Cowlitz County Washington Energy Code Compliance
WSEC-R 2021 compliance information for builders and contractors in Cowlitz 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)
Cowlitz County Building & Planning
- Phone
- (360) 577-3052
- Address
- 207 4th Ave N, Kelso, WA 98626
- Hours
- M-F 8am-5pm
Last verified: 2026-04-19
Submittal notes
- Cowlitz County: Cowlitz County requires an approved Planning Clearance Certification (PCC) before building plan review can start.
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.
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 Cowlitz County
Coming soon as we gather receipt data from local contractors.
Information on this page may be out of date. Report outdated info →