Zone Zero · City & County of San Diego

The Fires That Wrote the Law: San Diego

Zone Zero exists because of what fire has repeatedly done inside San Diego County, not in distant forests. From the 2003 Cedar Fire, once the largest wildfire in California history, to the 2007 Witch Creek and Harris Fires, San Diego's worst home losses came from wind-blown embers igniting the first five feet, the ember-resistant zone, around houses.
Get Your Free Assessment See the Deadlines
The Record

Three firestorms, one pattern

Four years, three separate ignitions, the same mechanism. Santa Ana winds carried embers ahead of the fire front, into mulch, fences, and vegetation against homes, and turned wildland fires into neighborhood fires.

Structures destroyed countywide, San Diego firestorms · 2003 & 2007
Cedar Fire, Oct 2003: 2,820 buildings destroyed countywide, 335 within San Diego city limits (Scripps Ranch, Tierrasanta) Cedar · 2003 2,820 Witch Creek and Guejito Fires, Oct 2007: 1,141 residences destroyed countywide, 365 within San Diego city limits (all in Rancho Bernardo) Witch Creek · 2007 1,141 Harris Fire, Oct-Nov 2007: 253 residential structures and 293 outbuildings destroyed, Potrero to Jamul, extending into Mexico Harris · 2007 253
Countywide structure counts per City of San Diego official fire history and Harris Fire (Wikipedia, sourced to CAL FIRE incident data). Cedar 2003 and Witch Creek/Guejito 2007 figures also include structures destroyed within San Diego city limits. Both 2007 fires struck communities, Rancho Bernardo and Ramona, that hadn't seen a major fire in living memory.
October 2003

Cedar Fire

Started by a signal fire from a lost hunter in the Cleveland National Forest, the Cedar Fire grew from 20 acres to 62,000 acres in under 12 hours and reached the city limits of San Diego by the next morning. It burned 280,278 acres countywide, destroyed 2,820 buildings, and killed 15 people, the largest wildland fire in California history at the time. Scripps Ranch and Tierrasanta, both well inside the city, took the heaviest damage: 335 structures lost and $204 million in losses within city limits alone.

October 2007

Witch Creek & Guejito Fires

Two fires that started a day apart east of Ramona and in the San Pasqual Valley merged into one front and triggered the largest evacuation in county history: more than 500,000 residents, including 200,000 inside San Diego city limits. Rancho Bernardo, a neighborhood with no significant fire history, lost 365 homes in a single event. Countywide, the fires destroyed 1,141 residences and burned nearly 198,000 acres.

October–November 2007

Harris Fire

Igniting near Potrero on the same Santa Ana wind event, the Harris Fire pushed northwest through backcountry communities toward Jamul and Chula Vista and burned into northern Mexico near Tecate. It destroyed 253 homes and 293 outbuildings and killed 8 people across 90,440 acres, the deadliest of the 2007 firestorms.

The Science

Why Zone 0 targets five feet, not five hundred

Most homes lost in wildfires are not touched by the fire front. They ignite from embers: burning fragments carried by Santa Ana winds, sometimes more than a mile ahead of the flames, the exact pattern that jumped the Cedar Fire into Scripps Ranch and the Witch Creek Fire into Rancho Bernardo.

The Insurance Institute for Business & Home Safety (IBHS) demonstrated this in full-scale ember-storm testing: what determines survival is the material in the first five feet. Mulch beds, fences, doormats, and plants against walls. That research is the scientific spine of AB 3074, the 2020 law that created Zone Zero.

SB 504 (2024) gave the Board of Forestry enforcement authority, and AB 1455 (2025) set the compliance timeline. San Diego's own fire record, and San Diego Fire-Rescue's decision to set a local target date, is why the city is expected to enforce it seriously.

See every Zone Zero deadline →
EMBERS TRAVEL 1 MILE + 0–5 FT
The fire front never has to arrive. The first five feet decide what an ember can do.
2/3

Roughly two-thirds of the City of San Diego, more than 220,000 properties, sits inside a Very High Fire Hazard Severity Zone under the city's 2025 Fire Hazard Zone map. That is the scale San Diego Fire-Rescue is enforcing against with its own February 2027 target date.

Common Questions

Fire history questions, answered

Was the Cedar Fire really the largest wildfire in California history?

At the time, yes. The October 2003 Cedar Fire burned 280,278 acres countywide, the largest wildland fire recorded in California history at that point, and remains the deadliest and most destructive fire San Diego County has seen.

My neighborhood has never burned. Does Zone Zero still apply?

If you're in a Very High Fire Hazard Severity Zone, yes. Ember cast doesn't respect fire history. Scripps Ranch and Tierrasanta had no major fire history before 2003; Rancho Bernardo had none before 2007.

Where can I check my home's hazard zone?

The City of San Diego's 2025 Fire Hazard Zone map places roughly two-thirds of the city, over 220,000 properties, inside a Very High Fire Hazard Severity Zone. A free assessment will confirm your parcel's status.

Don't be the case study

Find out what your first five feet look like to an ember, before the next Santa Ana event. The assessment is 100% free.

Get Your Free Assessment Questions? Talk to an Agent