Richland, WA Outdoor Lighting: Light Trespass & Shielding (2026)

RMC § 23.58.020 defines light trespass as the shining of light produced by a luminaire beyond the boundaries of the property on which it is located, and the chapter's operative response is the Good Neighbor shielding rule at RMC § 23.58.030(B): every outdoor light fixture must be shielded so that light is directed downward and the direct line of sight to the fixture's lamp is limited to the property where the fixture is installed, unless the fixture falls within an exclusion listed at RMC § 23.58.050.

That exclusion list matters for a light-trespass complaint because it removes several common sources from the shielding duty: fixtures already installed before the ordinance's effective date, private residential lighting under 1,800 lumens, motion-sensor security lights that stay on 10 minutes or less, and gas-combustion or neon-tube light sources. Outside those exclusions, RMC § 23.58.030(C) additionally caps light-pole height at the height of the nearest streetlight and RMC § 23.58.030(D) folds parking-area lighting into the same shielding standard, so a business or apartment complex cannot point unshielded pole lights or lot lights across a property line into a residential yard.

RMC § 23.58.040(B) backs the shielding rule with a separate prohibition: outside illumination of any building, public or private, by floodlight projected above the horizontal is unlawful between midnight and sunrise, with an exception only for required emergency lighting by a public agency. Development Services and the zoning administrator enforce the chapter, and RMC § 23.58.070 requires any enforcement action for a light-trespass violation to be commenced within one year of the date the violation occurred.