District of Columbia, DC Outdoor Lighting: Dark Sky Rules (2026)

DC does not have a dedicated 'dark sky ordinance' like Flagstaff or Tucson, but multiple regulations combine to control outdoor lighting. The DC Energy Conservation Code (adopted from the International Energy Conservation Code with amendments at 12-I DCMR) regulates exterior lighting power density, controls, and shielding for commercial buildings. Section C405 requires automatic shutoff controls, limits exterior lighting power to prescribed densities (watts per linear foot of building facade or watts per square foot of lit area), and mandates BUG rating (Backlight-Uplight-Glare) compliance so that fixtures minimize sky glow. Residential lighting is largely unregulated at the fixture level but is subject to the general nuisance/trespass provisions in DCMR 14-802 and DC Code 22-1321. DDOT's Public Realm Design Manual specifies shielded full-cutoff LED fixtures at 3000K (warm) correlated color temperature for new street lighting, with Ward 3 conservation zones using 2700K in historic districts. A multi-year citywide streetlight modernization project (the DC Smart Street Lighting Project) is replacing legacy high-pressure sodium lamps with networked LED fixtures. The National Park Service controls lighting on federal parkland, and the Secretary of the Interior's Standards influence lighting in historic districts like Georgetown, where period-appropriate fixtures are required. Advisory Neighborhood Commissions weigh in on specific new developments. DC is not an International Dark-Sky Association certified community, but the trajectory of its public lighting is in alignment with dark-sky principles.