As California again delays controversial rules requiring homeowners in fire-prone areas to maintain a 5-foot “ember-resistant” zone around their houses, a new report finds that properties that were already close to that standard were much less likely to be destroyed in the devastating Los Angeles wildfires in January.
With ashes still smoldering, researchers with the Insurance Institute for Business & Home Safety, an industry-backed group, surveyed 252 homes that had been in the path of the blazes in Altadena and Pacific Palisades.
The group determined that of homes with more than half of their 5-foot zone covered in vegetation or other combustible material, 27% were completely destroyed. That share fell to 9% for homes with flammable material covering less than a quarter of the zone.
Roy Wright, chief executive of the institute, said the findings reveal that “there are ways that we can narrow the pathways of destruction” during climate-driven megafires and “we should have faith and trust in those strategies.”
But as the state works to craft the new fire safety rules ordered earlier this year by Gov. Gavin Newsom, homeowners have voiced concerns about the costs of removing plants, trees, wood fencing and other flammable materials, as well as the prospect of replacing landscaping with gravel or dirt. Some consumer advocates also contend the rules could be used by insurance companies, who’ve backed the regulation, to end homeowners’ coverage.
In response to disagreements over how strictly to enforce the “zone zero” requirements, the California Board of Forestry and Fire Protection said it would wait until March 2026 to continue working on the regulations, blowing past a Dec. 31 deadline to finalize the rules set by Newsom’s order. A 2020 law originally mandated a January 2023 deadline to complete the regulations.
According to Bloomberg News, the latest delay means it could be mid-2029 or later before any mandate takes effect for the roughly 2 million homes in high-risk fire areas, including parts of every Bay Area county except San Francisco.
“California is committed to getting Zone Zero right, not just getting it done, through rules that reflect what LA fire survivors have told us while balancing resilience to the next fire, the realities of the insurance market and what homeowners can reasonably afford,” Anthony Martinez, a spokesperson for Newsom, said in a statement.
The Eaton and Palisades fires in Los Angeles County killed 31 people and destroyed more than 16,000 structures, many of them homes, making the blazes among the most destructive wildfires in California history.
At the start of next year, Berkeley will enact similar 5-foot rules for around 1,000 homes in the Berkeley Hills. In 1991, a catastrophic firestorm killed 25 people and destroyed more than 3,000 homes in the Berkeley and Oakland hills.
While some homeowners supported the ordinance, others worried about costs and questioned whether the requirements were necessary.
“It’s a bit draconian to expect people to rip out existing vegetation that does not pose a fire hazard,” said resident Gina Rieger at the city council meeting in April. “You could have somebody with a succulent garden that they’ve tended for years and years and years.”
There’s a broad consensus among researchers, however, that maintaining “defensible space” around a home is an effective way to prevent embers from sparking a structure during a wildfire, said Michael Gollner, an associate professor of mechanical engineering at UC Berkeley who studies wildfire mitigation.
“This is one of the cheapest and easiest things that you can do that has any immediate and measurable impact,” Gollner said.
While acknowledging the inherent limitations of the latest insurance institute report — including that it assessed only burn areas where at least some homes survived — he described it as an “excellent additional source of information” to other recent studies.
One study by Gollener of more than 47,000 homes in five major California wildfires (excluding the recent Los Angeles fires) found that clearing vegetation within 5 feet, coupled with “home hardening” measures such as installing non-flammable siding and fine-mesh over vents, doubled a home’s expected survival rate from 20% to 40%.
In addition to home hardening, the insurance institute found that the spacing between homes was another critical factor, since a structure is more likely to catch fire if it’s close to another burning structure. Even for homes with fire-resistant features, the chance of evading damage was less than 50% when the nearest structure was within 10 feet. Each additional 10 feet of separation increased the likelihood of no damage by 7-13%, up to 30 feet.
Gollener noted since it’s not feasible to increase home spacing in existing neighborhoods, it’s crucial that all homeowners in fire-risk areas take steps to protect their properties from flames.
“You’re not just making a personal decision, you’re making it for your community,” he said. “We’ve learned that the whole community making a change is what really matters.”