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Seattle, WA Outdoor Lighting: Billboard Lighting (2026)

Some Restrictions
Compiled from the official code textEditor Martyn O'NeillLast verified September 2026

Key Facts

Governing section
SMC 23.55.014(E)(3)
Incandescent light cap
1.25 watts per sq ft of sign area
Fluorescent/other light cap
1 watt per sq ft of sign area
Chasing/message-board lights
prohibited outright
Unregistered sign face penalty
$5,000 per sign face annually
Registration deadline
filed with SDCI Director by July 1

Summary

SMC 23.55.014(E)(3) caps how brightly Seattle billboards and other off-premises signs can be lit: incandescent illumination is limited to 1.25 watts per square foot of sign area, fluorescent or other illumination to 1 watt per square foot, and signs that use lights as part of the advertising message itself, chasing displays or message boards, are banned outright.

3.Lighting. No off-premises sign shall be incandescently illuminated by more than one and one-quarter (1¼) watts of electrical power per square foot of sign area, or be fluorescently or otherwise illuminated by more than one (1) watt of electrical power per square foot of sign area. Off-premises signs that include lights as part of the message or content of the sign (chasing and message board advertising signs) are prohibited.

View official code

Official source re-checked September 7, 2026: no newer edition of the code had been published (publisher’s edition: Municipal Code: Supplement 44 Update 1).

Full Breakdown

014's "Development Standards Applicable to All Off-premises Signs," alongside dispersion spacing between billboard structures, a roof-sign ban, and height caps of 40 feet outside industrial zones (65 feet inside them). 25 watts per square foot of sign face while fluorescent or any other lighting method caps out at 1 watt per square foot. Separately, subsection A prohibits relocating or reconstructing an advertising sign unless the existing sign was lawfully erected and registered, and any relocated sign face still can't increase in size. 010 per sign face, and display the SDCI-assigned registration number in figures at least 8 inches tall on the sign frame. Maintaining a sign face that isn't registered is unlawful under this section regardless of whether the lighting itself complies.

Violations & Fines

An off-premises sign lit beyond the incandescent or fluorescent wattage cap, or using prohibited chasing or message-board lighting, is a Title 23 violation subject to a notice of violation and the standard civil penalty under SMC 23.90.018.A: up to $150 per day for the first ten days of noncompliance, then up to $500 per day until the lighting is brought into compliance. Separately, maintaining any unregistered off-premises sign face carries an explicit annual civil penalty of $5,000 per sign face under subsection F, regardless of whether the sign is illuminated.

Frequently Asked Questions

How bright can a billboard be lit in Seattle?
SMC 23.55.014(E)(3) limits incandescent lighting to 1.25 watts per square foot of sign area and fluorescent or other lighting to 1 watt per square foot; signs cannot use lights as part of the advertised message, so chasing lights and message-board advertising signs are prohibited outright.
Are LED billboards regulated differently?
The wattage cap applies regardless of lighting technology. Video display signs are separately governed by SMC 23.55.005, which caps brightness at 500 nits between dusk and dawn and limits video display to on-premises signs outside residential, NC1, and NC2 zones.
What happens if a billboard owner doesn't register its sign faces?
SDCI assigns a registration number that must be displayed in 8-inch figures on the billboard frame; maintaining an unregistered sign face is unlawful and draws a $5,000 annual civil penalty per sign face under subsection F of SMC 23.55.014.

Sources & Official References

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