Outdoor Lighting in King County, WA (2026)

3 county-level rules, 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.

Dark Sky Rules

In the North Highline/White Center design-standards area of unincorporated King County, new and substantially improved buildings must minimize night-sky illumination and use fully shielded fixtures that block all direct uplight.

King County Outdoor Lighting Shielding Rules

Some Restrictions

King County Code § 21A.09.100

A. Lighting design shall promote public safety, encourage visibility throughout the entire site, consider a mature landscape, and minimize light spillover to adjacent properties and illumination of the night sky. B. All public areas shall be illuminated at the following levels: 1. Building entries shall have up to three foot-candles; 2. Sidewalks and walkways shall have between one-h...

Full ordinance details →Official source ↗

Light Trespass & Shielding

In unincorporated King County's North Highline design-review area, new commercial and multifamily buildings must aim exterior lights onto the building or adjoining ground, capping illumination at the property line at one foot-candle.

King County Light Trespass Cap (North Highline Only)

Some Restrictions

King County Code § 21A.09.100.D

All building lights shall be directed onto the building itself or the ground immediately adjoining the building. Illumination at the property line shall be a maximum of one foot-candle. E. Parking lot lighting fixtures shall be nonglare and mounted no more than fifteen feet above the ground. F. All lighting fixtures shall be fully shielded, where a solid barrier at the top of the fixture i...

Full ordinance details →Official source ↗

Billboard Lighting

Unincorporated King County allows billboards to be illuminated, but light sources must sit no farther from the sign than its height and can't shine directly into homes or streets.

King County Billboard Sign Illumination Rules

Some Restrictions

King County Code § 21A.20.060(F)

F. Regarding sign illumination and glare: 1. Except as otherwise provided in this chapter, all signs may be illuminated; 2. The light source for indirectly illuminated signs shall be no farther away from the sign than the height of the sign; 3. Indirectly and directly illuminated signs shall be arranged so that no direct rays of light are projected from such artificial source into ...

Full ordinance details →Official source ↗