Conditions for approving different water sources in King County

Group A Water systems

For new development, you must provide a Certificate of Water Availability (236 KB) from the Group A saying they are willing and able to supply water to the property.
For properties already connected to a Group A, a copy of the water bill or similar verification they are connected will be acceptable.

Group B Water Systems

Only approved Group B water systems may be used as an approved water source
Individuals seeking to use a Group B water system for their project should be able to provide a water system approval letter:

For Water systems created before 2011 that were approved by King County, check the King County Septic and Group B Records
For water systems created after 2011 that were approved by the state Department of Health, contact the water system purveyor/manager for available records

Provide evidence that the property is authorized to connect to the water system, according to its originally approved design. Group B systems cannot allow more connections than approved in the original design, unless it goes through an official expansion process. Evidence includes:

Approval letters
Approved designs
Water use agreement
Informational notices on title
Certificate of Water Availability from the purveyor of Group B

Using a Group B water system for an onsite sewage system requires:

Satisfactory water quality test results within the last year
Satisfactory pump test results
A 100' protective radius around the well free from potential contamination sources

You must show the necessary covenants protecting the water source:

Individual private wells

New or existing wells must receive department approval for on-site sewage system projects.
Using a private well for an onsite sewage system requires:

Satisfactory water quality test results
Satisfactory pump test results

Existing wells may be required to provide pump test results

A 100' protective radius around the well free from potential contamination sources

You must show the necessary covenants protecting the well:
- Declaration of Covenant: Private water supply
- Restrictive Covenant: Private individual well

Existing private spring

Existing private springs must receive department approval for on-site sewage system projects
Using an existing private spring for an onsite sewage system requires:

Satisfactory water quality test results
A 200' protective radius around the well free from potential contamination sources

You must show the necessary covenants protecting the spring:

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