Douglas County, CO Outdoor Lighting: Dark Sky Rules (2026)
Key Facts
- Fixture standard
- Full cutoff required
- Prohibited
- Strobe, searchlight, skyward light
- Residential lumen guide
- 2,400 lumens unless shielded
- Purpose
- Protect night-sky viewing
- Governing section
- DCZR Section 30
Summary
Douglas County's lighting standards protect the night sky by requiring most outdoor fixtures to be full cutoff, so no light shines at or above horizontal. Blinking, strobe, searchlight, and skyward-oriented lighting is prohibited, and single-family homes should keep fixtures under 2,400 lumens unless shielded.
Light fixtures, except as otherwise permitted herein, are required to be full cutoff as defined by the Illuminating Engineers Society of North America (IESNA). Full cutoff light fixtures result in a light distribution pattern where no light is permitted at or above a horizontal plane at the bottom of the fixture.
Full Breakdown
Section 30 of the Zoning Resolution sets outdoor lighting standards to protect the public's ability to view the night sky and reduce glare, light pollution, and light trespass. Section 3005.01 requires light fixtures to be full cutoff, producing a distribution where no light is emitted at or above a horizontal plane at the bottom of the fixture. Section 3004 prohibits blinking or flashing lights, strobe lights, searchlights, beacons, laser light, and other upward or outward oriented lighting. For single-family residential and agricultural areas, Section 3005.16 recommends limiting fixtures to 2,400 lumens unless shielded and using motion sensors for security lighting.
Violations & Fines
Non-conforming commercial lighting can be cited during site plan review or on complaint and ordered corrected; residential fixtures are largely exempt but still may not create disability glare.
Frequently Asked Questions
Are searchlights or strobe lights allowed?
Do the dark-sky rules apply to my house?
Sources & Official References
Other rules in Douglas County
Compare Douglas County to another location·View the Colorado outdoor lighting overview
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