Sonoma County, CA Fire Regulations: Wildfire Zones (2026)

Chapter 13 of the Sonoma County Code (Fire Safety Ordinance 6396, adopted 2022) consolidates the County's wildland-urban interface (WUI) construction and access requirements. Under an agreement with CAL FIRE, Sonoma County serves as the local inspection authority and enforces SRA Fire Safe Regulations (14 CCR Sections 1270 et seq.) plus the County's parallel LRA standards. The CAL FIRE 2025 Fire Hazard Severity Zone maps - released February 24, 2025 - classify large portions of the county into Moderate, High, and Very High zones based on terrain, vegetation, fire history, and climate. Within any SRA parcel, or any LRA parcel mapped Very High, new structures and major remodels must comply with California Building Code Chapter 7A / California Residential Code Chapter 337, which require: Class A roofing (Sonoma County adopts a Class A-only standard - more restrictive than the state default); ember-resistant vents with corrosion-resistant 1/8-inch or finer mesh; non-combustible or ignition-resistant exterior wall cladding; dual-pane windows with at least one tempered pane; ignition-resistant decking materials; and 1-hour fire-resistive eaves. Driveways must meet width and grade standards for fire-apparatus access (typically 20 ft minimum unobstructed width on private roads serving more than one parcel, 10% grade for paved, 15% maximum for all-weather surfaces, with 50-foot turnouts and turnarounds for fire apparatus). Address signs must be 4 inches high in contrasting reflective color. Properties rebuilt after the 2017, 2019, and 2020 fires were required to meet the post-2008 Chapter 7A standards regardless of prior nonconforming status. The County does not publish its own SRA/LRA boundary map; owners should use the CAL FIRE FHSZ viewer.