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

Section 12.E.2 of the Jefferson County Zoning Resolution states that luminaires and their supporting structure shall be wholly confined to the property, directly addressing light trespass onto neighbors. Section 12.E.5 sets maximum illumination measured at the property line by use: for example, residential, active-recreational, and agricultural uses adjacent to similar uses and rights-of-way may not exceed 0.2 foot-candles in the mountains or 0.3 in the plains, and any use adjacent to passive-recreational uses is capped at 0.1 foot-candles. Illumination is measured in foot-candles with the sensor horizontal at ground level, summing all on-site lighting including sign lighting and spillage from inside buildings.