AB 3074 and Ember-Resistant Vents: What California Homeowners Need to Know

California Assembly Bill 3074, signed into law in 2020, created a new ember-resistant zone, known as Zone Zero, covering the first five feet around a home in a Very High Fire Hazard Severity Zone. Ember-resistant vents are often mentioned in the same breath, but they are a separate subject. Vents are not a requirement of AB 3074. They are, however, one of the most important upgrades a property owner can make.

What AB 3074 Requires

The law reflects what wildfire research keeps showing: the area right next to a structure is where embers are most likely to find fuel and start a fire that spreads to the home.

Meeting the Zone Zero standard means keeping that five-foot area free of combustible materials that could carry fire to the structure. Typical examples are bark mulch, dead vegetation, wood furniture and storage, and flammable fencing or attachments touching the home. The specific requirements and compliance timelines come from regulations set by the State Board of Forestry and Fire Protection and enforced by your local fire authority. Check the current requirements for your jurisdiction before treating them as enforceable on your property. Our [Requirements Finder](/requirements) shows where they stand for your address.

Zone Zero compliance is the starting point, not the finish line. The strongest protection comes from treating the home and the land around it as one system: Zone Zero, defensible space beyond it, and a hardened structure.

Recommended Upgrade: Ember-Resistant Vents

Not required under AB 3074, but strongly recommended.

For property owners in High and Very High Fire Hazard Severity Zones (HFHSZ and VHFHSZ), upgrading vulnerable vents should be a top priority in a complete home-hardening plan. Protecting these openings closes a critical pathway through which wildfire can enter a home.

Small Embers. Serious Consequences.

California's Office of the State Fire Marshal reports that 60 to 90 percent of home ignitions during wildfires are caused by embers. Wind can carry these burning particles miles ahead of the fire front, so homes are exposed before the flames arrive. (osfm.fire.ca.gov, ibhs.org)

Embers can get in through attic, gable, roof, eave, soffit, and crawl-space vents. Once inside, they can ignite debris and other combustible materials in concealed spaces. A fire that starts in an attic or under a home can grow out of sight, which is why these areas matter so much. IBHS research identifies vents as a significant weak point for wind-driven ember intrusion. (ibhs.org, fire.ca.gov)

That ember ignition figure covers several pathways, not vent intrusion alone. It still shows why protecting openings deserves prompt attention.

Upgrade a Critical Point of Vulnerability

Purpose-built flame- and ember-resistant vents help keep embers out of concealed spaces while still allowing the airflow the building needs. CAL FIRE recommends vents approved by the California State Fire Marshal, installed properly and with attention to ventilation requirements. (fire.ca.gov)

Vent upgrades work best as part of a broader plan that also covers Zone Zero, defensible space, roofing, gutters, eaves, windows, and other vulnerable components. Together, these improvements reduce the chances that wildfire ignites the structure. (ibhs.org, fire.ca.gov)

Qualified to Assess. Capable of Retrofitting.

California Fire Safe Solutions (CaliFSS) combines wildfire mitigation expertise with licensed general contracting, so we can take your property from assessment through installation. Our leadership brings extensive wildland and municipal firefighting experience, plus more than 40 years of construction experience in retrofits, remodels, and new construction.

We evaluate your existing vents, identify the vulnerable openings, recommend appropriate listed products, and perform retrofits suited to how your home is built. We account for vent placement, fit, surrounding gaps, required airflow, and the manufacturer's installation instructions. These details decide how well the finished work protects your home.

Make ember-resistant vents a priority before the next wildfire reaches your community. Contact CaliFSS to schedule a property assessment and talk through practical retrofit options.