Glenn County, CA Outdoor Lighting: Light Trespass (2026)

Light trespass - light from one property spilling onto another - is controlled in unincorporated Glenn County by the glare performance standard in Section 15.560.080 (Glare and Heat) of the Unified Development Code. The standard states that 'All exterior lighting accessory to any use shall be hooded, shielded or opaque' and that 'No unobstructed beam of light shall be directed beyond any exterior lot line,' with buildings and structures under construction exempt. Because these are 'performance standards,' Section 15.560.020(B) provides that any required measurements are made at the exterior lot lines, which is the relevant boundary for evaluating spillover light. Section 15.560.010 frames the purpose of the chapter as promoting compatibility among land uses, protecting the rural-agricultural character of the county, and controlling nuisances. The county's review authority may impose more restrictive lighting conditions as part of a discretionary permit (Section 15.560.030(C)). For lighted signs, Section 15.620.060(C)(6) separately requires that sign lighting not produce glare on other properties and that the light source not be visible from adjacent property or a public street. Glenn County does not set numeric footcandle limits at the property line, so the operative test is whether exterior lighting is fully shielded and whether any unobstructed beam crosses your lot line. Persistent light spillover may also be addressed as a nuisance; direct questions to Glenn County Planning & Community Development Services Code Enforcement.