Solano County, CA Outdoor Lighting: Dark Sky Rules (2026)

Solano County does not have a single, comprehensive dark-sky ordinance for unincorporated areas. Lighting controls instead appear as use-specific performance standards woven through Chapter 28 (Zoning Regulations). For several land uses, the code requires exterior lighting to be 'directional lighting that directs the light downward and inward toward the project site so as not to create a nuisance to neighbors.' For event and assembly uses, the code requires that lighting used during events 'shall be downcast and shielded so that neither the lamp nor the reflector interior surface is visible from any off-site location.' More broadly, the code's general standards call for lighting capable of providing adequate illumination for security and safety that is directed away from adjacent properties and public rights-of-way to prevent offensive light or glare. The county's performance standards also prohibit glint or glare detectable beyond any property line or by overflying aircraft. Together these rules push toward shielded, downward-directed fixtures that limit skyglow and spillover, the practical goals of dark-sky design, but they are applied through individual project review rather than a uniform lumens-or-Kelvin standard. For project-specific lighting requirements, consult the Planning Division (707-784-6765).