Wildfire Zones: Ontario vs Rialto
How do wildfire zones rules compare between Ontario, CA and Rialto, CA?
Ontario has fewer restrictions than Rialto.
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 →Rialto, CA
San Bernardino County
Most of Rialto is in a Local Responsibility Area (LRA) Moderate / Non-VHFHSZ classification, but the northern foothill / Cajon Pass overlay touches CAL FIRE State Responsibility Area (SRA) Very High Fire Hazard Severity Zones (VHFHSZ). Properties within these zones face Cal. Public Resources Code §4291 100-ft. defensible space, Cal. Government Code §51182 vegetation requirements, and Cal. Building Code Chapter 7A WUI construction standards.
View full Rialto rules →Key Facts Comparison
| Fact | Ontario | Rialto |
|---|---|---|
| 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 | - |
| Most of city | - | LRA Moderate / unzoned |
| Northern foothill / Cajon Pass | - | SRA Very High Fire Hazard Severity Zone |
| Defensible space | - | 100 ft. (PRC §4291 / Gov. Code §51182) in VHFHSZ |
| New construction in WUI | - | Cal. Building Code Ch. 7A required |
| AB 38 sale disclosure | - | Required for VHFHSZ properties |
Highlighted rows indicate differences between cities.
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.
Rialto FAQ
How do I know if my Rialto property is in a wildfire zone?
Check the official CAL FIRE FHSZ Viewer (osfm.fire.ca.gov/fhsz). Most Rialto urban parcels are LRA Moderate; only northern/foothill parcels near Lytle Creek and the Cajon Pass are SRA VHFHSZ.
What do I have to do if I'm in a VHFHSZ?
Maintain 100 ft. defensible space per PRC §4291, comply with Ch. 7A construction standards for new builds/remodels, and disclose the zone at any sale per AB 38.
Does Rialto Fire inspect for defensible space?
Yes — Rialto Fire conducts annual weed-abatement inspections of all parcels under Mun. Code §15.28.060; CAL FIRE separately inspects SRA parcels for PRC §4291 compliance.
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