All Group B systems are regulated by the Thurston County Environmental Health Division (Health Division). These
systems must comply with Article III [PDF] of the Thurston County
Sanitary Code, WA State requirements of
Chapter 246-291 WAC Group B Public Water Systems, and associated workbook Guideline for Group B Public Water System Approval.
For projects located within a city jurisdiction or Thurston County Coordinated Water System
Plan Urban Service Area [PDF], additional standards may apply.
One well serving two residences is considered a Group B public water system, but is placed in a separate classification as it has a different set of regulations
than those with 3 or more connections. These water systems are classified as 2-Party public water systems and are regulated by the Health Division. For more information, see 2-Party Water Systems.
NOTE: Expansion of a 2-Party Public water System to provide water service to additional Connections will require
the water system meet the Group B or Group A public water system requirements of
Article III [PDF] of the Sanitary Code. This includes a design of the proposed system
expansion by a qualified water system designer or engineer and subsequent approval by the Health Division or WA Dept of Health, if applicable.
Review Process / Final Approval
Staff will review the water system design and Preliminary Engineering Report and send a letter
granting preliminary water system approval, if all the requirements are met.
After the water system design has received preliminary approval and construction is completed, the engineer or water system designer shall inspect
the water system to assure compliance with the approved construction documents.
Within sixty (60) days of the inspection, the engineer or water system designer shall submit a completed Certificate of Inspection and Installation of
Public Water System Projects form along with the Final Engineering Report.
Staff will review the documents and grant final water system approval and the required sampling
frequency, if the requirements are satisfied.
Staff will sign the Certificate of Water Availability (COWA) after the water system has been granted final approval.
- Submit copy of an approved
Supplemental Application [PDF]. See Well Site Application/Inspection for requirements.
NOTE: An approved Well Site Application is required prior to drilling and before the Water System Design Application can be submitted.
- Submit a completed
Group B or 2-Party Water System Design Application [PDF]. Also submit with the application:
NOTE: If the water system is within a city jurisdiction or Thurston County
Coordinated Water System Plan Urban Service Area
[PDF], the Health Division will mail the application to the applicable jurisdictional authority
and will hold permit issuance until their review and comment is completed.
Complete application package requirements are outlined on the Well Site Supplemental Application [PDF],
Group B or 2-Party Water System Design Supplemental Application [PDF], and
Water System Design Guidelines [PDF].
Well Site Application/Inspection
Prior to drilling a new well or obtaining approval for an existing well, the location of the well must first be approved by the Health Dept. Submit a completed
Well Site Supplemental Application [PDF] package to the Permit Assistance Center with the applicable fee (see
Fee Schedule [PDF]). Also submit with the application:
- Project site plan — include the proposed well site, 100-foot sanitary control area around the well, any structures, all septic system components,
drainage ditches, stormwater infiltration ponds, and public roads within 200 feet.
- Proposed well site — location flagged on the property
NOTE: Complete application package requirements are outlined on the
Well Site Supplemental Application [PDF] and
Well Site Application Guidelines [PDF]).
Health Dept staff will review the well site application and issue approval if all requirements are met. (This includes an on-site evaluation of topography,
potential contaminant sources, and hydrologic suitability of the well location.) Once the well site has received approval, contact a licensed well driller to have the well drilled and tested for capacity and water quality.
NOTE: Prior to drilling, a Start Notification should be sent to both the Washington State
Department of Ecology and Thurston County Environmental Health Division, by the well driller. For additional
information and application form, see For Well Drillers Only.
Preliminary Engineering Report (Design Report)
A Preliminary Engineering Report, including detailed plans and specifications for the proposed water system, shall be
prepared and submitted by a Washington State licensed engineer or Thurston County certified water system designer for review and approval.
The preliminary report shall follow the guidelines in the Group B Workbook, including Satellite Management Agency (SMA) information (see below), draft documents (covenants,
easements, operations and management agreements), well driller's report, water quantity and quality reports, and construction documents.
Final Engineering Report
Upon completion of the water system construction, the engineer or designer shall inspect the system to assure compliance with the approved construction
documents. Within sixty (60) days, the engineer or designer shall submit a completed Certification of Construction and Inspection form, along with the Final
Engineering Report, to the Health Division.
It is important that all items listed in the plan approval letter are submitted in the report in order to avoid delaying the final review and approval of the project.
The final engineering report will be reviewed by Health Division staff and a letter will be sent to the system owner
(and a copy to the engineer or designer) upon approval. The letter will indicate the required sampling frequency. The system is now ready for use.
NOTE: Projects having staged construction shall submit certification document for each separate stage prior to approval and use of any segment.
Satellite Management Agencies
All new water systems shall be owned or professionally managed by an approved Satellite Management Agency (SMA). For the names of SMAs serving
Thurston County, see
List of Approved Satellite Management Agencies
It is important to contact the SMA prior to system design so that the agency's design and operating requirements are incorporated into the design. A draft
contract with the proposed SMA should be submitted with the Preliminary Engineering Report. If an SMA is unavailable, contact Thurston County Environmental Health.
Well Isolation Covenants
The owner of a public water supply is required to have physical control over the well isolation area (normally a 100-foot radius). Generally, this is
accomplished through the filing of protective covenants (either a
Declaration of Covenant [PDF] or
Restrictive Covenant [PDF], or both) for the well isolation area.
- Declaration of Covenant — filed when the water supplier owns all or part of the area in the sanitary control area
- Restrictive Covenant — filed when someone other than the water supplier owns portions of the sanitary control area
It is important that the covenants are obtained prior to drilling a well or completing the water system design (see
Covenant Fact Sheet [PDF] for instructions and examples).