There are approximately 120 existing Group B Water Systems that are overseen by the Environmental Health Division (EHD) and files are maintained on each system.  Group B Public Water Systems have 3 to 14 service connections and less than 25 people per day or serves 25 or more people per day during fewer than 60 days per year. A well site inspection is required for these systems prior to drilling a well.  EHD reviews and approves Group B Water Systems serving 3 to 9 service connections, which require hiring an engineer to submit a design to this office for review.  Group B systems are required to test for coliform bacteria every 12 months and nitrate every 36 months (Water Lab link).

All Group B water systems serving 10 to 14 service connections are reviewed and approved through Washington State Office of Drinking Water (ODW) (these will also require the hiring of an engineer & submittal of a design for review).  ODW regulates larger public water systems with ten or more connections, and or water systems serving 25 or more people for 60 or more days under WAC 246-290.

Scott Evans
Environmental Health Specialist II
Group B Water Systems / Drinking Water & Wells

What do I do if I have an Unsatisfactory Water Sample? 


Group B Publications



Additional Resources and Publications