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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.

Have a septic question?

Have a septic question?

If you have technical septic questions, call the Septic Expert at 206-477-8177 or find a professional.

Septic repair permit

  1. Contact a certified master installer in King County.
  2. Master installer submits a repair proposal to Public Health – Seattle & King County.
  3. 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.
  4. After permit is issued by Public Health – Seattle & King County, repair is completed by master installer.
  5. Repair is inspected by Public Health – Seattle & King County.
  6. As-built of repair is submitted to Public Health – Seattle & King County by the master installer.
  7. 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

  1. Depending on size of replacement, contact a certified designer, master installer or qualified professional engineer.
  2. Your septic system professional submits a design proposal, called a 'site application', to Public Health – Seattle & King County.
  3. 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.
  4. 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.
  5. After permit is issued by Public Health – Seattle & King County, the installation is completed by master installer.
  6. Installation is inspected by the designer.
  7. Installation is inspected by Public Health – Seattle & King County.

Download site design application form for individual on-site sewage system (221 KB)

Building permit

  1. 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.
  2. 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).
  3. The application must be filled out with 3 complete packages.
  4. 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
  5. 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.
  6. 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

  1. 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.
  2. Master installer or on-site system maintainer submits repair proposal for limited repair to Public Health – Seattle & King County.
  3. Repair is completed by the master installer or on-site system maintainer.
  4. Record of repair is submitted to Public Health – Seattle & King County by the master installer or on-site system maintainer.
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