Boulder County, CO Fire Regulations: Wildfire Zones (2026)
Key Facts
- Number of zones
- Three wildfire zones
- Full mitigation zones
- Zone 1 and Zone 2
- Code basis
- IWUI Code
- Key driver
- Post-Marshall Fire 2021
- Assessment
- Required before permit
Summary
Unincorporated Boulder County is divided into three Wildfire Zones. Building or expanding in Zone 1 (West County) or Zone 2 (East County) triggers wildfire mitigation code requirements, including ignition-resistant construction and defensible space. Zone 3 does not require full defensible space.
Full defensible space is required in Wildfire Zone 1 - West County and Wildfire Zone 2 - East County. Full defensible space is NOT required in Wildfire Zone 3 - East County.
Full Breakdown
Boulder County's wildfire mitigation code, strengthened after the December 2021 Marshall Fire, incorporates the International Wildland-Urban Interface (IWUI) Code. The standards "address ignition-resistant construction, defensible space, noncombustible perimeters, and other measures." They apply to new residences and commercial buildings, additions over 200 square feet, and larger accessory and agricultural structures in Zones 1 and 2. A wildfire mitigation assessment by a county specialist must be completed before a permit is issued; the specialist works with the homeowner to mark trees for removal to meet defensible-space standards. NWS designates three Fire Weather Zones by elevation across the county.
Violations & Fines
Enforced through the building-permit process; a permit is withheld until the wildfire mitigation assessment and required construction/clearing standards are met.
Frequently Asked Questions
What are Boulder County's wildfire zones?
Do wildfire rules apply if I remodel?
Sources & Official References
Other rules in Boulder County
Compare Boulder County to another location·View the Colorado fire regulations overview
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