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When a permit is required
Permit triggers and exempt work for Mercer Island
A building permit is required for most construction within the City of Mercer Island.
- Exempt One-story detached accessory structures under 200 sq ft
- Exempt Decks under 30 inches above grade
- Exempt Fences under 6 feet in height
- Exempt Retaining walls under 4 feet
Note: Mercer Island has solar-friendly policies. Verify exemptions before proceeding.
- Completed permit application
- Site plan
- Construction plans (PDF format)
- Architectural plans
- Mechanical/plumbing plans
- Building code
- 2021 Washington State Building Code (with local administrative provisions aligned to MyBuildingPermit regional model code)
- Permit validity
- Varies by permit type.
- Contractor requirements
- Contractors must hold a valid Washington State L&I registration.
Source: Community Planning & Development (CPD) - Building Team ↗
Application process
Typical processing: Varies by permit type.
- 01 Access MyBuildingPermit.com
- 02 Create account
- 03 Select Mercer Island as jurisdiction
- 04 Complete online application forms
- 05 Upload PDF plans to submittal portal
- 06 Pay fees online
- 07 City staff reviews application
- 08 Receive electronic permit upon approval
Typical processing time: Varies by permit type.
Source: Community Planning & Development (CPD) - Building Team ↗
Required inspections
Scheduling and sequence
- MyBuildingPermit.com (online)
Source: Community Planning & Development (CPD) - Building Team ↗
Frequently asked
Common questions about Mercer Island permits
01 Do I need a building permit in Mercer Island, WA? ▸
02 How do I apply for a building permit in Mercer Island, WA? ▸
03 How long does it take to get a building permit in Mercer Island, WA? ▸
04 What work is exempt from building permits in Mercer Island, WA? ▸
05 How do I schedule a building inspection in Mercer Island, WA? ▸
Educational reference. Permit rules and fees change — confirm current requirements directly with Community Planning & Development (CPD) - Building Team before applying. Jaspector is not legal advice.