Invasive Plant Rules in King County, WA (2026)

1 county-level rule, plus city-specific rules for 6 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.

Prohibited Species

Unincorporated King County treats any plant on Washington's official noxious weed list, WAC chapter 16-750, as a regulated noxious weed under county code, regardless of the list's regional designation, and funds enforcement through an annual per-parcel assessment.

King County Noxious Weed Rules

Some Restrictions

King County Code § 21A.06.815

Noxious weed: a plant species that is highly destructive, competitive or difficult to control by cultural or chemical practices, limited to any plant species listed on the state noxious weed list in chapter 16-750 WAC, regardless of the list's regional designation or classification of the species. (Ord. 15051 § 81, 2004: Ord. 10870 § 203, 1993). 21A.06.817 Off-street required parking lot....

Full ordinance details →Official source ↗