On-site sewage/septic repair or replacement
A repair proposal and permit are required when any change(s) or system replacements are made to your septic system. Below is a step-by-step guide for this process depending on what type of repair permit you need.
Septic repair permit
- Contact a certified master installer in King County.
- Master installer submits a repair proposal to Public Health – Seattle & King County.
- If approved by Public Health – Seattle & King County, an application for permit is submitted by the master installer. If disapproved, a new or modified proposal must be submitted, possibly by a licensed designer.
- After permit is issued by Public Health – Seattle & King County, repair is completed by master installer.
- Repair is inspected by Public Health – Seattle & King County.
- As-built of repair is submitted to Public Health – Seattle & King County by the master installer.
- As-built of replacement septic system submitted by the designer or qualified professional engineer.
Download repair proposal form for on-site sewage system (358 KB)
Septic replacement permit
- Depending on size of replacement, contact a certified designer, master installer or qualified professional engineer.
- Your septic system professional submits a design proposal, called a 'site application', to Public Health – Seattle & King County.
- If approved by Public Health – Seattle & King County, an application for permit is submitted by your septic system professional. If disapproved, a new or modified proposal must be submitted.
- The designer or qualified professional engineer conducts a pre-installation (also known as, stub-out) inspection and gives report to the master installer and Public Health – Seattle & King County.
- After permit is issued by Public Health – Seattle & King County, the installation is completed by master installer.
- Installation is inspected by the designer.
- Installation is inspected by Public Health – Seattle & King County.
Download site design application form for individual on-site sewage system (221 KB)
Building permit
- You may apply for this review prior to or at the same time as the Building Department's review of your application. Please consult with your building official.
- While preparing your application, it is important to accurately describe the location of all septic system components on your site plan. Search and download a drawing of your septic system (as-built drawing).
- The application must be filled out with 3 complete packages.
- Each application is reviewed by an inspector and receives a site visit. Examples the inspector are looking for includes:
- Age of septic system
- Condition of system
- Type of system
- Location of system as compared to area of remodel
- Presence of a reserve drainfield area
- Size of remodel
- existing square footage vs. square footage being added
- Type of addition(s)/remodel
- are bedrooms being added?
- Water source
- a drinking water well requires certain setbacks to structures
- structures must be served by an approved water source
- Record drawing and past permit history
- Due to the scope of your remodel and condition, location and age of your septic system, you may be required to have the septic system evaluated by a licensed septic professional or in some cases a new on-site sewage/septic system meeting all current regulations may be required. The inspector will notify you in writing what this evaluation must include and what type of septic professional must be contacted.
- You may also be required to upgrade or replace your septic system.
Download the application for health department approval of building permit (357 KB)
Limited repair permit
- Under certain circumstances, you may have to contact a certified master installer or on-site system maintainer in King County. If you have a conventional gravity septic system, the repair may be completed before obtaining a permit. If you have any questions about when to apply for a repair permit, please call our office at 206-477-8050.
- Master installer or on-site system maintainer submits repair proposal for limited repair to Public Health – Seattle & King County.
- Repair is completed by the master installer or on-site system maintainer.
- Record of repair is submitted to Public Health – Seattle & King County by the master installer or on-site system maintainer.