Information may be inaccurate or out of date. Always confirm permit requirements with the official city, county or state website before you start work. Read our disclaimer

Building Permits in Seattle, Washington

Part of King County.

We checked Seattle's own official pages for 8 types of projects (shed, fence, deck, roof, garage, tree removal, adu, demolition). Permits are issued by City of Seattle building department. Every rule below links to the page it was taken from, so you can confirm it before you start work. Last verified September 29, 2026.

Verified permit information is available for 6 project types in Seattle.

Verified Permit Categories

Seattle rules in detail

Shed

Size limit (sq ft)
120 source: seattle.gov
Conditions
All other sheds require a permit; most require only a subject-to-field-inspection permit source: seattle.gov
Setback (ft)
10-15 feet front, five feet side (NR zones) source: seattle.gov

Fence

Height limit (ft)
8 source: seattle.gov
Conditions
A construction permit is required if the fence has masonry or concrete elements over 6 feet, or if it will be located in a flood-prone area. source: seattle.gov

Deck

Conditions
A permit is required for a deck that is more than 18 inches above the ground, is a roof deck, or is in an environmentally critical area (ECA). source: seattle.gov

Roof

Size limit (sq ft)
500 source: seattle.gov
Exempt from a permit
A permit is not required for re-roof work at one- and two-family homes and townhouses if no changes are made to the building envelope other than adding or replacing insulation, and the insulation value is equivalent to or better than the existing structure. source: seattle.gov

Garage

Conditions
The property where you will build your garage must not be in an environmentally critical area. source: seattle.gov
Setback (ft)
20 ft front, 5 ft side source: seattle.gov

Tree Removal

Permit required
Depends source: seattle.gov

ADU

Conditions
While some property may be large enough to have four or more units, only two of them may be ADUs. source: seattle.gov

Demolition

Conditions
You must meet asbestos survey requirements before you can obtain a demolition permit. source: seattle.gov
Permit required
Yes source: seattle.gov

Not yet verified

These permit categories do not yet have enough verified information to publish a linked permit page.

  • Deck
  • Roof
  • Pool
  • Patio
  • Pergola
  • Carport
  • Solar Panels
  • HVAC
  • Electrical
  • Plumbing
  • Driveway
  • Home Addition
  • Windows
  • Water Heater

Where to apply

City of Seattle building department · official website · apply online

Washington statewide rules

State defaults apply everywhere in the state; cities and counties may add stricter local rules.

Issued by
State Building Code Council source: app.leg.wa.gov
Building code
2021 edition of the International Residential Code source: app.leg.wa.gov
Local changes allowed
Limited source: app.leg.wa.gov

ADU

Conditions
A city or county must allow at least two accessory dwelling units on lots in urban growth area zoning districts that allow single-family homes. source: app.leg.wa.gov

Permit guides