The Washington State Department of Health (DOH) is conducting an Environmental Justice Assessment on agency-proposed legislation that would change the definition of a “public water system” in RCW 70A.125.010(12) and WAC 246-290-020(1) and 246-291-010(51). The current definitions of a public drinking water system state that systems “with four or fewer connections all of which serve residences on the same farm” are not subject to regulation, but do not clarify if the exemption applies to Group A or Group B systems . The definitions in our state laws and rules need to be as strict as the federal Safe Drinking Water Act to ensure all water systems that meet the Group A threshold are regulated as Group A public water systems, without exception. We need a change in legislation (RCW) to allow clarification in state rules (WAC). This rule revision will: • Align state and federal definitions of a “public water system”, • Further clarify the difference between a Group A public water system and a Group B public water system, and • Clarify exclusions only from a Group B public water system for four or fewer connections to single-family residences on the same farm.