Arapahoe County, CO Outdoor Lighting: Dark Sky Rules (2026)
Key Facts
- Shielding threshold
- Lamps over 900 lumens
- Enforcing agency
- Arapahoe County PWD Planning Division
- Ornamental exemption
- ≤15W/100 lumens, off midnight-dusk
- Residential string lights
- Fully exempt from chapter
- Large-parcel exemption
- 100+ acre A-E/A-1 SFD exempt
- Standard
- IESNA full cut-off shielding
Summary
In unincorporated Arapahoe County, any outdoor light fixture emitting more than 900 lumens must be fully shielded from view of neighboring properties and public rights-of-way under the Land Development Code's lighting standards. Fixtures must meet IESNA full cut-off mounting standards, checked before final building-permit inspection.
The illumination from a lamp that emits more than 900 lumens shall be fully shielded from view from adjacent properties and public right-of-ways, except as otherwise permitted herein. Fixtures shall meet the IES standards for fully shielding, full cut-off and mounting of fixtures.
Full Breakdown
6) states its intent is to reduce light pollution, light trespass, glare, sky glow and offensive light sources, prevent poorly designed outdoor lighting, and protect wildlife habitat at night. The standards apply to all exterior lighting, including illumination from signs, on any use requiring a General Development Plan, Specific Development Plan, Administrative Site Plan or Use by Special Review approval, and compliance is confirmed before final building-permit inspection. 1, requires any lamp over 900 lumens to be fully shielded from adjoining properties and rights-of-way and to meet IESNA full cut-off standards.
§24-82-902. Single-family detached homes are largely excused too, apart from having to replace or shield failed unshielded mercury-vapor fixtures and meet the separate glare/light-trespass limits; homes on 100-plus-acre A-E or A-1 parcels are fully exempt. Where a nonconforming fixture is removed, its replacement must be a shielded, conforming fixture, and a burned-out lamp must be replaced with a conforming one.
Violations & Fines
Noncompliant fixtures block final building-permit inspection until they're shielded or replaced, and a removed nonconforming fixture can only be replaced with a conforming, shielded one. Arapahoe County's Planning Division Manager enforces the standard and may grant a formal Exception under §4-1.6.D only on a finding of unique circumstances, minimal deviation, and consistency with the chapter's purpose: there is no self-help variance.
Frequently Asked Questions
Do I need to shield floodlights on my unincorporated Arapahoe County property?
Are single-family homes exempt from the county's lighting rules?
Who enforces the shielding requirement and can I get an exception?
Sources & Official References
Other rules in Arapahoe County
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