San Bernardino County, CA Fire Regulations: Wildfire Zones (2026)

San Bernardino County faces extreme wildfire exposure across the San Bernardino Mountains, valley foothills, and desert margins. The California Office of the State Fire Marshal designates Fire Hazard Severity Zones (FHSZ) using three levels: Moderate, High, and Very High. On June 10, 2025, the San Bernardino County Board of Supervisors adopted Ordinance No. 4489 designating the Fire Hazard Severity Zones in the Local Responsibility Areas of the San Bernardino County Fire Protection District, matching the State Fire Marshal's updated maps; state law allows the District to increase but not decrease the State's hazard designations.

FHSZ ratings reflect ignition likelihood, fire behavior under extreme weather, historical fires, vegetation type, terrain (hills and canyons), and ember intrusion from nearby wildlands. Consequences of a mapped zone include: enhanced building standards for new construction in High and Very High zones (California Building Code Chapter 7A / Wildland-Urban Interface requirements such as ember-resistant vents, Class A roofs, and ignition-resistant exteriors) and mandatory defensible space (100 feet) under California Public Resources Code 4291. 13) covering mountain, valley-foothill, and desert areas designated as wildfire risk areas; the FS Overlay adds development standards including fuel modification, defensible space, and fire-resistant construction, and routes building/subdivision applications to the responsible fire authority for review. Property owners should check the County Fire FHSZ map viewer or the CAL FIRE FHSZ viewer to confirm their parcel's designation.