Napa County CA Water Department

Find Napa County, California water departments, districts, authorities, boards, and services. Water departments provide information on drinking water, treatment plants, sewage treatment, water conservation, and testing.


Calistoga Water Department 1232 Washington Street Calistoga CA 94515 707-942-2847


Napa County Water Department 804 1st Street Napa CA 94559 707-259-8600

Napa Water Billing 955 School Street Napa CA 94559 707-257-9508

Napa Water Department 1340 Clay Street Napa CA 94559 707-257-9521

St Helena Water Department 1480 Main Street St. Helena CA 94574 707-968-2745

About Napa County Water Departments

The Napa County Water Department or Water Utility is a government agency or private company that operates a public water system, which provides potable tap water directly to residential, commercial, industrial, and institutional customers in Napa County, CA.

You may contact the Water Department for questions about:
  • Water utility bills and payments
  • Napa County drinking water
  • Drinking water quality testing and safety
  • Water treatment facilities in Napa County, CA
Napa County Water Utility Companies

Water Departments in Napa County operate as an utility and are self-sustaining operations funded through user fees. Napa County water rates may be subject to approval from a state regulatory authority such as a California Public Service Commission or Utility Control Authority.

Public Drinking Water

Water Departments, or Water Companies in Napa County typically own the sources of drinking water they provide and must manage and maintain those sources and their surrounding areas. Surface sources include reservoirs, lakes, and rivers. Napa County groundwater sources can be found in pockets beneath the ground, which can be accessed by drilling wells. Maintenance of Napa County drinking water source sites and limitations on permitted activity around water sources helps minimize contamination. However, drinking water requires treatment prior to distribution to customers.

Water Treatment Facilities in Napa County, CA

Napa County water treatment facilities are used to remove contaminants and make drinking water safe for consumption. Treatment of water begins with the removal of the larger particles in the water through processes known as coagulation, flocculation, and sedimentation. After the large particles are removed, water is filtered through materials such as sand, gravel, and charcoal to remove dissolved particles. The final stage of treatment involves disinfection using chemicals or ultraviolet irradiation. Napa County Water Departments may add fluoride to water at this stage as part of a community health effort to support oral health in the general population. Water Departments are responsible for the day-to-day operations and maintenance of Napa County water treatment facilities. Equipment must also be periodically replaced and treatment processes may also be periodically upgraded.

From the treatment plant, water reaches its customers through a distribution system consisting of pipes, referred to as water mains, storage tanks, and pumping stations. Individual customers connect to water mains to bring public drinking water directly to their properties in Napa County, California.

Water Testing in Napa County

Water Companies typically have a laboratory or testing division responsible for monitoring the quality of tap water throughout the process, from source to distribution. California state regulations require Water Utilities to prepare and issue Napa County water quality reports to the general public several times per year.