Ada County, ID Outdoor Lighting: Billboard Lighting (2026)

Section 8-3-12(K)(6) of the County Code addresses billboard illumination directly: billboards may be illuminated in compliance with Section 8-3-8 (Lighting) of this Chapter, and any other applicable ordinances, but no flashing or intermittent lighting of billboards is permitted. That cross-reference pulls in the full outdoor lighting chapter, Section 8-3-8, which Ada County adopted to conserve energy, control glare and prevent nuisance lighting without cutting into safety or security. Under subsection D, changing colors, moving lights, and searchlights used for advertising are prohibited outright in every district, laser sources and mercury vapor fixtures are banned, and no billboard or tower lighting may exceed the applicable district height limit except where FAA rules require it.

Subsection F sets graduated shielding requirements by output: any fixture of 260 lumens or more needs an opaque top to block up-lighting, fixtures of 1,000 lumens or more must also keep the bulb concealed, and any fixture of 1,800 lumens or more needs a full cutoff shield as illustrated in Figure 8-3-8-1. Floodlight fixtures, which many illuminated billboards use to wash the face of the sign, cannot tilt more than 45 degrees from vertical and must be aimed to avoid direct glare into a roadway or onto abutting property.

Freestanding fixture height is capped at 25 feet or the height of the principal structure, whichever is less. A lighting plan showing fixture location, height, shielding and photometric detail is required as part of any master site plan review, and the Director of Development Services can approve routine lighting plans administratively under Section 8-9-4(C)(6).