Designing and building an on-site sewage system (OSS) on your property can be 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.
The Snohomish Health District reviews septic system designs for single-family homes and small businesses (systems less than 3,500 gallons per day). The Washington Department of Health enforce regulations for larger sewage systems in Snohomish County.
Septic permit services
The Snohomish Health District provides professionals and residents in the county with the following septic permit services:
- Certification and licensing of septic installers, pumpers and monitoring and maintenance specialists within Snohomish County
- Complaint investigations and enforcement
- Drain field repair designs for owner-occupied residences
- Field and regulatory review of proposed on-- site sewage disposal systems
- Operational reports for existing systems
- Technical assistance to the general public
Septic permit process steps
- You must hire a septic system designer or professional engineer to evaluate your property. The licensed septic professional will submit your on-site sewage application and design to the Snohomish Health District
- A sanitarian from the Snohomish Health District will then review your property with the application and design to make sure they comply with state and local regulations
- If your design is not approved, you will receive a letter of explanation and may submit a redesign after addressing the outlying issues
- Once your design and application are approved, you will be mailed an application approval that will be valid for 2 years. You can renew the approval for an additional 2-year period from the system designer, with application and payment of a renewal fee, and review and approval from the Snohomish Health District)
- Hire a certified installer to request the permit be issued for installation.
- A designer must inspect the completed installation and submit an as-built to the Snohomish Health District
- A sanitarian from the Snohomish Health District will perform and approve a final inspection
Constructing your on-site sewage disposal system
When constructing an on-site septic system in Snohomish County, please be aware of the following rules and regulations:
- A septic application approval is not a permit for the installation of a septic system. Permits for new structures or residences are not issued until the city or county building permit is issued
Note: If the building permit is withdrawn, revoked, or expires, the installation permit will no longer be valid.
- If an individual water supply such as a well is proposed, you may be subject to the requirements of House Bill 2929, the Growth Management Act (PDF), Section 63, regarding the demonstration of an adequate and potable water supply
- If the Application for an Individual Water Supply Site Inspection is submitted concurrently with the Application for an Onsite Sewage Disposal Permit, the fee is less than if it is submitted on its own