Arapahoe County, CO Outdoor Lighting: Light Trespass & Shielding (2026)
Key Facts
- Non-residential cap
- 0.3 foot-candles at property line
- Residential cap
- 0.1 foot-candles at property line
- Measured at
- 5.5 ft above grade, line of sight
- Waiver authority
- Planning Division Manager
- SFD homes
- exempt from most rules, not this one
Summary
Arapahoe County limits how much light can spill onto a neighboring lot: measured at the property line, 5.5 feet above grade, aimed in a direct line of sight to the brightest fixture visible from that point, illuminance cannot exceed 0.3 foot-candles where the adjoining land is non-residential or 0.1 foot-candles where it is residential. PWD staff can require a line-of-sight analysis, and the Planning Division Manager may waive the standard if no residential use abuts the site.
PWD staff may request an analysis of line-of-sight on a case-by-case basis dependent on site conditions. The maximum initial line-of-sight illuminance is measured at the property line, measured five and one-half feet above grade aimed in a direct line of sight to the brightest light fixture visible from such point, shall not exceed 0.3 foot candles for non-residential or 0.1 foot candles on residential properties. The Planning Division Manager may waive this requirement if there are no residential uses abutting the subject site and/or the light trespass does not reach the property zoned or used for residential purposes at the time the light fixture is installed.
Full Breakdown
6 of the Land Development Code, which opens by declaring that no person shall install or maintain any exterior lighting that fails to meet the requirements of the section. It sits alongside a companion rule requiring any fixture that emits more than 900 lumens to be fully shielded from view of adjacent properties and public rights-of-way, and a 10-foot-candle cap on illuminance from buildings and signage. 5 feet above grade, aimed directly at whichever light fixture is brightest from that vantage, not an average across the yard.
6 states these lighting standards reach all exterior lighting, including illumination from outdoor signs, and bind any use that needed county approval of a General Development Plan, Specific Development Plan, Administrative Site Plan or Use by Special Review. Single-family detached homes are otherwise excused from most of this chapter, but the code specifically pulls them back in for glare and light trespass, new SFD lighting and any replacement lighting must still meet the property-line illuminance caps, unless the home sits on 100 or more acres zoned A-E or A-1, which is fully exempt.
The Chapter 7 definition of 'Light Trespass' backs this standard up in plain language: light falling where it is not wanted or needed, including light projected onto a property from a source not located on that property.
Violations & Fines
Installing or maintaining exterior lighting that exceeds the 0.3/0.1 foot-candle line-of-sight caps, or that skips the required shielding above 900 lumens, violates LDC § 4-1.6's design standards, which state flatly that no person may maintain non-conforming exterior lighting. Compliance is checked at final inspection for the building permit covering the fixture, and PWD/Planning Division staff can require a line-of-sight analysis and order correction of an offending fixture.
Frequently Asked Questions
How much light can cross onto my neighbor's property in unincorporated Arapahoe County?
Does my single-family home have to follow the light trespass rule?
Can the county waive the light trespass limit?
Sources & Official References
Other rules in Arapahoe County
Compare Arapahoe County to another location·View the Colorado outdoor lighting overview
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