Sonoma County, CA Outdoor Lighting: Dark Sky Rules (2026)
Key Facts
- Max fixture output
- 1,000 lumens per fixture
- Max spillover
- 1.0 lux beyond property line
- Zone scope
- LG/MTN combining zone only
- Floodlights
- Prohibited outright
- Security lighting
- Motion-sensor activation only
Summary
In the Taylor/Sonoma/Mayacamas Mountains scenic combining zone, exterior lighting on new homes and structures must be downward-facing, fully shielded, capped at 1,000 lumens per fixture, and limited to 1.0 lux beyond the property line.
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
Sonoma County Code § 26-90-120 sets the county's most detailed outdoor lighting standard, but it only applies within the LG/MTN combining zone covering the Taylor, Sonoma and Mayacamas Mountains scenic landscape units. New single-family dwellings and appurtenant structures there must use downward-facing, fully shielded fixtures capped at 1,000 lumens per fixture, capped at 1.0 lux total illuminance beyond the property line, no floodlights, and motion-sensor-only security lighting; roadway, parking and driveway lights must be low-profile, full cut-off fixtures. A separate, nearly identical lighting-plan requirement applies countywide to licensed vacation rentals under § 4-205.C. Outside these two contexts, unincorporated Sonoma County does not otherwise regulate residential exterior lighting.
Violations & Fines
Enforced as a condition of the Design Review or Administrative Design Review permit for the parcel; noncompliant exterior lighting can trigger code enforcement action, a required retrofit, or revocation of the design review approval.
Frequently Asked Questions
Does this dark-sky rule apply to my whole property in Sonoma County?
What's the maximum brightness allowed for outdoor fixtures?
Can I install security floodlights on my property?
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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