Washington permits
Do you need a permit in Washington?
Washington enforces the Washington State Energy Code (WSEC) and Washington State Building Code, which are stricter than the IECC and IRC baselines. Permits are issued at the city or county level. The Department of Labor and Industries (L&I) regulates contractor registration; specific trades (electrical) require L&I licensing. Seismic provisions apply to most of western Washington (Seismic Design Category D2).
Free calculator
These are statewide ranges. Get your exact Washington cost for your zip code and project size.
Can a homeowner pull the permit?
Yes, in most cases. Owner-occupied primary residences. Cannot pull permits for resale within 12 months. Electrical work in WA requires L&I electrical license for most non-trivial work.
Where to file: City building department for incorporated areas, county for unincorporated. Seattle uses SDCI; King County uses MyBuildingPermit; Pierce and Snohomish counties have their own portals. Plan review takes 4-12 weeks in Seattle for non-trivial work, 1-4 weeks elsewhere.
Permits by trade in Washington
| Trade | When required | Citation | Typical fee | DIY? |
|---|---|---|---|---|
| Plumbing | In-wall work, fixture changes, water heater, gas | Uniform Plumbing Code (WA-amended) | $100-$400 | Conditional |
| Electrical | New circuits, panel work, service upgrades, EV charger, solar | WA Electrical Code; L&I rules | $100-$400 | Conditional |
| Mechanical (HVAC) | Heat pump install, ductwork, ERV/HRV, refrigerant | WA Mechanical Code; WSEC | $150-$500 | No |
| Building (structural) | Additions, ADUs, structural modifications, seismic retrofits | WA Residential Code | $200-$2,000 | Yes |
| Roofing | Re-roofs, structural deck repair | Local jurisdiction | $100-$400 | Yes |
| Seismic retrofit | Cripple wall bracing, foundation anchor bolts on pre-1980 homes | WA Existing Building Code | $200-$500 | Yes |
Hover a Conditional or No entry for the homeowner rule. Always confirm with your local building department, since requirements vary by jurisdiction.
Ready to build
Get the full plan for your project
A Project Blueprint gives you the materials list, tool inventory, Washington permit steps, and a step-by-step build sequence, calibrated to your zip. Human-reviewed before delivery.