You Did Zone 0 Right. Here's Why That's Only Half the Job.
I get a version of the same question a lot from homeowners who've just finished clearing their five feet: "Okay, I did Zone 0. Am I done?" I understand why it feels that way — it's real work, it's the thing CAL FIRE and your local fire department keep telling you to do, and checking it off feels like closing the loop. After the 2018 Woolsey Fire burned through the hills near my home in West Hills, I went through CERT training and started building wildfire defense equipment for homeowners, and the thing I keep coming back to is this: Zone 0 is the right first move, and it isn't the whole plan. Here's the gap between “compliant” and “actually defended,” and what belongs in that gap.
What Zone 0 Is Actually Designed to Do
Zone 0 — the five feet of ground touching your home — exists to deny an ember a place to catch. No mulch, no firewood, no dead branches, no combustible fencing butted against the wall. If that zone is clean, an ember that drifts onto it has nothing to ignite. That's a genuinely effective piece of engineering, and it's why defensible space requirements (Zone 0, plus the broader Zone 1 and Zone 2 vegetation-management rings further out) are the backbone of California's wildfire policy. None of what follows is an argument against doing it. Do it. It's necessary.
It's just not sufficient on its own, and the reason is simple: Zone 0 only controls what's sitting on the ground next to your house. It doesn't control the roof, the vents, the gutters, the open window, or the fact that your neighbor two doors down may not have cleared their five feet at all.
Where Embers Still Get Through a Clean Zone 0
- Roofs and gutters. Dry leaves and debris in a gutter, or a roof material that isn't Class A fire-rated, give an ember a landing spot that has nothing to do with the ground around your foundation.
- Vents. Attic, crawlspace, and foundation vents are built-in openings. Without fine, corrosion-resistant mesh screening, they're a direct path for embers to get inside the structure — past every bit of work you did outside.
- Windows left open, or single-pane glass. Radiant heat can crack single-pane glass well before direct flame contact, and an open window during a wind event is an invitation regardless of what's happening five feet away.
- Decks, eaves, and anything overhanging. Embers don't just fall straight down — wind carries them sideways and up, into spots Zone 0's ground-level clearing was never designed to reach.
- Your neighbors' properties. Zone 0 is a property-by-property rule. A fully compliant yard next to a non-compliant one still sits inside the same wind-driven ember field during a fire.
- A fire that simply reaches the structure. Defensible space reduces the odds of ignition; it isn't fire suppression. If flame or ember contact happens anyway — through a gap, a vent, or a missed spot — nothing about Zone 0 puts water on it.
The Second Layer: What's Actually in the Gap
This is the layer most homeowners I talk to haven't touched yet, because it's less visible than yard work and it requires owning equipment instead of just removing things. It comes in two parts.
Home hardening closes the structural gaps: ember-resistant vents with fine mesh screening, a Class A roof kept clear of debris, boxed-in eaves, dual-pane (ideally tempered) windows, and decks enclosed or cleared underneath. This is the layer that decides whether an ember that gets past your landscaping can actually get into your house.
Active equipment is what you reach for if an ember lands, a spot fire starts, or flame reaches the property despite everything above. That means a hose matched to your hydrant's thread standard, a wrench to operate the hydrant's main valve, a nozzle to control the spray pattern, and — if you want to cover two sides of the house at once — a gated wye valve to split one hydrant connection into two independently controlled lines. None of that equipment does any good if it's still in boxes the first time you need it. It has to be connected, tested, and familiar before a Red Flag Warning, not during one.
What You Need to Know
- Zone 0 and equipment aren't competing priorities — they're sequential layers. One reduces the odds a fire starts at your house. The other is what you use if it does anyway.
- Home hardening is often the most overlooked piece. Vents, roofing material, and window glazing don't show up on a defensible-space inspection the way a messy yard does, but they matter just as much.
- Check your local rules before relying on a hydrant. Civilian hydrant access is restricted or requires advance notification in many jurisdictions — confirm with your fire department or water utility ahead of time, not in the moment.
- Practice the whole system on a calm day. Connect your hose, valve, wrench, and nozzle together at least once before fire season, so you're not learning the parts while embers are falling.
- None of this replaces an evacuation order. If authorities tell you to go, go. This layer is for the window before that order comes, not a reason to stay past it.
Clearing your five feet is the first layer, and it's a good one. The second layer is the equipment that's actually sitting ready to go the day the first layer wasn't quite enough — a gap in the fence, an open vent, an ember that found the one spot you missed. If your garage still has that equipment in its original packaging, that's the gap to close next.
Sherwin Ross is the founder of Ace Fire Defense, based in West Hills, CA. After the 2018 Woolsey Fire, he became CERT-trained and started building wildfire defense equipment for homeowners.