St. Charles County, MO Outdoor Lighting: Light Trespass & Shielding (2026)

The section works as two separate tests, and a fixture in St. Charles County has to pass both. The first is about aim. In no instance may an exterior lighting fixture be oriented so that the lighting element, or a transparent shield over it, is directed to an adjacent property located within a residential zoning district. Notice what the ordinance actually measures there. It looks at the zoning of the property receiving the light, so a fixture on a commercial, institutional or industrial site is judged by whether the lot next to it is zoned residential, and it treats a transparent shield as part of the problem rather than the cure, because a clear cover still points the source at the neighbor.

50 foot-candles. 50. The ordinance names its own preferred fix for both problems, encouraging shielded luminaries and careful fixture placement rather than simply forbidding bright light. Mounting height is limited as well: pole-mounted fixtures cannot exceed 20 feet or the height of the building they light, whichever is shorter, so a taller pole cannot be used to push light further across a St. Charles County lot line. A few categories sit outside all of this. Government security lighting on public buildings, holiday lighting, and right-of-way and traffic lighting are exempted.