Cheyenne, WY Accessory Structures: ADU Rules (2026)
ADU rules in Cheyenne, WY, also called accessory dwelling unit regulations or granny flat ordinances, cover setbacks, owner-occupancy, parking, and permit requirements.
Key Facts
- Max size
- 40% of main home, 1,200 sq ft cap
- Units per lot
- One ADU per detached lot
- Basement apartments
- Exempt from size cap
- Required filing
- Notice of ADU Regulations recorded
- Where allowed
- Only zones permitting ADUs
Summary
Cheyenne caps accessory dwelling units at one per detached single-unit lot, limited to 40% of the main home's size or 1,200 square feet.
Only one accessory dwelling unit is permitted per detached one-unit dwelling lot in any zoning district where accessory dwellings are allowed as permitted, administrative or conditional uses. Accessory dwelling units are prohibited on lots with multi-dwelling buildings, attached dwellings or semi-attached dwellings.
c. After approval by the Director of an accessory dwelling unit pursuant to subsection (b) of this section, the property owner will record with the Laramie County real estate office a “Notice of ADU Regulations” that shall contain a legal description of the subject property. The “Notice of ADU Regulations” shall be in a form approved by the Director prior to filling.
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. This limitation is in addition to all other lot and building standards applicable in the district. Square footage calculations, as contained herein, exclude any related garage, porch, or similar area.
e. 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.
f. The accessory dwelling unit shall not include any design elements on principal or accessory buildings that alter the character of the lot, building type or district in general.
Full Breakdown
Where zoning allows accessory dwelling units, Cheyenne's Unified Development Code lets an ADU sit inside the main house or in a permitted accessory building, but only one is allowed per detached one-unit dwelling lot and ADUs are barred outright on lots with multi-dwelling, attached, or semi-attached buildings. The unit can't exceed 40 percent of the principal dwelling's size, capped at 1,200 square feet (garage, porch, and similar space don't count toward that figure), though basement apartments are exempt from the size cap entirely. Once the Director approves an ADU, the owner must record a 'Notice of ADU Regulations' with the Laramie County real estate office.
Violations & Fines
Building or operating an ADU beyond the size cap, adding a second ADU on a detached lot, or placing one on an ineligible multi-dwelling or attached-dwelling lot is a zoning violation subject to code enforcement.
Frequently Asked Questions
Can I build more than one ADU on my Cheyenne lot?
How big can a Cheyenne ADU be?
Sources & Official References
Other rules in Cheyenne
How Cheyenne compares: Easiest Cities to Build an ADU·Compare Cheyenne to another location·View the Wyoming accessory structures overview
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