DuPage County, IL Outdoor Lighting: Billboard Lighting (2026)

4. The rule has two independent triggers: illumination cannot be reflected outside the boundary of the zoning lot where the sign sits, and separately it cannot be reflected more than 10 feet above grade, so a billboard lit from below with floodlights cannot throw light past either boundary. Light itself has to be diffused or indirect rather than exposed bulbs or a glaring point source. This general sign-lighting rule sits alongside, but is distinct from, the electronic-display brightness ceiling in Section 37-1103(C), which sets numeric nit limits of 5,000 nits by day and 500 nits from dusk to dawn for LED and digital billboards specifically; a static, externally floodlit billboard has to meet the diffusion and reflection limits of (A)(15) even though it is not an electronic display and the nit ceiling in (C) does not apply to it.

Sign permits are issued by the DuPage County Building Department, and a plan showing the proposed fixture type, aim and shielding has to demonstrate compliance with the diffusion and reflection limits before a permit for an illuminated sign or billboard is approved.