Washington, DC Outdoor Lighting: Light Trespass & Shielding (2026)

Subtitle U, § 804 of the Zoning Regulations of 2016 sets external-effects standards for any use established in a PDR zone that isn't allowed in a non-PDR zone, plus uses accessory to it. 6 is the light-trespass clause: it bars any direct or reflected glare or heat from any source, whether a floodlight, outdoor operation, or industrial process, from being 'detectable in objectionable amounts' once it crosses the boundary of the zone district where the use operates. 9 separately requires back-up generators to be fully enclosed in the principal structure or sited at least 200 feet from residentially zoned land.

An applicant for a building permit or certificate of occupancy for a § 804-covered use must file a site plan and supporting materials with the Department of Consumer and Regulatory Affairs under § 805 showing how the use will meet these standards before occupancy is approved. Because the rule is boundary-based rather than a fixed lumens or footcandle cap, enforcement turns on whether glare or heat is objectionably detectable at the property line of the zone, a case-by-case standard the Zoning Administrator and DCRA apply during permit review and complaint follow-up.