Marin County, CA Outdoor Lighting: Light Trespass & Shielding (2026)

Chapter 22.16 (General Development Standards) applies, by its own Section 22.16.020, to any proposed development that requires Master Plan, Design Review, or Site Plan Review approval, in addition to whatever other Development Code provisions govern the site. Section 22.16.030 lays out the general standards that apply within that review, and Subsection G addresses exterior lighting directly: 'Exterior lighting visible from off-site should be allowed for safety purposes only, shall consist of low-wattage fixtures, and should be directed downward and shielded to prevent adverse lighting impacts on nearby properties, subject to the approval of the Director.'

That standard functions as Marin County's general light-trespass rule for reviewed development: it bars decorative or high-intensity lighting that spills onto neighboring parcels, requires shielding and downward direction so the light source itself is not visible off-site, and puts approval of any exterior fixture in the Director's hands as part of the underlying permit. The companion finding in Section 22.42.060(C), used when the Review Authority decides a Design Review application, requires that a project's site layout and design 'will not eliminate significant sun and light exposure or result in light pollution and glare' on adjacent properties before it can be approved.

Because these are review-stage standards rather than a stand-alone lighting code, they attach to projects going through Master Plan, Design Review, or Site Plan Review, such as new residences, additions, and commercial development, rather than to every existing fixture countywide. A resident whose neighbor's newly permitted exterior lighting spills glare onto their property can raise the shielding and downward-direction requirement of Section 22.16.030(G) during that review or as a code-compliance complaint after installation.