Colorado homeowners have been hearing about a new wildfire code for two years now, usually in the form of a rumor: that the state is going to make everybody replace their roof, or rip out their landscaping, or that nothing is required at all and the whole thing is voluntary.

The reality is narrower and more useful than either version. Colorado has a statewide model wildfire code. Local jurisdictions adopt it. Existing homes are generally allowed to stay as they are. And a short list of ordinary projects, the kind a homeowner does anyway, pulls a house into the requirements.

This is what the code actually contains, what triggers it, and what it means for a house that already exists.

Where the code came from

The Marshall Fire burned through Louisville and Superior on December 30, 2021. Boulder County identified 1,084 total losses. It was small by acreage and catastrophic by structure count, and it happened in neighborhoods that did not look like forest.

Colorado's legislative response was SB23-166, signed May 12, 2023, which created a Wildfire Resiliency Code Board and directed the Division of Fire Prevention and Control, within the Department of Public Safety, to develop statewide codes for wildfire resilience. The product is the Colorado Wildfire Resiliency Code, established July 1, 2025 as rule 8 CCR 1507-39. The rule describes the code as "an adaptation of Chapters 1, 2, 3, and 5 of the 2024 International Wildland Urban Interface Code by the International Code Council," plus other identified best practices. It is an adaptation of four chapters, not a wholesale adoption of the IWUIC.

The dates matter, and they were amended after the fact. SB23-166 originally gave local governing bodies three months from the board's adoption to adopt their own codes. SB25-142, signed June 3, 2025, changed that to nine months, which puts the local adoption deadline at April 1, 2026, with compliance required within three months of local adoption, so July 1, 2026 in practice.

The word "model" is doing real work here. The state set a minimum. Local governing bodies adopt a code that meets or exceeds it, so a jurisdiction can be stricter but not looser. Garfield County, for example, adopted the code effective July 1, 2026 and removed the state's 35-acre exemption.

Two exemptions from the statute worth knowing. A 35-acre parcel with a single residential structure that does not abut a residential or commercial area is exempt. And the statute is explicit that properties with a certificate of occupancy are not required to be in compliance before the sale or transfer of the property. There is no point-of-sale trigger.

Your fire marshal or building official is the authority on what applies at your address. Adoption status, hazard mapping, and local amendments all vary, and DFPC has not published a consolidated list of adopting jurisdictions. Nothing here is a substitute for asking them.

The part most homeowners get wrong: existing buildings

DFPC says it flatly: "This is not a retrofit code." Existing structures may generally continue as they are. The hardening requirements are permit-driven, attaching at new construction and at the moments an existing building is substantially altered.

Those moments are specific, and they are the practical center of the whole code for anyone who already owns a house. The statute sets the floor at three triggers: a permit increasing the footprint by 500 square feet including attachments, an exterior alteration or repair affecting 25 percent or more of the exterior, and adding a wooden deck. The code text is more granular:

• Roof. Replacing 25 percent or more of the surface area of the roof means the entirety of the roof covering has to be replaced to the new-construction standard (§101.6).
• Exterior walls. Where 25 percent or more of the total exterior wall surface area is replaced, the entire wall surface including attachments has to be brought to standard, and the immediate zone within 5 feet has to be brought into compliance too (§101.7).
• Additions. Work that increases the footprint of the existing structure by 500 square feet or greater conforms to new-construction requirements (§101.5).

Read that middle one again, because it is the one that surprises people. A significant siding job does not just change the siding. It reaches into the landscaping in the first five feet.

And the statute is equally clear about what is not covered: the codes do not apply to interior alterations. Remodeling a kitchen does not pull your lot into a defensible space requirement.

Fire intensity classification: what class is your property

This is the part most summaries get wrong, and it changes what a given homeowner owes.

The code sorts property into three fire intensity classifications, keyed to modeled flame length and derived from the 2022 Colorado Wildfire Risk Assessment fire intensity scale (§303.2):

• Low. Flame length less than 2 feet. Light to medium surface fuels, grasses and scattered vegetation, gentle to moderate slope. Generally suppressible with hand crews.
• Moderate. Flame length up to 8 feet. Denser shrubs, small trees, accumulated litter. Slopes over 30 percent accelerate fire behavior. Short-range spotting is common.
• High. Flame length up to 30 feet or more. Heavy continuous fuels, dense canopy, heavy dead and downed material, slopes often over 40 percent. Direct attack is generally ineffective.

Those three intensity classifications map onto two construction classes. Low intensity is Class 1. Moderate and High are both Class 2.

The practical consequence: a Class 1 property owes the immediate zone only. The intermediate and expanded zones attach in Class 2 areas. Knowing which class your parcel is mapped as is the single most useful thing you can learn about how this code touches you.

The classification is recorded on official maps built from fuels, topography, local weather, and fire behavior modeling, and the local authority may develop its own maps (§303.1).

If you think your mapped class is wrong, the code has a process for that. Under §304, an owner may request a site-specific review of the mapped classification. The determination considers fuels within 300 feet of the parcel boundary, and the request has to be supported by technical documentation from a qualified wildfire professional. That is an unusual and worthwhile provision: the map is not the last word, but contesting it takes evidence, not opinion.

The three ignition zones

The code organizes defensible space into Structure Ignition Zones measured outward from the house, and it points directly at the Colorado State Forest Service Home Ignition Zone guide as its reference (§501.2). If you have read anything about home ignition zones from CSFS or NFPA Firewise USA, these distances will look familiar, because they are the same framework. Our zone-by-zone defensible space guide walks the same three rings in a Texas context.

Note the code's own vocabulary: the third ring is the Expanded zone, not the Extended zone that most national material uses. Same distances, different word.

