ADU rules in Greeley

Detached ADUs (garage apartments, backyard cottages, 'granny flats') are an allowed accessory use under Sec. 24-403.b in the zoning districts where Table 24-4-2 marks 'Accessory dwelling unit' as permitted: R-M (Residential Medium Density), R-H (Residential High Density), C-L and C-H (commercial), and MU-L and MU-H (mixed-use). One ADU is allowed per lot, and only with a detached house or a duplex/multi-unit house. The table leaves ADUs blank (not permitted) in R-E (Residential Estate) and R-L (Residential Low Density) even though detached houses are permitted there; since June 30, 2025 state law (C.R.S. 29-35-403(1), HB24-1152) requires Greeley to allow one ADU wherever single-unit detached dwellings are allowed, and the city's conforming code update was still unadopted as of July 2026, so see caveats for those districts.

ADUs may be located within the principal building, such as an attic or basement apartment (Sec. 24-403.b.2), and the use definition in Sec. 24-402.b likewise covers units in the same building as the principal dwelling. Internal and attached ADUs follow the same district list as detached ones (Table 24-4-2: permitted in R-M, R-H, C-L, C-H, MU-L, MU-H), so the same R-E and R-L gap and the HB24-1152 override described in the caveats apply.

Sec. 24-403.b.3 caps an accessory dwelling at 60 percent of the living area of the principal dwelling or 1,200 square feet, whichever is less. A detached ADU building must also meet the secondary-building limits of Table 24-5-2 (Sec. 24-502.c): footprint up to 50 percent of the principal building footprint with a 1,200 square foot maximum, height up to 25 feet but no taller than the principal structure, 5 foot side and rear setbacks, and placement at least 12 feet behind the front building line; buildings over 12 feet tall or 250 square feet must meet residential design standards. For small principal homes the 60 percent rule can fall below the 500 to 750 square foot window that HB24-1152 protects, in which case state law overrides the local cap (see caveats).

The ADU standards in Sec. 24-403.b (one per lot, size, parking, compatibility and subordination) contain no owner-occupancy requirement, and no other Development Code provision imposes one on ADUs. State law reinforces this: C.R.S. 29-35-403(2)(b) (HB24-1152) prohibits subject jurisdictions like Greeley from requiring an ADU, or any other dwelling on the same lot, to be owner-occupied; the city may at most require proof that the owner resides on the parcel when an application is submitted to build or convert an ADU, or for a short-term rental license.

Table 24-7-3 (Required Parking, Sec. 24-703.a) lists 'Secondary dwelling' at 1 space per bedroom; that row is the parking rate for the accessory dwelling (the only place the code uses the term). Sec. 24-403.b.4 adds that all parking necessary for the ADU must meet neighborhood design standards and be confined to the garage, driveway, or the street directly in front of the dwelling. These provisions predate HB24-1152: since June 30, 2025, C.R.S. 29-35-403(2)(a) and (3) forbid requiring construction of a new off-street space for an ADU unless the lot has no usable existing off-street space, is in a district that required parking for the primary dwelling as of January 1, 2024, and is on a block where on-street parking is prohibited; the city may still require designating an existing driveway, garage, or tandem space for the ADU.

In the districts where Table 24-4-2 allows them, ADUs carry a P designation: permitted uses are 'subject to staff review and/or site plan approval to confirm compliance with general district and building standards applicable throughout this code' (Sec. 24-402.a.1(a)). No public hearing or use-by-special-review process applies to ADUs in any district (S uses go through Sec. 24-206; the ADU row has no S entries), so approval is administrative through planning staff review and a building permit. HB24-1152 likewise requires subject jurisdictions to approve ADUs through an administrative process.

Nothing in Sec. 24-403.b restricts renting an ADU on a long-term basis and there is no owner-occupancy condition attached. For stays under 30 days, 'Lodging, short-term rental' (defined in Sec. 24-402.b as the rental of a dwelling unit, or portion thereof, for less than one month) is itself a permitted use in every residential district in Table 24-4-2, including R-E, R-L, R-M, R-H and R-MH. Greeley has no dedicated short-term rental licensing ordinance; per the city's sales tax FAQ (greeleyco.gov), STR operators must obtain a business license and collect Colorado sales tax (2.9 percent), Greeley sales tax (4.11 percent), and Greeley lodging tax (3 percent), a combined 10.1 percent.