Boulder, CO Outdoor Lighting: Light Trespass & Shielding (2026)

Section 9-9-16(d)(1) of the Land Use Code measures light trespass at the property line itself. In or adjacent to a residential zone, no fixture may push more than 0.1 footcandles across that line; in nonresidential zones the ceiling rises to 0.2 footcandles. A narrow exception applies to a building within five feet of a public right-of-way or sidewalk, where the pedestrian-area light levels set in subsection (e) control instead, capped in every case at 0.2 footcandles measured at the curbline. In a nonresidential district, the city manager can approve light levels above 0.2 footcandles at the property line only after finding the increase will not adversely affect an adjacent owner, evidence for which can include a statement from that owner.

Subsection (d)(7) adds a design rule for any fixture within ten feet of a property line, a residential zoning district, an existing residential use, or a public right-of-way: it must be aimed away from that boundary, classified as an IESNA Type III or Type IV fixture (both of which throw light forward rather than sideways), and shielded on the side closest to the property line, residential zone, residential use or right-of-way. Building-facade lighting that is measurable at ground level counts toward the same property-line maximum. The city manager can grant a variance under Section 9-9-16 in combination with Section 9-2-3, and a denial can be appealed to the Board of Zoning Adjustment and Building Appeals.