County Building Permits
King County, WA - 2026 Building Permit Guide
How to apply for a building permit in unincorporated King County, Washington. Permit authority, application steps, fees, and inspection requirements.
Quick Start
Verify property is in unincorporated King County.
Projects that usually need a permit
- Most construction
- New construction and additions
- Remodels and structural alterations
- Roofing, windows, siding, and exterior changes
- Plumbing, mechanical, and electrical work
Permit Authority
All unincorporated properties within King County (not within any incorporated city).
- Department
- King County Department of Permitting and Environmental Review (DPER) - Permitting Division (now part of Department of Local Services)
- Address
- King County Chinook Building, 401 5th Ave, Suite 100, Seattle, WA 98104
- Phone
- 206-477-3675
Online Permit Portal
Platform: King County Portal • Account required: No • Submission: Online only
Additional resources:
Application Process
- Verify property is in unincorporated King County
- Verify proposed use is allowed per KCC 21A.08
- Check prerequisites: Public Health approvals (septic, well, gas piping), Critical Areas Alteration Exception, Drainage Adjustment, Flood Permits, Historic Preservation Approval, Roads Variances
- Prepare documents: cover sheet, site plan, civil engineering plans, architectural plans, structural plans, mechanical/plumbing plans, energy code compliance forms
- Submit application online or in-person
- Pay fees at intake
- Multi-department plan review
- Permit issuance upon approval
Typical processing time: Varies by permit type and complexity.
General Requirements
A building permit is required for most construction in unincorporated King County.
Required Documents
- Completed permit application
- Cover sheet with property information
- Site plan with critical areas
- Civil engineering plans
- Architectural plans
- Structural plans
- Mechanical/plumbing plans
- Energy code compliance forms
- Water and sewer certificates (or Public Health approval for well/septic)
- Permit validity
- Varies by permit type.
- Building code
- 2021 Washington State Building Code with King County amendments
- Contractor requirements
- Contractors must hold a valid Washington State L&I registration.
Fees
- Payment note
- Online or in-person payment
Fees change. Verify current amounts at the official fee schedule (effective Current).
Work That Does NOT Require a Permit
- Similar to state exemptions
Important: Contact DPER for specific unincorporated area exemptions.
Inspections
How to Schedule
- Contact DPER (phone)
- Schedule online (if available) (online)
- Inspection hours
- Monday-Friday, 8:00 AM - 4:30 PM
Typical inspection sequence: Varies by project type
Additional Resources
- Building code: 2021 Washington State Building Code with King County amendments
- Verify contractor license: WA L&I Contractor Lookup
- Commercial Building Permit Checklist
- Residential Building Permit Checklist
- Seattle-King County Public Health (Plumbing/Gas)
- WA State L&I (Electrical)
- License lookup guide: Washington Contractor License Requirements
- Contract template: Washington Homeowner-Contractor Agreement
- Washington hub: Washington Contractor License & Permit Hub
Information on this page was last verified: 2026-04. Permit rules and fees change — confirm current requirements directly with the King County Department of Permitting and Environmental Review (DPER) - Permitting Division (now part of Department of Local Services) before applying.
Frequently Asked Questions
King County Building Permit FAQ
- Do I need a building permit in unincorporated King County, WA?
- A building permit is required for most construction in unincorporated King County.
- How do I apply for a building permit in unincorporated King County, WA?
- To apply for a building permit in unincorporated King County, WA, follow these steps: 1. Verify property is in unincorporated King County 2. Verify proposed use is allowed per KCC 21A.08 3. Check prerequisites: Public Health approvals (septic, well, gas piping), Critical Areas Alteration Exception, Drainage Adjustment, Flood Permits, Historic Preservation Approval, Roads Variances 4. Prepare documents: cover sheet, site plan, civil engineering plans, architectural plans, structural plans, mechanical/plumbing plans, energy code compliance forms 5. Submit application online or in-person 6. Pay fees at intake 7. Multi-department plan review 8. Permit issuance upon approval
- How long does it take to get a building permit in unincorporated King County, WA?
- Building permit processing times in unincorporated King County, WA typically run Varies by permit type and complexity.. Timelines can vary based on project complexity and current department workload.
- What work is exempt from building permits in unincorporated King County, WA?
- Not all construction work requires a permit in unincorporated King County, WA. The following work is generally exempt: Similar to state exemptions. Note: Contact DPER for specific unincorporated area exemptions. When in doubt, confirm with the local building department before starting work.
- How do I schedule a building inspection in unincorporated King County, WA?
- Once your permit is issued and work reaches an inspection milestone, you can schedule a building inspection in unincorporated King County, WA via: Contact DPER, Schedule online (if available).
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