The Boulder City Council last week gave initial approval to new home hardening rules aimed at reducing wildfire risk in the city’s most vulnerable areas by prohibiting flammable materials on and around new homes.
The proposal is part of Boulder’s broader effort to adapt to a year-round fire season and the growing wildfire threat fueled by climate change. Residents have already seen insurance premiums rise — or lost coverage altogether — due to the city’s wildfire risk. The 2021 Marshall Fire, which destroyed more than 1,000 homes, spread rapidly through neighborhoods as hot embers jumped across wooden fences and dry vegetation. Since then, city fire officials have warned that a wildland fire within city limits is not a matter of if, but when.
In response, city staff have been updating building and land use codes to help slow the spread of fire in residential areas. In March 2025, the council approved building code changes requiring permits for new siding and window replacement projects. Additional landscaping regulations are expected later this year.
The newly proposed rules would apply only to new construction and additions or remodels in the city’s wildland-urban interface (WUI) – the zone where homes border flammable landscapes, primarily along Boulder’s western edge.
Under the proposed ordinance, new homes in the WUI would need a five-foot buffer of noncombustible material around the structure. Any fence or gate within eight feet of the home must be built from non-combustible material. The surface of decks must be built with fire-resistant lumber. Plants around the home must meet “low-flammability” ratings. Juniper trees, which are highly combustible, would be prohibited.
The ordinance would also expand the boundaries of the city’s WUI zone, increasing the number of properties subject to these regulations from about 4,700 to roughly 16,400. This includes parts of eastern Boulder previously left out.
Councilmembers in December had asked staff to explore requiring compliance with the new rules when selling a home or obtaining a rental license. The goal was to have the regulations include more existing homes to help ensure that properties lacking fire mitigation don’t endanger neighboring homes that have taken steps to reduce their risk.
But such provisions were not included in the current proposal and remain under review, according to city officials. City Attorney Teresa Tate has said that applying the rules retroactively to existing properties could be legally problematic. Additionally, city officials have said that implementing such broad measures would require additional city resources for education and enforcement.
Before last week’s city council meeting, Councilmember Matt Benjamin suggested requiring that homeowners with high-risk properties get a detailed home assessment by wildfire experts. The recommendation will not be included in the current code update.
“This would ensure that we as a city know that property owners know that not only is their property a risk to themselves, but a risk to others, and that the [Boulder Fire-Rescue] has provided them with details on how to make their property safe and fire-wise,” Benjamin wrote in an email to city officials.
The council is scheduled to hold a public hearing and final vote on the WUI code change on May 15. If approved, the new rules would take effect in August.
The post No plants, no wood fences: Boulder proposes ban on flammable materials within 5 feet of new homes in wildfire zones appeared first on The Boulder Reporting Lab.