Gaithersburg, MD Outdoor Lighting: Light Trespass (2026)

Light trespass in Gaithersburg is regulated through a combination of the city zoning ordinance, site plan review requirements, and general nuisance provisions. For new commercial and multi-family development, photometric plans must demonstrate that illumination at the property boundary does not exceed 0.5 footcandles when adjacent to residential uses. Light fixtures must be aimed and shielded so the light source is not directly visible from neighboring residential properties. Existing properties that install new lighting creating a documented nuisance may be subject to code enforcement under the city's general nuisance provisions. Montgomery County Code Chapter 31B (Noise Control) and nuisance provisions in Chapter 31C can also apply to excessive light as an environmental nuisance in unincorporated areas bordering Gaithersburg. Residents experiencing light trespass should first attempt to resolve the issue directly with the neighbor. If that fails, a complaint can be filed with Gaithersburg Code Enforcement at 301-258-6330. The city may require the offending property owner to redirect, shield, or remove the light source. Security lighting and motion-activated floodlights are common sources of light trespass complaints, and the city may require these to be properly aimed downward and away from neighboring windows.