Onsite Sewage System Permits
Acquiring an onsite sewage system (OSS) permit is a lengthy process. State and
local rules and regulations
require that you first hire a licensed professional who will evaluate your site, design a system, and complete
the permit application process with our office.
Permit Process You can download an extended version of the following information here.
The designer or engineer will evaluate your property by looking at the size and topography of
the site, soil conditions, proximity to surface water and other pertinent conditions. He or she
will then submit an application and design to Snohomish Health District that is unique and specific
to your property.
A sanitarian from SHD will review the site with the application and design to make sure that it
is an appropriate design in compliance with state and local rules and regulations. If the design is
denied, you and your designer will receive a letter that explains why. The designer is able to
address these concerns by submitting a redesign.
Once the design and application are approved, they will be mailed to you. An approved application
is valid for three (3) years and can be renewed for an additional three (3) year period with written
concurrence from the system designer, payment of a
renewal fee,
and review and approval from the SHD. Issuance of the installation permit is subject to conditions
specified in the application approval.
After you receive a permit for the septic system, you will need to hire a certified installer.
The designer will inspect the completed installation and submit an as-built to SHD.
A sanitarian then performs a final inspection and if approved, the system can be covered.
Construction of Onsite Sewage System for New Residences/Structures
An application approval is not a permit for installation of the onsite sewage disposal system.
An SHD sewage disposal installation permit for new structure or residence will not be issued before the
city/county building permit is issued and will remain valid concurrent with the city/county building permit.
If the building permit is withdrawn, revoked, or expires, the installation permit will no
longer be valid.
If an individual water supply (i.e. well) is proposed, you may be subject to the requirements of
House Bill 2929, the Growth Management Act, Section 63, regarding demonstration of an adequate and potable
water supply.
If an "Application for an Individual Water Supply" is submitted concurrently with an "Application for an
Onsite Sewage Disposal Permit", the fee is less than if it is submitted on its own.
Additional Information
Designer's and Engineer’s fees vary and are not set or regulated by the SHD or Department of Licensing.
The SHD is not a county or state agency, but instead is an independent municipal corporation, a District.
For specific information or questions, call (425) 339-5250 and ask to speak with a field sanitarian, or
email us.
For information regarding a well driller, contact the Department of Ecology at (425) 649-7000.
For information about licensed Designer or Professional Engineers check the Washington State Department of
Licensing web site
or call 360.664.1568 for DOL Customer Service.
