Sonoma County, CA Outdoor Lighting: Light Trespass & Shielding (2026)
Key Facts
- Fixture cap
- 1,000 lumens per fixture
- Off-site spillover cap
- 1.0 lux beyond property line
- Fixture design
- Fully shielded, downward-facing only
- Prohibited
- Floodlights and periphery placement
- Geographic reach
- LG/MTN combining zone only
Summary
Sonoma County caps exterior lighting only within the Taylor/Sonoma/Mayacamas Mountains scenic combining zone: fixtures must be shielded, downward-facing, capped at 1,000 lumens, and limited to 1.0 lux at the property line under Sec. 26-90-120(c)(2)(d), there is no countywide lighting ordinance.
Exterior lighting shall be downward facing, fully shielded, and located at the lowest possible point to the ground to prevent glare and light pollution. Light fixtures shall not be located at the periphery of the property and shall not spill over onto adjacent properties or into the night sky. Luminaires shall have a maximum output of 1000 lumens per fixture. Total illuminance beyond the property line created by simultaneous operation of all exterior lighting shall not exceed 1.0 lux.
Official source re-checked September 7, 2026: no newer edition of the code had been published (publisher’s edition: Code of Ordinances: Supplement 64 Update 2).
Full Breakdown
The county's only quantified exterior-lighting standard sits inside the Taylor/Sonoma/Mayacamas Mountains Local Guidelines combining zone (LG/MTN), covering hillside parcels visible from public roads. Under Sec. 26-90-120(c)(2)(d), fixtures must be downward-facing, fully shielded, and set as low as possible; they cannot sit at the property's periphery or spill onto neighbors or the night sky; output is capped at 1,000 lumens per fixture with illuminance beyond the property line held to 1.0 lux; floodlights are barred; and security lighting must be motion-sensor activated. Outside this zone, the county caps lighting only for specific uses, multifamily development, vacation rentals, homeless shelters, and cannabis operations, not general residential or commercial lighting.
Violations & Fines
Noncompliant lighting blocks Design and Site Plan Review approval and building permit issuance for MTN-zone development; the Board-appointed Citizen Advisory Committee and Permit and Resource Management Department enforce compliance through the standard zoning permit process.
Frequently Asked Questions
Does Sonoma County have a countywide light pollution ordinance?
What does the Taylor/Sonoma/Mayacamas Mountains lighting standard require?
Does this rule apply inside the City of Sonoma?
Sources & Official References
Other rules in Sonoma County
California rules heatmap·Compare Sonoma County to another location·View the California outdoor lighting overview
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