Sonoma County, CA Fire Regulations: Wildfire Zones (2026)
Key Facts
- Zone framework
- CAL FIRE FHSZ: Moderate / High / Very High
- Responsibility areas
- SRA (state) and LRA (local)
- New LRA Very High (2025)
- Thousands of acres added
- Building standard
- CA Building Code Chapter 7A / CRC 337
- Fire protection plan
- Required in SRA/High/Very High
- Major fires
- Tubbs 2017, Kincade 2019, Glass 2020
Summary
Much of unincorporated Sonoma County lies within Fire Hazard Severity Zones, including State Responsibility Area and Very High zones, reflecting catastrophic fires like Tubbs (2017), Kincade (2019), and Glass (2020). New construction in WUI/SRA and Very High zones must meet ignition-resistant standards under California Building Code Chapter 7A, and SRA/Very High projects require a fire protection plan reviewed before permit issuance.
4905.4 Setbacks for Structure Defensible Space. Except where more restrictive requirements apply, construction, projections, openings and penetrations of exterior walls of buildings constructed on parcels within State Responsibility Areas (SRA) shall provide setbacks from the property line and/or exterior wall protection according to table 4905.4(a) or table 4905.4(b), in accordance with California Code of Regulations, Title 14, SRA Fire Safe Regulations.
Full Breakdown
Sonoma County's wildfire risk is mapped through CAL FIRE's Fire Hazard Severity Zones (FHSZ), which classify land as Moderate, High, or Very High in both the State Responsibility Area (SRA) and Local Responsibility Area (LRA). The County's exposure is severe: the 2017 Tubbs Fire, 2019 Kincade Fire, and 2020 Glass Fire each caused major loss of life and property. Under the updated 2025 CAL FIRE maps, unincorporated Sonoma County added thousands of acres of newly designated Very High fire hazard zone in the LRA, on top of extensive SRA Very High areas.
New structures in a Wildland Urban Interface (WUI) or State Responsibility Area location must comply with ignition-resistant construction standards in 'Chapter 7A, in the California Building Code and Chapter 337 in the California Residential Code,' which require Class A roofing, ember-resistant venting, fire-resistant exterior coverings, windows, decking, and accessory-structure standards. Construction projects and new subdivisions in the SRA and in High or Very High Fire Severity Zones must have a detailed fire protection plan reviewed by Permit Sonoma's Fire Prevention Division before a building permit is issued.
These building requirements work alongside the year-round defensible-space duties in County Code Chapter 13A. Sonoma County notes it does not maintain an official SRA mapping site; property owners can confirm SRA status through CAL FIRE's State Responsibility Area Map Viewer by address.
Violations & Fines
Building in a WUI/SRA or Very High Fire Hazard Severity Zone without meeting California Building Code Chapter 7A ignition-resistant standards, or proceeding without the required fire protection plan in SRA/High/Very High zones, will prevent permit issuance and final approval through Permit Sonoma.
Frequently Asked Questions
How do I know if my property is in a Sonoma County fire hazard zone?
What building rules apply if I build in a Very High fire zone?
Sources & Official References
Other rules in Sonoma County
California rules heatmap·Compare Sonoma County to another location·View the California fire regulations overview
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