City-by-city ADU cost data across Colorado's major markets. Built from permit records, contractor data, and regional labor rates.
Effective framework: HB 24-1152. Covered “subject jurisdictions” must provide an administrative ADU approval path. The law does not apply identically to every Colorado locality. Permit fees and review timing remain planning estimates until confirmed for the specific property.
Calculate My ROI →Freestanding backyard structure. Most Colorado municipalities require the ADU to match or complement the primary residence in materials, roof pitch, and finish. Boulder and Fort Collins push toward the top of this range.
Detached ADU Guide →A new addition connected to the main home, such as a ground-floor suite or a converted garage with the interior door sealed off. Shared utility connections reduce hookup costs versus a fully detached unit.
Attached ADU Guide →A converted garage with the interior door to the main house sealed off, classified as an attached ADU under Colorado law. One of the most cost-efficient paths to an ADU along the Front Range.
Garage Conversion Guide →An internal ADU — a basement conversion, attic buildout, or repurposed floor space. Some municipalities, including Golden, allow whole-floor internal conversions without a hard square footage cap.
Basement ADU Guide →Compact prefab models (roughly 597–848 sqft) are increasingly common along the Front Range, engineered for Colorado's high-altitude climate and snow loads.
Prefab ADU Overview →A converted interior space within the existing home footprint, with its own private entrance — often the most HOA-compatible and cost-effective ADU option in Colorado.
Junior ADU Overview →
*Total-cost ranges outside Denver are derived from regional construction-cost data at a representative ~650 sq ft build; verify against local bids before publishing final figures. Boulder and Fort Collins genuinely run above Denver on cost — this is a sourced market condition, not an error.
Covered “subject jurisdictions” must provide an administrative ADU approval path. The law does not apply identically to every Colorado locality. The detailed figures below are representative planning ranges, not a statewide fee schedule or review-time guarantee.
Covered “subject jurisdictions” must provide an administrative ADU approval path. The law does not apply identically to every Colorado locality.
These are planning benchmarks, not a permit quote, eligibility ruling, or legal opinion. Confirm zoning, building, utility, site, private-covenant, fee, and timing requirements with the current local authorities. See the 51-jurisdiction law directory and national permit guide.
HB 24-1152 already guarantees your administrative right to build in most Front Range cities. These moves target the design, altitude, and timeline factors that remain.
Calculate My ADU ROI →
Illustrative 1-bedroom layout. Actual floor plans vary by ADU type, size, local code, and homeowner needs.
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