Lower Merion, PA Outdoor Lighting: Dark Sky Rules (2026)

Article III of Chapter 105 imposes Township-wide outdoor lighting standards. Section 105-12.A requires that all outdoor lighting be selected, located, and focused so that only the building, structure, sign, or other open area on the lot is illuminated, and that it be aimed and/or shielded so light is not directed onto any adjacent lot, public street, or public right-of-way. Section 105-12.B(1) goes further for the highest-impact fixtures: any luminaire lighting a parking area, driveway, sidewalk, walkway, or other hardscape surface not covered by a special approval or permit must have an uplight value of zero, with no light emitted above 90 degrees, the horizontal plane.

The article's definitions in Section 105-11 back this with a technical benchmark: a FULLY SHIELDED LUMINAIRE is one built and installed so all emitted light, whether direct or reflected, is projected below the horizontal plane through the fixture's lowest light-emitting part, a definition the Township ties explicitly to International Dark Sky Association practice. New lighting must comply immediately; existing lighting is grandfathered until a property changes use, undertakes a major addition or renovation (25% or more of dwelling units, floor area, seating, parking, or luminaires), or resumes use after a vacancy of six months or more, at which point it must be brought into compliance under Section 105-12.B(2).

Compliance is checked at the building-permit stage through the lighting submission requirements in Section 105-12.C, and the Department of Building and Planning can require a full Major Lighting Submission, including a photometric plot plan, where conditions warrant it.