Basement finish permits in City of Seattle: fees, timeline & requirements (2026)
Everything you need to know about pulling a basement finish permit in City of Seattle, Washington — when one is required, what it costs, how long review takes, what documents are required, and which inspections you can expect. Cited to Seattle Department of Construction & Inspections (SDCI).
When does a basement finish need a permit in City of Seattle?
Adding habitable rooms requires Construction Permit. Egress window required for any sleeping room (2021 IRC R310). Ceiling-height minimums and emergency-escape openings are common rejection reasons.
Required submittals
- floor plan w/ egress windows + ceiling heights
- electrical layout
- plumbing diagram
- mechanical / HVAC plan
- WSEC compliance form
Inspection sequence
- rough-in (electrical/plumbing/mechanical)
- framing
- insulation
- drywall
- final
Contractor specialties needed
general, electrical-01-or-02, plumbing, mechanical
Notes & caveats
Construction Permit (Addition/Alteration) if adding habitable space. Subject-to-Field-Inspection if scope is limited (no new bedrooms, no structural). Always: electrical, plumbing, mechanical permits for new fixtures/circuits/HVAC. WSEC applies to newly conditioned space.
How to apply
- 1. Confirm your parcel's zoning & overlays. Run an address lookup on the main permits page — we'll pull your specific lot polygon, zoning, setbacks, and any shoreline/ECA/historic overlays.
- 2. Assemble submittals (5).
- 3. Submit through the city portal: Seattle Department of Construction & Inspections (SDCI) ↗
- 4. Track review (typical: —). Respond to reviewer comments promptly.
- 5. Pay issuance fees (Construction Permit (Addition/Alteration). Plan-review fee scales with valuation. See SDCI 2026 Fee Estimator.) and pick up the permit. Inspection card travels with the job.
