Building Permits in King County, Washington

Exemptions: Washington adopts the International Residential Code statewide with amendments in Chapter 51-51 WAC (State Building Code Council); Chapter 11 and Chapters 25-43 are not adopted (energy is under WAC 51-11R, plumbing under WAC 51-56, electrical under WAC 296-46B). Chapter 51-51 WAC does not amend IRC Section R105, so the model IRC R105.2 exemptions apply (e.g., 200 sq ft accessory structures, 7 ft fences, 4 ft retaining walls, sidewalks/driveways, finish work). Local jurisdictions enforce the code and may amend it under RCW 19.27, so always verify locally.

Exemptions: Most decks require a building permit; IRC R105.2(10), adopted statewide by Chapter 51-51 WAC without amendment to R105.2, exempts only decks not exceeding 200 square feet (18.58 m2) in area, not more than 30 inches (762 mm) above grade at any point, not attached to a dwelling, and not serving the exit door required by Section R311.4. Attached decks or decks exceeding any of these limits need a permit. Local jurisdictions may amend, so confirm with the local building department.

Exemptions: Electrical work in Washington is not covered by the residential building permit: per WAC 51-51-003, the IRC electrical chapters (34-43) are not adopted and the Electrical Code is regulated by chapter 296-46B WAC or as adopted by the local jurisdiction, meaning electrical permits are issued by the Washington Department of Labor & Industries or by cities with their own electrical programs. Most electrical installations require a permit, with limited exemptions (e.g., minor like-in-kind repair) defined in WAC 296-46B. Verify with L&I or the local electrical authority.

Exemptions: Fences not over 7 feet (2,134 mm) high are exempt from a building permit under IRC R105.2(2) as adopted statewide by Chapter 51-51 WAC without amendment to R105.2. Fences taller than 7 feet require a permit. Local zoning codes frequently impose lower height limits, so check the city or county.

Exemptions: Roof replacement is not listed among the work exempt from permit in IRC R105.2 as adopted statewide by Chapter 51-51 WAC (R105.2 is unamended), so a building permit is generally required for residential reroofing in Washington. Only ordinary repairs and finish work are exempt. Some local jurisdictions adopt their own reroof exemptions or streamlined permits, so verify locally.

Exemptions: Retaining walls not over 4 feet (1,219 mm) in height, measured from the bottom of the footing to the top of the wall, are exempt from a building permit unless supporting a surcharge, per IRC R105.2(3) as adopted statewide by Chapter 51-51 WAC without amendment to R105.2. Walls over 4 feet or supporting a surcharge require a permit and typically engineering. Local jurisdictions may amend, so verify locally.

Exemptions: Under IRC R105.2(1) as adopted statewide by Chapter 51-51 WAC (which leaves R105.2 unamended), no building permit is required for a one-story detached accessory structure provided the floor area does not exceed 200 square feet (18.58 m2). Larger or multi-story accessory buildings require a permit. Local jurisdictions may amend this threshold and zoning/setback rules still apply.

Exemptions: Plumbing in Washington is regulated by the Uniform Plumbing Code adopted statewide in Chapter 51-56 WAC (the IRC plumbing chapters 25-33 are not adopted per WAC 51-51-003), and water heater installation or replacement is not among the statewide permit exemptions, so a plumbing permit (plus mechanical/gas for fuel-fired units) is generally required from the local jurisdiction. Only minor repairs such as stopping leaks and clearing stoppages are typically exempt. Local permitting procedures vary, so confirm with the city or county.

Building department website ↗

Phone: 206-296-6600

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