Washington Building Permits — Complete Guide (2026)
Find, Apply & Track Permits in Cities and Counties Across Washington
Washington state has strong ADU laws and progressive building standards. The Puget Sound region has high permit volume and increasingly streamlined online systems. Seismic requirements affect all structural permits in Western Washington.
How building permits work in Washington
Building permit requirements and processing times in Washington vary by city and county. Use the links below to apply, check status, schedule inspections and find permit information for your location.
Learn the step-by-step permit process →Not sure where to apply?
Enter your city or address to find your permit office.
Permit costs by type — Washington
| Permit Type | Fee Range | Processing Time | Notes |
|---|---|---|---|
| Electrical | $100–$300 | 1–5 days | Licensed electrician required statewide |
| Plumbing | $85–$250 | 1–5 days | Water heater replacement always permitted |
| HVAC / Mechanical | $100–$300 | 2–6 days | Heat pump adoption among highest in US |
| Roofing | $150–$400 | 1–5 days | Re-roof permit required statewide |
| Deck / Patio | $160–$480 | 2–5 weeks | Seismic connections required for attached decks |
| Room Addition | $450–$1,100 | 3–7 weeks | Seismic engineering often required |
| New Construction | $800–$2,500 | 3–8 weeks | Seismic plus energy code compliance |
| ADU | $450–$1,100 | 2–6 weeks | HB 1337 (2023) — cities cannot unreasonably deny |
| Solar | $100–$300 | 1–5 days | Net metering makes solar very attractive |
| Garage Conversion | $320–$800 | 2–5 weeks | Often processed as ADU in WA |
Major Washington cities — apply online
Most Washington building permits are issued by cities. Click your city to access the permit portal, apply online, or check permit status.
Permit costs by county — top Washington counties
County building departments handle unincorporated areas. Click a county to access its permit portal directly.
How to get a building permit in Washington
Find your jurisdiction's permitting portal
Washington's 39 counties and major cities each have their own systems. Seattle uses the Seattle Services Portal. King County handles unincorporated areas. Eastern Washington cities are generally simpler.
Understand seismic requirements
If your project involves structural work, seismic design compliance is required in Western Washington. This typically means an engineering review that adds cost and time to plan check.
Energy code compliance
Washington's energy code (WSEC 2021) is among the strictest in the US, requiring high insulation levels and heat pumps for new construction in many cases.
Submit application
Trade permits can typically be submitted online in major cities. Structural projects require plan sets with engineering for seismic loads.
Inspections
Washington cities generally have good inspection availability with online scheduling. Rural Eastern Washington may have limited inspector availability — schedule well in advance.
ADU permits in Washington — what you need to know
🏠 Washington ADU-friendly status: Yes — #2 in US after California
Washington passed HB 1110 in 2023 requiring cities to allow duplexes and ADUs in all residential zones statewide. Seattle has one of the most progressive ADU programs in the US — allowing up to 2 ADUs per lot since 2019. Processing times in Seattle run 4–12 weeks due to high demand.
Find a licensed Washington contractor
Washington requires licensed professionals for most permitted work. Always verify a contractor's license before hiring — it protects you and is required for most permit types.
General Contractors
Find pre-screened general contractors for your Washington home project. Compare quotes on permitted work.
Find a Contractor →Verify WA Registration
Verify your contractor holds a valid Washington State Department of Labor & Industries license before any permitted work begins.
Verify WA Registration →Electricians & Plumbers
Specialty-licensed electricians and plumbers are required for all permitted electrical and plumbing work in Washington.
Learn More →Ready to get started? Browse verified, licensed contractors serving Washington homeowners and get free quotes on your project.
🔍 Find a Contractor Near YouFrequently asked questions — Washington permits
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