ADU rules in Cheyenne

A detached backyard ADU is allowed in every agricultural and residential zoning district in Cheyenne. Table 5-1 of the Unified Development Code lists the use 'Accessory Dwelling' as 'A' (permitted after administrative review) in AG, AR, RR, LR, MR, HR, NR-1, NR-2 and NR-3, plus CBD, MUR and MUB, and as 'P' (permitted by right) in the SS Support Services district; in the form-based code districts Table 7-10 lists it as 'P' in T-1 through T5. UDC 5.7.3(a) allows the unit in 'any permitted accessory building', so a stand-alone backyard cottage or garage apartment is squarely covered. The gate is not a zone gate but a lot gate: UDC 5.7.3(b) allows only one ADU per detached one-unit dwelling lot and prohibits ADUs outright on lots with multi-dwelling buildings, attached dwellings (townhouses) or semi-attached dwellings (duplexes).

Attached and internal ADUs are allowed on the same terms as detached ones, and the code names them explicitly. UDC 5.7.3(a) provides that the unit 'may be in the principal building or any permitted accessory building', and the Article 1 definition of Accessory Dwelling (amended by Ord. 4659, 2-9-2026) says the unit is 'commonly referred to as Basement Apartment or Garage Apartment' and 'may take forms such as a stand-alone unit in an accessory building, a small unit added onto the principal building, or a flat-over-flat duplex'. That last clause is a 2026 change: a stacked two-unit building that used to be classified as a Semi-attached Dwelling is now an Accessory Dwelling, which aligns the zoning code with how the building department already treated it. Basement conversions get the most generous treatment of any ADU type because UDC 5.7.3(e) exempts them from the size cap.

UDC 5.7.3(d): 'In no case shall an accessory dwelling unit be more than 40 percent of the principal dwelling unit up to a maximum of 1,200 square feet', and square footage calculations exclude any related garage, porch or similar area. On a 2,000 sq ft house the binding number is 800 sq ft, not 1,200; the 1,200 sq ft ceiling only becomes the operative limit once the principal dwelling exceeds 3,000 sq ft. UDC 5.7.3(e) carves out basement apartments entirely: 'The unit size limitations shall not apply to basement apartments. The size of a basement apartment may occupy the entire floor area of the existing basement.' For a detached ADU the accessory-building rules in UDC 5.8.8 also bind: no more than two accessory buildings per lot, total accessory footprint no more than 15% of the property area, no accessory building with a larger footprint than the principal building's enclosed footprint, and height 'in no case higher than the principal building' in the standard residential lot types (20 feet for residential accessory buildings on the AG/AR/RR agricultural and rural lot types). Principal dwellings may go up to three stories.

Cheyenne repealed its owner-occupancy requirement on 9 February 2026. Ordinance No. 4659 (case PLTA-25-10) is logged in UDC Appendix K as 'Modifying ADU regulations removing owner occupancy requirements', and the superseded subsection, which read 'The property owner must occupy either the principal unit or the accessory dwelling unit as their permanent residence' (UDC 5.7.3(c) as published in the 3 November 2025 code), is simply gone from the current Section 5.7.3; the remaining subsections were re-lettered. Nothing replaced it, so a non-resident owner may build and rent both the house and the ADU. Wyoming has no statute on the subject either way, so this is purely a local choice. One narrow residual: if the ADU is used as a bed and breakfast, UDC 5.7.9(d) requires the business owner to keep a permanent residence in either the principal dwelling or the ADU.

UDC 5.7.3(h): 'One parking space shall be provided in addition to that which is required for the principal dwelling.' Table 6-2 sets the principal detached dwelling at 2 spaces per dwelling unit, so a house with an ADU carries 3 spaces total. The same February 2026 ordinance that dropped owner occupancy also loosened this clause: the prior text (UDC 5.7.3(i), November 2025) required 'One off-street parking space ... and it shall be located on a discrete portion of the lot', and both the word 'off-street' and the discrete-location requirement were deleted. The on-street parking credit in UDC 6.2.6(a) then gives 'one credit for every on-street parking space abutting the lot', and UDC 6.2.4(b)(1) lets the Director shave up to 10% of required parking; in a historic district, parking may be reduced by 50% through an Administrative Adjustment under UDC 6.2.4(b)(2).

Staff-level approval, no public hearing. Table 5-1 marks Accessory Dwelling as 'A', meaning 'permitted after administrative review', in every agricultural and residential district. Under the Administrative Use Approval procedure in UDC 2.2.5 the applicant holds one pre-application conference, staff has 7 days to declare the application complete, 'Posted Notice. Not Required.', and 'between 7 and 15 days of the determination of a complete application, the Director shall take one of the following actions: (1) Approve the application; or (2) Deny the application and state the specific reasons for denial.' The Director's decision is final and appealable to the Board of Adjustment. It is not a rubber stamp: staff applies compatibility criteria on building scale, form, landscape and operating characteristics, so a denial is possible. After approval, UDC 5.7.3(c) requires the owner to record a 'Notice of ADU Regulations' with the Laramie County real estate office. A building permit follows; since Cheyenne zones under W.S. 15-1-601 and has adopted the 2024 International Residential Code (Cheyenne Municipal Code 15.10.010, Ord. No. 4613, 2-24-25), the state Fast Track Permits Act now puts a shot clock on that building permit.

Since Ord. 4659 removed owner occupancy on 9 February 2026, an ADU may be rented long term with the owner living anywhere, and neither the UDC nor the Cheyenne Municipal Code imposes any rental registration, rental licensing or primary-residence test (a chapter-by-chapter sweep of all eleven titles of the municipal code on 2026-08-04 found no short-term rental, vacation rental or rental-registration chapter). Short-term nightly rental is not a listed use anywhere in the UDC use tables, so it is not an allowed use in its own right; the only lawful nightly-lodging pathway in a house or ADU is 'Lodging, Bed and Breakfast', which UDC 5.7.9 limits to 6 guest rooms, bars kitchen or cooking facilities in guest rooms, requires that 'The owner of the business shall maintain a permanent residence in either the principle dwelling unit or accessory dwelling unit', and provides that 'Guests must pay on the basis of a daily rental rate, and must limit their stay to 14 consecutive days'. A city bed and breakfast license under Municipal Code Chapter 5.28 is also required, and for a 'bed and breakfast facility' that chapter states 'Residence in the home by the licensee is a requirement'. The ADU cannot be sold off separately: UDC 5.7.3(b) ties it to the principal detached one-unit dwelling lot, and the recorded 'Notice of ADU Regulations' runs with the property.