Water Supply

Water Supply Program


The purpose of a Water Supply program is to protect public health and prevent disease by assuring that domestic water served by water systems is safe, potable, available in adequate quantity and protected against contaminating backflow. This is achieved by ensuring compliance with Federal and State laws, regulations and local ordinances. In Sierra County, Public Water systems are regulated by the California Water Boards, Division of Drinking Water District 02. Sierra County Environmental Health has regulatory authority for the smaller systems called “State Small Water Systems”.

​Public Water System is defined as a system that provides water for human consumption to 15 or more connections or regularly serves 25 or more people daily for at least 60 days out of the year. Public water systems are divided into the following categories:

  • Community Water System (CWS): A public water system that has 15 or more service connections used by year-long residents OR regularly serves at least 25 year-long residents of the area served by the system.
  • Non-transient Non-community Water System (NTNC WS): A public water system that is not a community water system that regularly serves at least 25 of the same persons during six months of the year. Examples are schools and businesses that provide their own water.
  • Transient, Non-Community Water System (TNC WS): Serves drinking water to 25 or more individuals at least 60 days out of the year, but does not meet the requirements of a community or non-transient non-community water system. An example is a restaurant, campground, or church.

County Regulated State Small Water Systems Definition:



  • State Small Water System (SSWS): These are not public water systems, but they serve water for human consumption through at least 5, but not more than 14 service connections and do not regularly serve more than 24 year-long residents.


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