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Private Water Systems

Different Types of Regulated Water Supply Systems

The following was written by Karen Giovannini, reviewed by Cynthia Lee, California Department of Public Health.

When well water is the source of water for projects that allow the public access to the water via restrooms, living/overnight stays or other means, you will be required to submit an application for and obtain a water supply permit either from a county or state agency, depending on the category of water system your activities meet. 

The requirements for water system permits is contained in the California Code of Regulations, Title 22.  You will need to request a water supply permit application from the appropriate State or County agency. The permit application process requires a variety of information to be submitted regarding the well, piping, tanks, valving, treatment and quality of water which is determined by chemical and bacteriological samples taken from each well or spring source.

The goal is to assure you can provide a safe and potable water supply at all times. 

Pond and Streams

CDFW Lake & Streambed Alteration Program 

Types of Regulated Water Systems

There are two water systems categories for operations using well or spring water:

  • State Small Water System – regulated by Sonoma County Environmental Health & Safety (EHS) 
  • Public Water Systems – regulated by California State Water Resources Control Board (SRWCB). Formerly regulated by CDPH.

State Small Water System

Regulated by Sonoma County Department of Environmental Health & Safety. NOTE: Even though it is called "State Small Water System" this system is regulated by the County.  This permit is obtained locally by contacting EHS at 707-565-6565 and is defined as:

  • Services 5 to 14 connections AND
  • Does NOT serve drinking water to more than an average of 25 individuals daily for more than 60 days out of the year. 

Requires quarterly water quality testing.

Public Water Systems

Regulated by State Water Resources Control Board, Division of Drinking Water. This permit is obtained through SWRCB at 50 D Street, Room 200, Santa Rosa, CA 95404, (707) 576-2145 and is defined as:

  • 15 or more connections AND/OR
  • Services 25 people per day for at least 60 days

There are many different types of Public Water Systems, see Introduction to Regulatory Requirements for Public Water Systems.

Applying for water supply permit

It is helpful to try to obtain the driller’s well log for your well or wells. Chemical and bacteriological sampling from your water source will be required. The type of samples required depends on your category of water system and the regulatory agency.Food Facilities with Private Water WellsThe regulator is determined by the type of ag/food processing, each will require initial and ongoing testing of the water supply: