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Colorado Counties
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Overview
Colorado has NO statewide building code for residential construction. Local jurisdictions (cities, counties) independently adopt and enforce IRC/IBC editions - varies widely from IRC 2015 to IRC 2024. STATE REQUIREMENTS: (1) Energy code minimum IECC 2021 required when jurisdictions update codes (per SB23-016); (2) Model LECC (based on IECC 2024) becomes minimum July 2026; (3) Electrical: NEC 2023 statewide via DORA State Electrical Board; (4) Plumbing: UPC via State Plumbing Board. Division of Housing enforces codes for manufactured homes and factory-built buildings. Division of Fire Prevention enforces codes for K-12 schools and healthcare facilities. 64 counties. Climate zones 4B/5B/6B/7 vary by elevation. Mountain regions (5B/6B/7) have stringent energy requirements. Denver, Colorado Springs, Fort Collins, Aurora use IRC 2021 or 2024 with local amendments. CRITICAL: Always verify current code adoption with local jurisdiction before starting work - no statewide uniformity.
Code Snapshot
Current editions in effect
Energy
CO-EC 2021
2021 Edition
Fire Code
CO-FC 2021
2021 Edition
Code
DOH Current
Current
Plumbing
IAPMO 2021
2021 Edition
Building Code
IBC Local Adoption
Local Adoption
Code
ICC Local Adoption
Local Adoption
Effective Date: January 1, 2024
Verified: Mar 2026
Jurisdiction Complexity
Colorado is a MODERATE complexity state
Colorado applies state-level code amendments to ICC base codes, with some variation across local jurisdictions.
SimpleModerateComplex
Wind-Borne Debris
Varies by locality →Key Rules & Requirements
Critical regulations for Colorado restoration work
Colorado has no mandatory statewide residential code. Each municipality and county adopts independently. Denver, Colorado Springs, and Front Range cities typically adopt recent IRC. Mountain communities may have additional snow/wildfire requirements.
Important: Colorado does not have a mandatory statewide residential building code. Cities and counties adopt codes independently, resulting in significant variation. The Division of Housing (DOH) administers factory-built structures. Major Front Range cities (Denver, Colorado Springs, Aurora, Fort Collins, Boulder) generally adopt recent IRC editions with local amendments. Mountain communities often have additional requirements for snow loads, wildfire mitigation, and access. Denver has its own amendments (Denver Building Code). Rural unincorporated areas may have no adopted code. The Colorado Association of Building Officials (CABO) promotes code uniformity but adoption remains voluntary.
Colorado has extreme variation in ground snow loads, from 20 psf on the eastern plains to 200+ psf in mountain areas. Roofs must be designed for the local ground snow load per ASCE 7.
Important: Colorado ground snow loads vary dramatically by elevation and geography. Eastern plains: 20-30 psf. Front Range cities: 25-35 psf. Mountain communities: 60-200+ psf. ASCE 7 ground snow load maps provide baseline values, but many mountain jurisdictions have adopted local snow load maps with site-specific values. Roof design must account for the applicable ground snow load converted to roof snow load per ASCE 7 methodology (considering roof slope, exposure, thermal factor, and importance factor). Drift loads at parapets, roof-level changes, and adjacent structures must also be considered. Reroofing projects should verify the structure can support the new roof system weight plus snow loads.
Colorado communities in Wildfire-Urban Interface zones require fire-resistant roofing, siding, and defensible space. Many mountain and foothill communities have adopted IWUI code or local equivalents.
Important: Colorado has significant WUI exposure, particularly along the Front Range foothills and mountain communities. After devastating fires (Black Forest 2013, Marshall Fire 2021), many jurisdictions adopted enhanced wildfire mitigation requirements. Common requirements include: Class A fire-rated roofing materials, non-combustible or ignition-resistant siding within WUI zones, defensible space (typically 100+ feet), enclosed eaves and soffits, and ember-resistant vents. Some jurisdictions have adopted the International Wildland-Urban Interface Code (IWUIC). Boulder County, Jefferson County, El Paso County, and Larimer County all have WUI-specific building requirements.
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Code Administration
Administering Agency
Colorado Building Commission
Code Portal
energyoffice.colorado.govState Statute
View StatuteQuick Statistics
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Jurisdictions
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ZIP Codes
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Special Zones
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Codes
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Climate Zones
Applicable Codes
Key Codes for Restoration Work
Primary codes for residential restoration projects in Colorado
| Code Type | Current Edition | Effective Date | Base Code | Status | Actions |
|---|---|---|---|---|---|
Colorado Energy Code (Minimum) Energy Efficiency Standards | CO-EC 2021 | Jan 1, 2024 | IECC 2021 w/ amendments | Current | View Details |
International Building Code Commercial & Multi-Family | IBC Local Adoption | Jan 1, 2024 | IBC 2021 w/ amendments | Current | View Details |
International Existing Building Code Commercial & Multi-Family | IEBC Local Adoption | Jan 1, 2024 | IBC 2021 w/ amendments | Current | View Details |
International Energy Conservation Code (Commercial) Energy Efficiency Standards | IECC-C Local Adoption | Jan 1, 2024 | IECC 2021 w/ amendments | Current | View Details |
International Energy Conservation Code (Residential) Single-Family & Townhomes | IECC-R Local Adoption | Jan 1, 2024 | IRC 2021 w/ amendments | Current | View Details |
National Electrical Code 2023 (NFPA 70) Building Requirements | NEC 2023 | Jan 1, 2024 | NEC 2021 w/ amendments | Current | View Details |
Colorado Energy Code (Minimum)
Energy Efficiency Standards
CO-EC 2021Details
International Building Code
Commercial & Multi-Family
IBC Local AdoptionDetails
International Existing Building Code
Commercial & Multi-Family
IEBC Local AdoptionDetails
International Energy Conservation Code (Commercial)
Energy Efficiency Standards
IECC-C Local AdoptionDetails
International Energy Conservation Code (Residential)
Single-Family & Townhomes
IECC-R Local AdoptionDetails
National Electrical Code 2023 (NFPA 70)
Building Requirements
NEC 2023Details
Effective dates reflect when each code edition was formally adopted by the state. Dates may differ across code types when amendments are adopted in separate rulemaking cycles. Base codes reference the ICC model code edition that serves as the foundation for the state's adopted version. Verify current applicability with your local Authority Having Jurisdiction (AHJ).
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Enter a Colorado ZIP code for exact applicable codes, special zones, and a compliance checklist.
Special Zones
Special Zones
Wind & Hurricane
Colorado Eastern Plains Tornado Zone
Eastern Colorado plains from Weld County through Kit Carson and Cheyenne counties are in the western extension of Tornado Alley. Weld County consistently ranks among the top tornado-producing counties nationally. The 2008 Windsor tornado (EF3) caused significant damage. Enhanced wind design per ASCE 7-22 and safe room provisions per FEMA P-361 are recommended for residential construction on the Eastern Plains.
Radon
Colorado EPA Radon Zone 1 — Front Range and Mountains
The majority of Colorado falls within EPA Radon Zone 1 with predicted indoor screening levels above 4 pCi/L. The Front Range urban corridor from Fort Collins to Pueblo has particularly high radon levels due to granitic bedrock and uranium-bearing Pierre Shale. IRC R324 radon-resistant new construction is required by many Colorado jurisdictions. Colorado Department of Public Health tracks radon by county.
Flood & Coastal
Colorado Flood Hazard Zones
Front Range urban areas, mountain valleys, Arkansas River corridor, South Platte River basin. 2013 Front Range floods caused $4 billion in damage. Flash flood risk significant in mountain canyons.
Requirements: Base Flood Elevation compliance required; Local floodplain administrator approval required; Elevation certificates required; FEMA flood insurance required in Special Flood Hazard Areas; Floodproofing for non-residential
View sourceWildfire
Colorado Wildland-Urban Interface Zone
WUI fire risk is significant statewide. Mountain communities, foothills, and interface areas throughout Colorado require fire-resistant construction. 2021 Marshall Fire destroyed 1,000+ structures in Boulder County.
Requirements: Ember-resistant vents required; Non-combustible siding recommended; Tempered glass windows recommended; Class A fire-resistant roofing required in many jurisdictions; IRC R327/IBC Chapter 7A where adopted; 100ft defensible space typical
View sourceGeologic
Colorado Front Range Expansive Soil Zone
Colorado's Front Range from Fort Collins through Denver to Colorado Springs contains some of the most problematic expansive soils in North America. Pierre Shale and bentonite clay can exert swell pressures exceeding 15,000 psf. Colorado Geological Survey identifies expansive soil hazards by county. Foundation design per IBC 1808.6 requires deep piers (typically 20-25 feet into bedrock), structural slabs, and moisture management systems.
Snow & Ice
Colorado Extreme Snow Load Zone
Mountain communities with extreme snow loads: Summit County (Breckenridge, Frisco), Eagle County (Vail), San Juan County (Silverton), Clear Creek County, Grand County. Wolf Creek Pass area can exceed 200 psf ground snow.
Requirements: Site-specific snow load study may be required; Per ASCE 7 with drift considerations; Required on metal roofs; Protection required for entries; 80-200+ psf depending on location
View sourceSeismic
Colorado Seismic Zone — Front Range Faults
Colorado has several active fault systems including the Ute Pass Fault, Rampart Range Fault, and faults near Trinidad. The 2011 Trinidad earthquake (magnitude 5.3) was linked to wastewater injection. Denver metro area is Seismic Design Category B per ASCE 7-22. The Sawatch Range and San Luis Valley have moderate seismicity. All structures must meet minimum seismic detailing per IBC Chapter 16.
Climate & Energy
Climate Zones
IECC Climate Zones in Colorado
4BMixed-Humid
Zone 4B - Mixed Dry
dry
5BCool-Humid
Zone 5B - Cool Dry
dry
6BCold
Zone 6B - Cold Dry
dry
7Very Cold
Zone 7 - Very Cold
Energy Code Requirements
IECC 2021 - Residential Insulation Minimums
| Component | Zone 4B | Zone 5B | Zone 6B | Zone 7 |
|---|---|---|---|---|
Ceiling Attic | 49.0 | 49.0 | 49.0 | 49.0 |
Wood Frame Wall | 20.0 | 20.0 | 20.0 | 20.0 |
Mass Wall | 13.0 | 17.0 | 20.0 | 21.0 |
Floor | 19.0 | 30.0 | 30.0 | 38.0 |
Basement Wall | 10.0 | 15.0 | 15.0 | 15.0 |
Slab Perimeter | 10.0 | 10.0 | 10.0 | 10.0 |
Crawl Space Wall | 10.0 | 15.0 | 15.0 | 15.0 |
Window | 0.320 | 0.300 | 0.300 | 0.300 |
Skylight | 0.550 | 0.550 | 0.550 | 0.550 |
Door | 0.350 | 0.350 | 0.350 | 0.350 |
Legend:
Ceiling Attic
Wood Frame Wall
Mass Wall
Floor
Basement Wall
Slab Perimeter
Crawl Space Wall
Window
Skylight
Door
NR = Not Required
Fenestration Requirements
U-Factor (Max)
0.320
SHGC (Max)
0.40
Ice Barrier
Required
R-Value Requirements (Zone 4B - Most Common)
R-49.0
Ceiling
Attic/Roof
R-20.0
Walls
Wood Frame
R-19.0
Floor
Over Uncond.
R-10.0
Basement
Wall
R-10.0
Slab
Perimeter
NR
Crawlspace
Not Required
Counties
Colorado Counties
64 jurisdictions with code information
Adams County
FIPS: 08001
Standard
26 ZIP codesView
Alamosa County
FIPS: 08003
Standard
4 ZIP codesView
Arapahoe County
FIPS: 08005
Standard
29 ZIP codesView
Archuleta County
FIPS: 08007
Standard
5 ZIP codesView
Baca County
FIPS: 08009
Standard
6 ZIP codesView
Bent County
FIPS: 08011
Standard
5 ZIP codesView
Boulder County
FIPS: 08013
Standard
31 ZIP codesView
Broomfield County
FIPS: 08014
Standard
3 ZIP codesView
Chaffee County
FIPS: 08015
Standard
6 ZIP codesView
Showing 9 of 64 jurisdictions.
Inspection Process
Inspection Process
Standard permit inspection sequence for Colorado residential projects
1
Footing Inspection
Before concrete pour for footings
2
Foundation Inspection
Before backfill of foundation walls or concrete pour for slab
If applicable
3
Underground/Underslab Plumbing
Before concrete pour over underground plumbing
Before drywall
4
Rough Framing
After framing complete, before insulation
5
Rough Electrical
After rough framing, before insulation
Before drywall
6
Rough Mechanical
After framing, before insulation
Before drywall
7
Rough Plumbing
After framing, before insulation
Before drywall
8
Insulation / Energy Inspection
After insulation, before drywall
Energy code compliance
9
Drywall/Lath Inspection
After drywall hung but before taping (where required)
Final Electrical
Before occupancy
Before drywall
Final Mechanical
Before occupancy
Before drywall
Final Plumbing
Before occupancy
Before drywall
Final Building
After all other finals passed
CO Issued
Important Notes
24-Hour Notice: Schedule inspections at least 24 hours in advance.
Permit Card: Must be posted and visible from street.
Re-Inspection Fees
- First re-inspection
- Often free
- Second re-inspection
- $50-100
- Additional re-inspections
- Varies
* Fees vary by jurisdiction
Contacts & Resources
Colorado Division of Housing
Denver
Division of Fire Prevention & Control
Lakewood
DORA State Electrical Board
State Building Code Authority
1560 Broadway, Suite 1350, Denver, CO, 80202
Colorado State Plumbing Board
State Building Code Authority
Colorado Energy Office
Denver
1600 Broadway, Suite 1960, Denver, CO, 80202
Contractor Licensing
Contractor licensing in Colorado is managed at the state level. Contact the state licensing board or visit your local building department for specific requirements and license verification.
Data last verified: February 2026 · Always verify requirements with the local building department.