Alameda County, CA Fire Regulations: Wildfire Zones (2026)
Key Facts
- Zone designation
- CAL FIRE VHFHSZ
- Defensible space
- PRC 4291, 100 feet
- Building standard
- CBC Chapter 7A
- Disclosure
- CA Civil Code 1103
- Historic fire
- 1991 Oakland Hills Firestorm
Summary
Much of east Alameda County including the Oakland Hills, Castro Valley, and Sunol foothills is designated Very High Fire Hazard Severity Zone by CAL FIRE, triggering strict defensible space rules.
The State Fire Marshal is mandated to classify lands within State Responsibility Areas into Fire Hazard Severity Zones (FHSZ). Fire Hazard Severity Zones fall into one of the following classifications: Moderate, High, Very High. The California laws that require Fire Hazard Severity Zones include California Public Resources Code 4201-4204, California Code of Regulations Title 14, Section 1280 and California Government Code 51175-89. The Fire Hazard Severity Zone (FHSZ) maps are developed using a science-based and field-tested model that assigns a hazard score based on the factors that influence fire likelihood and fire behavior.
Full Breakdown
CAL FIRE has mapped significant portions of unincorporated Alameda County as Very High Fire Hazard Severity Zones (VHFHSZ) in both State Responsibility Areas (SRA) and Local Responsibility Areas (LRA). The designation follows the devastating 1991 Oakland Hills Firestorm that killed 25 people and destroyed over 3,000 structures, and the 2017 Fountain Fire context. Properties in VHFHSZ are subject to PRC Section 4291 defensible space requirements, Chapter 7A ignition-resistant building standards for new construction and additions, and CA Civil Code 1103 natural hazard disclosure at point of sale. The Alameda County Fire Department and CAL FIRE Santa Clara Unit enforce defensible space inspections. Homeowners must maintain 100 feet of defensible space, use ember-resistant vents, Class A roofing, and address specific zone hardening under the Home Hardening program. Insurance availability and rates are significantly affected by VHFHSZ status.
Frequently Asked Questions
How do I find out if my property is in a VHFHSZ?
What are the insurance implications?
Sources & Official References
Other rules in Alameda County
California rules heatmap·Compare Alameda County to another location·View the California fire regulations overview
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