King County Code Title 21A controls house bulk through floor-area, lot-coverage, and height limits rather than a dedicated mansionization ordinance, with stricter standards in rural and Vashon Island zones to preserve neighborhood character.
Unlike Los Angeles, King County does not have a dedicated mansionization ordinance, but the Zoning Code (KCC Title 21A) controls oversize single-family homes through several tools: maximum lot coverage, floor-area-ratio limits in some overlays, structure height caps, and setback requirements. Rural Area, Vashon-Maury Island, and Snoqualmie Valley zoning use stricter floor-area and lot-coverage standards to protect character and critical areas under KCC Title 24. Cities inside King County apply their own bulk standards, with Seattle's neighborhood overlays and Bellevue's R-zones being notable examples. Local Services Permitting reviews bulk compliance during single-family permit review.
Building beyond the lot coverage, height, or floor-area limits in KCC Title 21A is a zoning violation, triggering stop-work orders, redesign requirements, and possible removal of nonconforming construction.
Other ordinances people look up for this city. Green dot = verified primary-source excerpt.
Seattle, WA
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See how Seattle's anti-mansionization rules stack up against other locations.
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