure that safe and potable drinking water is available by identifying risk factors that contribute to acute and chronic illness and working with water system operators to minimize these risks.

Napa County has a contract with the California Department of Public Health to oversee water systems with less than 200 service connections. These water systems include the following classifications:

  • Community water systems are public water systems which serve at least 15 service connections used by yearlong residents or regularly serve at least 25 yearlong residents.
    • Example: A mobile home park with 15 or more mobile homes and/or 25 or more residents.
  • Nontransient noncommunity water systems are public water systems that are not community water systems and that regularly serve at least the same 25 persons over 6 months per year.
    • Example: A winery or other business with 25 or more full or part time, permanent employees.
  • Transient noncommunity water systems are public water systems which serve at least 15 service connections or 25 or more persons for at least 60 days of the year.
    • Example: A winery with less than 25 employees that has public wine tasting with an average of 25 or more visitors for 60 days of the year.
  • State small water systems are systems which serve 5 to 14 service connections and do not serve drinking water to more than 25 individuals for more than 60 days of the year. In Napa County, these systems operate the same as transient noncommunity water systems.
    • Example: A well that serves 5 houses or mobile homes.

Systems that serve less than 25 individuals and only serve a food facility may qualify for reduced requirements under the CalCode exemption, and small systems with potable water, no food facility and that provide bottled may qualify for a Handwashing exemption. Contact the Department of Environmental Management for additional information.

Useful Water System Information

Helpful links