There are three types of public water systems: Group A, Group B and Two-Party.  A Group A system is the largest type of system. Any system with more than 14 connections or that serves 25 or more individuals for 60 or more days per year is considered a Group A public water system.  All Group A systems are regulated by the State Department of Health Office of Drinking Water.

Mason County Public Health regulates all Group B Water Systems in Mason County.  A Group B water system serves from 1 to 14 connections AND less than 25 individuals per day.  The regulations governing public water systems are Washington Administrative Code (WAC) 246-290 for Group A systems and WAC 246-291 for Group B systems. These regulations can be found at the following web site: Department of Health 

Setbacks for Group A and Group B wells are available under the links below.  Group B water system approval is explained under the “Group B packet” link (below). Group A water system approval must be obtained through the State Department of Health Office of Drinking Water (see the link earlier in this paragraph).  A County Well Site Inspection is required for Group A water system approval (see link below).

The Two-Party water system serves two single-family residences. The process for obtaining approval of a two-party water system can be found under the “Two Party Packet” link (below). While a two-party water system is technically a public water supply, the rules have been changed to aid in the approval process.  The setbacks for a two-party well are the same as the individual well setbacks (see link below).