Zone 1, Immediate, 0 to 5 feet. This is the Class 1 requirement, meaning it applies everywhere the code applies. Noncombustible or hard surfaces only: rock, gravel, concrete, pavers, bare earth. Remove all plantings other than those the local authority accepts as ignition resistant. No new trees. Mature trees 10 inches in diameter or larger may remain. Prune tree crowns to 10 feet of clearance from the structure.

Zone 2, Intermediate, 5 to 30 feet. Class 2 areas only. Remove dead material from live vegetation. Avoid accumulating surface fuels: logs, slash, deep mulch. Space trees and shrubs so fuel is discontinuous, with shrubs kept at least 10 feet from the edge of tree branches.

Zone 3, Expanded, 30 to 100 feet. Class 2 areas only. The goal shifts from removal to keeping fire on the ground. Minimum tree crown spacing of 6 to 10 feet.

There is also a site signage requirement that gets ignored and should not be. Road and driveway marking, hydrant and fire equipment marking, and permanent address markers visible from both directions, posted at the driveway entrance. If a fire crew cannot find your driveway at 3 a.m. in smoke, everything else you did in the first hundred feet matters less.

What "hardening" actually means

Chapter 4 is the structure hardening chapter. These are prescriptive and testable, which is what makes them useful to document. The main ones:

• Roofing (§403.2). Class A roof covering or assembly, tested to ASTM E108 or UL 790. Gaps in profiled roofing firestopped. Valley flashings at least 0.019 inch (No. 26 gauge) corrosion-resistant metal over a 36 inch cap sheet underlayment.
• Gutters and downspouts (§403.3). Noncombustible.
• Vents (§403.4). Attic, rafter, and underfloor vents either tested to ASTM E2886 for ember and flame intrusion, or covered with noncombustible one-eighth inch mesh. This is one of the cheapest items on the list and one of the most consequential, because vents are how embers get inside a house that never caught fire on the outside.
• Eaves and soffits (§403.5). Protected underside: noncombustible material, five-eighths inch Type X drywall, fire-retardant-treated wood, or equivalent. Fascia protected.
• Exterior walls (§403.6). One-hour rated, or noncombustible, or heavy timber or log, or fire-retardant-treated wood, or ignition resistant, from foundation to roof. Six inches of vertical noncombustible flashing where walls meet ground, decks, or roofs. Vinyl siding only over a compliant substrate.
• Decking (§403.8). Walking surface noncombustible or Class A, with a Class B composite exception.
• Glazing (§403.10). Tempered glass, multilayered glazed panels, glass block, or a 20 minute or better fire rating.
• Exterior doors (§403.11). Noncombustible, or solid core at least one and three-quarter inches, or 20 minute rated.
• Garage doors (§403.12). Perimeter ember gaps no larger than one-eighth inch, achieved with tested weather-stripping or metal-flashed jambs.

The pattern across all of it is embers, not flame front. Most of these requirements exist because a house half a mile from the fire can ignite from a shower of embers landing in a vent, a gutter, a deck gap, or a mulch bed.

What to do with this if you own an existing Colorado home

Three things are worth doing regardless of whether the code has been adopted where you live.

Find out your jurisdiction's status. Adoption is local. Call the fire protection district or the building department and ask two questions: have you adopted the Wildfire Resiliency Code, and what fire intensity class is my parcel mapped as. Both answers are free.

Sequence the work around the triggers you already have coming. If a roof replacement is two or three years out, that is the moment the roofing standard attaches, and knowing it now changes how you budget. Same with siding, and siding brings the first five feet with it.

Build the record before you need it. Two of the code's own mechanisms run on documentation. The §304 site-specific review requires technical documentation from a qualified wildfire professional to contest a mapped class. Colorado's wildfire mitigation tax credit (C.R.S. § 39-22-543) is receipt-driven: it covers 100 percent of qualifying costs up to a $1,000 credit for tax years 2025 through 2027, subject to a federal taxable income limit, and only for costs paid to a third-party service provider, not for your own labor or for materials you buy. Qualifying work is defensible space, fuel breaks, thinning woody vegetation, and secondary treatment of woody fuels, meeting state forest service standards. Home hardening does not qualify. It is non-refundable with no carryforward, so confirm the current year's figures with the Colorado Department of Revenue or your tax professional.

Beyond either of those, a homeowner who can show what the property looked like before and after a season of fuel reduction is in a materially different position than one working from memory.

That last part is the piece we work on. Home Health Intel produces a dated, structured photo record of a home's condition across the zones and the hardening items above, which the homeowner owns and keeps. It is not a code inspection, it does not certify compliance, and it does not substitute for your fire marshal. It is a record of condition, on file, in your name.

If you want a starting point that costs nothing, our address check reads the public hazard record for a location and tells you which perils are worth assessing where you live.

Check your address

Home Health Intel documents condition. We are not a public adjuster (C.R.S. § 10-2-417). Carrier underwriting decisions are theirs alone.

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Statutory provisions above are from SB23-166 and SB25-142 (C.R.S. §§ 24-33.5-1236 and 24-33.5-1237) and the Colorado Wildfire Resiliency Code adopted as 8 CCR 1507-39 by the Division of Fire Prevention and Control. Section numbers follow the code text; individual jurisdictions adopt their own versions, which may be stricter, and section numbering can vary between adoptions. Tax credit terms from the Colorado Department of Revenue. Zone framework corroborated by the Colorado State Forest Service Home Ignition Zone guide. Confirm what applies to your address with your local fire marshal or building official. This article is general education, not legal, financial, tax, or insurance advice.