Exterior lighting and light trespass across the DC area
How bright can outdoor lights be, and can they shine on a neighbor? The rules differ at every jurisdiction line. Here is the short answer for each.
Disclaimer: This is general information, not legal or professional advice for any one property. Codes change. SetbackIQ is not a zoning determination, a permit, or a survey, and it does not replace an architect, engineer, or lawyer. Confirm with your building and zoning offices before you build, buy, or sign a contract.
| Where | Short answer |
|---|---|
| Washington, DC | No DC rule limits light from a house or townhouse onto a neighbor's lot. DC's only light-trespass rules (Green Construction Code § 409: shielding, glare limits, 3000 K maximum) apply to new buildings and major renovations of 10,000 sq ft or more, and the code expressly excludes one- and two-family houses and townhouses up to three stories. A neighbor's glare is a civil nuisance matter or one for mediation. |
| Montgomery County, MD | On-site lighting must measure 0.5 footcandles or less at the lot line, with full or partial cutoff fixtures. |
| Prince George's County, MD | Subtitle 27-6700 sets exterior lighting standards. Motion-sensor security lights that shut off within 15 minutes and pool underwater lights are exempt. |
| Alexandria, VA | Alexandria's zoning ordinance sets no light-trespass limit for houses. Lighting standards come through site plans and, in the historic districts, BAR review. |
| Arlington County, VA | The zoning ordinance sets no general light-trespass limit for houses. Private pool lighting must be arranged and hooded so all direct light stays on your property. |
| Fairfax County, VA | Fairfax's outdoor lighting rules apply to houses with some relief: small fixtures (1,500 lumens or less) skip the full cut-off rule, and motion lights up to 4,000 lumens are exempt if they shut off within 5 minutes and stay aimed on your property. No fixture may cause disability glare. |
Towns and cities inside these counties (for example, Rockville, Gaithersburg, Bowie, Laurel, Herndon, Vienna, and Falls Church) have their own rules.