King County, WA Home Business: Signage Rules (2026)

Home occupations in unincorporated King County are permitted one identification sign under KCC 21A.30.080 and the sign regulations in KCC 21A.20. The sign must not exceed 2 square feet in area, must be attached flat to the dwelling or accessory building, and cannot be internally or externally illuminated. Freestanding pole signs, yard signs, banners, flashing lights, LED message boards, and rooftop signs are all prohibited for home occupations in residential zones. The sign may identify the business name and contact information but cannot advertise products, promotions, or prices. Temporary signs, including A-frame sandwich boards on the sidewalk or public right-of-way, are not permitted. Window signs promoting the home business are also restricted in residential zones. A separate sign permit is generally not required for home occupation signs that meet these standards, but the property owner is responsible for compliance. Signs placed in the public right-of-way or on utility poles are prohibited countywide and are subject to removal. Rural-zoned properties may have slightly different rules, and historic district overlays can impose additional restrictions. Incorporated cities within King County (such as Redmond, Kirkland, Bellevue, and Seattle) maintain their own sign codes, which differ from county rules.