Washington's adopted International Residential Code under RCW 19.27 makes fire sprinklers mandatory in townhouses and multifamily buildings; single-family fire sprinklers are typically required only when triggered by access, water-supply, or local amendments.
King County follows the Washington State Building Code (RCW 19.27), which adopts the International Residential Code (IRC) and International Building Code (IBC) statewide. Fire sprinklers (NFPA 13D) are required in new townhouses and multifamily structures. For single-family detached homes, sprinklers are not universally required at the state level, but local fire-code amendments, long driveways, or insufficient hydrant flow can trigger them in unincorporated King County and many of the county's 39 cities. Plan review is handled by King County Department of Local Services Permitting in unincorporated areas and by city building departments elsewhere, with fire-district sign-off.
Building or remodeling without required sprinklers, or bypassing sprinkler heads, is a building- and fire-code violation under IRC, IBC, and RCW 19.27, with stop-work orders and corrections required.
King County, WA
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King County, WA
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King County, WA
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King County, WA
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King County, WA
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King County, WA
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See how King County's fire sprinkler requirements rules stack up against other locations.
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