Loudoun County, VA Outdoor Lighting: Light Trespass (2026)

Loudoun County regulates light trespass primarily through Zoning Ordinance §5-652 performance standards — maximum illuminance at property lines: 0.1 foot-candle at residential property boundaries; 0.5 fc at commercial boundaries. Sources exceeding these levels create actionable light trespass. Enforcement path: residents complain to Loudoun County Department of Building and Development / Code Enforcement; inspector measures illuminance with calibrated photometer; notice of violation issued for non-compliance. Common scenarios in Loudoun: (1) unshielded security floodlights aimed at neighbors, especially in rural AR-1/A-3 areas where homes sit on large lots but property lines cross open fields; (2) commercial parking lot glare into adjacent residential neighborhoods (Route 7 corridor); (3) data center campus lighting spillover in Ashburn — typically well-controlled; (4) LED barn and farm work lights in Middleburg/Purcellville horse country disturbing equestrian evening operations. Holiday lighting has informal temporary exemptions but may draw complaints if extreme. Virginia nuisance law (common-law doctrine) supports civil actions when light interferes with reasonable use and enjoyment of property — remedies include injunctive relief and damages. HOAs (Brambleton, Broadlands, One Loudoun, Ashburn Village) frequently have covenant provisions stricter than county requiring shielded fixtures and limiting holiday light duration. Disputes often resolve through neighbor mediation via the Virginia Center for Restorative Justice or HOA channels before escalating to county enforcement. Commercial properties with chronic light trespass face permit renewal scrutiny.