Wyoming's no state income tax policy and Jackson Hole luxury market create unique ADU opportunities. Here's what ADUs cost across Cheyenne, Casper, Jackson, and statewide.
Wyoming has not passed a statewide law requiring cities to allow ADUs — whether you can build one, and under what size and parking rules, is set entirely by your city or county. That changes for permit timing, though: HB0002 (Enrolled Act No. 16, 2026), effective July 1, 2026, requires local governments to notify applicants within 10 business days if a residential building permit application is incomplete, and to approve or deny it within 30 calendar days — after which the application is automatically deemed approved as submitted. It applies to dwellings of 3 stories or fewer under 3,000 sq ft per unit, which covers most ADUs. Separately, Wyoming's 2026 Homestead Opportunity Program (HB0055) distributes low-cost land for starter homes but actually restricts ADUs on its own program parcels — it's not a general ADU law and doesn't apply to a typical existing property. The detailed figures below are representative planning ranges, not a statewide fee schedule or review-time guarantee.
No statewide law requires Wyoming cities to allow ADUs. HB0002 (2026), effective July 1, 2026, does set a hard statewide permit-review deadline: 30 days to approve or deny a qualifying residential permit, or it's deemed approved automatically.
Source: Wyoming Legislature — HB0002 (Enrolled Act No. 16) →
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.
A separate structure on the lot — highest cost, highest value. Jackson/Teton County's resort economy pushes this to the top of the range; Cheyenne and Casper sit toward the bottom. Whether a detached ADU is allowed at all is set by your city or county, since Wyoming has no statewide ADU siting mandate.
Detached ADU Guide →An addition sharing one wall with the main house — typically 20–35% less than detached construction. A strong option on smaller lots where a detached structure isn't feasible.
Attached ADU Guide →The most affordable Wyoming ADU option, using an existing structure. Cost-effective statewide, converting 40–55% less than a comparable detached new build with similar rental income.
Garage Conversion Guide →Wyoming's 36–48-inch frost depth means many homes already have full basements — a genuine year-round build option. Egress windows are required.
Basement ADU Guide →Factory-built construction offers the fastest timeline of any ADU type — a real advantage where labor availability is a constraint in more remote Wyoming markets.
Prefab ADU Overview →The smallest footprint option, converted within the existing home. The lowest entry cost of any ADU type, though rental income is correspondingly modest.
Junior ADU Overview →
*Sheridan's range is extrapolated from statewide construction-cost data at a representative build size rather than city-specific permit records; verify against local bids before publishing final figures. Gillette (energy-sector economy) and Cody (Yellowstone gateway) are additional markets not pictured here — each has a distinct cost profile worth checking with local contractors directly.
Local control: Local rules control. No broad statewide ADU siting mandate was identified in this review. Jackson Hole's resort economy pushes its rules and costs well past Cheyenne's and the state's other cities. Permit fees and review timing remain planning estimates until confirmed for the specific property.
Calculate My ROI →These moves push savings further and prevent the most common costly mistakes homeowners make on Wyoming ADU projects.
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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