King County Washington Energy Code Compliance
WSEC-R 2021 compliance information for builders and contractors in King County.
Code environment
Climate Zone
CZ4
Western Washington — moderate climate with lower minimum insulation requirements than CZ5.
Wall min R-20 or R-13+5ci · Ceiling min R-49 · Window max U-0.30 (WAC 51-11R-40202)
Radon Zone
Zone 2
Moderate radon potential — radon-resistant construction recommended but not mandated by state code.
Learn more →County building department
The county building department handles permits for unincorporated areas. Cities within the county may have their own permit offices — see below.
Authority Having Jurisdiction (AHJ)
Department of Local Services - Permitting Division
- Phone
- (206) 296-6600
- Address
- 919 SW Grady Way, Ste 300, Renton, WA 98057
- Hours
- M/Th 8:30am-3:30pm
- Portal
- Online permit portal →
- Notes
- uses MyBuildingPermit.com
Last verified: 2026-04-19
Submittal notes
- King County: King County requires a '2021 Energy Compliance Summary Sheet' specifying exact HVAC equipment specs (mini-splits ≥10.0 HSPF, air-to-water heat pumps ≥3.2 COP at 47°F), hot water loop volumes (≤16 oz between source and fixture), and solar-ready provisions.
- Seattle: Seattle: Third-party blower door test results must be physically posted near the electrical panel before final inspection.
- Bellevue: Bellevue layers the 2023 Washington Cities Electrical Code on top of WSEC-R 2021 — additional lighting budget calculations and heat system sizing forms are required beyond other MBP-consortium jurisdictions.
- Redmond: Redmond requires environmental checklist and critical areas report (SEPA) clearance before the building permit can issue.
Cities with their own building department
These cities have an independent permit office. If your project is inside city limits, contact the city — not the county — for permits.
Auburn
Auburn Community Development
Bellevue
Bellevue Development Services Permit Center
Bothell
Bothell Community Development Department
Burien
Burien Community Development Department
Federal Way
Federal Way Community Development
Issaquah
Issaquah Development Services Department
Kenmore
Kenmore City Hall
Kirkland
Kirkland Planning and Building
Mercer Island
Mercer Island Community Planning & Department
Newcastle
Newcastle Community Development/Permits
Sammamish
Sammamish Permit Center
Seattle
Seattle Department of Construction and Inspections
Snoqualmie
Snoqualmie City Hall
Ready to check your compliance?
Answer a few questions about your project and get a complete R406 credit summary you can submit with your permit application.
Start your WSEC compliance check →Typical project costs in King County
Coming soon as we gather receipt data from local contractors.
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