Wildfire Zones: Hesperia vs Ontario
How do wildfire zones rules compare between Hesperia, CA and Ontario, CA?
Ontario has fewer restrictions than Hesperia.
Hesperia, CA
San Bernardino County
Updated CAL FIRE/OSFM Fire Hazard Severity Zone maps significantly expanded Very High Fire Hazard Severity Zones (VHFHSZ) in Hesperia effective July 22, 2025. Properties in VHFHSZ must comply with Chapter 7A of the California Building Code (WUI ignition-resistant construction) and PRC §4291 defensible space.
View full Hesperia rules →Ontario, CA
San Bernardino County
Ontario sits on the valley floor and is not mapped in a CAL FIRE Very High Fire Hazard Severity Zone. Chapter 7A ignition-resistant construction and PRC 4291 defensible space do not apply citywide.
View full Ontario rules →Key Facts Comparison
| Fact | Hesperia | Ontario |
|---|---|---|
| Zone Designation | Expanded VHFHSZ effective July 22, 2025 | - |
| Authority | CAL FIRE/OSFM + SB County Fire (LRA) | - |
| Building Standard | CBC Chapter 7A (WUI construction) | - |
| Defensible Space | 100 ft per PRC §4291 | - |
| Zone 0 | 0–5 ft ember-resistant (AB 3074) | - |
| Disclosure | AB 38 buyer disclosure required in VHFHSZ | - |
| CAL FIRE status | - | Not in VHFHSZ |
| Chapter 7A | - | Not required citywide |
| PRC 4291 | - | Defensible space rule not triggered |
| Still required | - | Weed abatement and Fire Code |
| Map check | - | CAL FIRE FHSZ viewer |
Highlighted rows indicate differences between cities.
Hesperia FAQ
Is my Hesperia property in a wildfire zone?
Possibly. Updated VHFHSZ maps took effect July 22, 2025 and expanded coverage significantly. Check the CAL FIRE OSFM FHSZ viewer or City of Hesperia Building & Safety, and review Hesperia Information Bulletin IB-25-002.
What construction standards apply in VHFHSZ?
California Building Code Chapter 7A: ignition-resistant exterior walls, Class A roof, dual-pane tempered glass windows, ember-resistant vents (1/16–1/8 in mesh), protected eaves, and non-combustible decking near structures.
Do I have to disclose VHFHSZ when selling?
Yes. AB 38 (2019) requires sellers to disclose VHFHSZ designation to buyers and, for homes built before 2010, provide a home-hardening disclosure as part of the Natural Hazard Disclosure Statement.
What is Zone 0?
Zone 0 is the 0–5 ft ember-resistant zone immediately around a structure, mandated by AB 3074 (2020) and regulated by the California Board of Forestry. Combustible materials (wood mulch, fences attached to the home, stored items) must be removed.
Ontario FAQ
Is my Ontario home in a wildfire zone?
Almost certainly no. Ontario is on the valley floor with no designated Very High Fire Hazard Severity Zones, but always verify on the CAL FIRE viewer for your specific parcel.
Do I need Chapter 7A ignition-resistant siding in Ontario?
Not based on wildfire zoning, since Ontario has no VHFHSZ. Standard California Building Code materials are allowed.
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