Seattle, Washington Building Permits
Navigate building permits in Seattle, WA with our expert guide. Learn about the SDCI process, approval timelines, costs, and code requirements for your projects.
Wind
ASCE 7 basic wind speed: 110 mph (Exposure B/C varies)
Snow Load
Ground snow load: 25 psf
Flood
FEMA flood zones are concentrated along the Duwamish River and shoreline areas; specific building elevations apply.
Earthquake
Seismic Design Category D
Wildfire
Low risk generally; Wildland-Urban Interface (WUI) codes apply in specific forested perimeter areas.
Building Department
Seattle Department of Construction and Inspections (SDCI)
Approval Timeline
Residential permits take 4-8 weeks; Commercial permits typically range from 3-6 months depending on project complexity and revisions.
Common Requirements
Site plan, architectural floor plans, structural drawings, drainage control plans, and proof of legal access to utilities.
Zoning Information
Seattle uses a complex Land Use Code with various residential (SF, RSL, LR, MR, HR) and commercial (C1, C2) zones, often governed by Urban Village overlays.
Permit Costs
Fees are based on the total valuation of the work, typically ranging from $500 for small decks to thousands for multi-family developments.
Engineering Requirements
Engineering stamps are mandatory for structural work, foundation redesigns, and any major modifications affecting the building envelope.
Local Code Adoption
2021 Seattle Building Code (based on IBC/IRC with local amendments)
Typical Projects
ADU/DADU construction, home renovations, commercial tenant improvements, and multi-family high-rise development.