Home Business in King County, WA (2026)

4 county-level rules, plus city-specific rules for 8 cities in King County, Washington.

Verified from official government sources

Note: These county rules apply to unincorporated areas of King County. If you live within an incorporated city, that city's own rules apply: see the city list below.

Zoning & Home Occupation Permits

Unincorporated King County caps home businesses at 20% of a dwelling's floor area and one on-site nonresident employee in residential and commercial zones.

King County Home Occupation Zoning Rules

Some Restrictions

King County Code § 21A.30.080

In the R, UR, NB, CB, and RB zones, residents of a dwelling unit may conduct one or more home occupations as accessory activities, as follows: A. The total floor area of the dwelling unit devoted to all home occupations shall not exceed twenty percent of the floor area of the dwelling unit... No more than one nonresident employee shall be allowed to work on-site for the home occupation or occup...

Full ordinance details →Official source ↗

Signage Rules

Unincorporated King County caps home occupation and home industry signs at one nonilluminated wall sign, no bigger than 10% of the facade it's mounted on.

King County home business sign limits

Some Restrictions

King County Code § 21A.20.080(B)(3)

3. Home occupation and home industry signs are limited to: a. one nonilluminated wall sign not exceeding ten percent of the building façade on which they are located; and b. in the RA zone, one nonilluminated freestanding sign not exceeding twenty-four square feet and a maximum height of six feet. (Ord. 16950 § 21, 2010: Ord. 16594 § 4, 2009: Ord. 16267 § 37, 2008: Ord. 15404 §...

Full ordinance details →Official source ↗

Customer Traffic Restrictions

Home occupations in unincorporated King County's R, UR, NB, CB, and RB zones may host customer visits and deliveries only 8 a.m.-7 p.m. on weekdays and 9 a.m.-5 p.m. on weekends, and can't add more than four extra vehicle trips at any given time.

King County Home Business Client Visit Hours

Some Restrictions

King County Code § 21A.30.080(K), (L)

K. ...on average increase vehicular traffic by more than four additional vehicles at any given time; L. Customer visits and deliveries shall be limited to 8:00 a.m. to 7:00 p.m. on weekdays, and 9:00 a.m. to 5:00 p.m. on weekends; and

Full ordinance details →Official source ↗

Home Daycare

King County's zoning code classifies in-home child care by headcount: up to 12 people in a 24-hour period is "Daycare I," a separate land-use category from home occupations, while any home caring for more than 12 becomes "Daycare II."

King County Home Daycare Zoning Class

Some Restrictions

King County Code § 21A.06.265

Daycare: an establishment for group care of non-resident adults or children. A. Daycare shall include only, SIC Industry No. 835, Child Day Care Services, SIC Industry No. 8322, Adult Daycare Centers and the following: 1.Adult Daycare, such as adult day health centers or social day care as defined by the Washington State Department of Social and Health Services; 2. Nursery schools for...

Full ordinance details →Official source ↗