House or building remodels or expansions

How to apply for house or building remodel or expansions

For detailed guidance, see: How to Apply for a Building Application (862 KB)

IMPORTANT: Building Application approval is required before most building permits can be issued so that Public Health—Seattle & King County can review the project for any impacts to your septic system.

1. Identify the right building application type and required documentation.
• For guidance on identifying the right application type, see the Public Health Permit Center Septic Glossary (466 KB).
2. Apply for the relevant application type in the Public Health Permit Center and pay the associated fee.
3. Track your application status by navigating to “My Work” and selecting the relevant application in the Permit Center. You will get an email when the status of your application has changed.

Some projects may require evaluation by a licensed septic professional depending on the scope of the remodel and condition, location, and age of your septic system. 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. For example, a house with an older septic system and your proposal is to tear the house down to the foundation and rebuild, it would require a new septic system. Call the King County Septic Expert 206-477-8177 to ask about your potential project.