ADU rules in Durango

Detached ADUs (a unit inside an accessory building, including above a garage) are allowed in the EN-1 Old Durango, EN-2 2nd and 3rd Avenues, EN-3 East Animas City, EN-MF Multifamily, RA Rural/Agriculture, RL Residential-Low, RM Residential-Medium, RH Residential-High and MU-N Mixed-Use Neighborhood districts, and are flatly Not Allowed in EN-4 Crestview and Needham, EN-5 Riverview and EN-6 Other Single-Family Neighborhoods. The city explains that prohibition as the absence of alleys in those districts, which it treats as essential emergency-service access. Every detached ADU still needs a Limited Use Permit, must sit on the rear half of the lot in every zone except RA, must take vehicular access from an alley where one exists, and is capped by the height and setback figures in Table 2-3-2-3B. Minimum parcel areas for detached ADUs were eliminated by a Land Use and Development Code amendment that took effect 2/28/2026.

Durango calls attached and internal units 'integrated ADUs', defined as units created by dividing space within a principal building or by adding floor area to an existing building, and Table 2-3-2-3A lists integrated units as Allowed in all twelve districts where ADUs exist at all: EN-1 through EN-6, EN-MF, RA, RL, RM, RH and MU-N. A basement conversion is the cleanest path, since ADUs located entirely in basements escape the 550 square foot floor-area cap. The unit must not read as a second dwelling from the street: no external stairs to a second-story integrated ADU, exterior doors configured like normal secondary entrances, and any addition must match the principal home's siding, roofing, windows, trim and roof pitch. For new construction, an attached or integrated ADU must share at least 25 percent of the combined length of its first-floor exterior walls with the principal structure, and a breezeway does not count. A Limited Use Permit is still required.

Both integrated and detached ADUs are capped at 550 square feet of floor area, measured as the enclosed interior area of the unit; porches, decks, and space used for other purposes such as a detached garage or workshop do not count, and stairwells and landings serving a second-story ADU do not count unless they hold usable space for the ADU occupant. Two escapes exist: an ADU located entirely in a basement is not subject to the 550 square foot limit at all, and an ADU converted entirely from existing living space inside a single-family home may request a larger cap through Alternative Compliance if existing framing, foundations or walls make 550 square feet impractical. Detached ADU buildings are separately capped by Table 2-3-2-3B at 20 feet to the peak and 13 feet 6 inches to the plate in most zones, and 18 feet and 11 feet 6 inches in RL. Buildings containing ADUs still count toward the lot's building coverage and floor area limits, although an ADU sharing a building with a detached garage may use the 450 square foot detached garage floor-area bonus.

Either the principal residence or the ADU must be owner-occupied, and only one of the two units may be rented to a non-owner. Before the city approves the ADU the owner must record a notarized owner-occupancy affidavit with the Community Development Department, and the city's ADU page states the affidavit must be renewed every two years (the code calls this biannual recertification). A buyer of a home with an ADU must file a new notarized affidavit within 60 days of purchase. The Administrator may waive owner occupancy for a temporary absence of two years or less with acceptable proof of absence from the Durango area, plus one extension of up to a year, and in extreme circumstances the Community Development Commission may allow up to five years, during which both units may be rented. If the requirement lapses, the owner must vacate or remove the ADU and return the property to single-family status. Colorado's HB24-1152 bars owner-occupancy mandates, but only in 'subject jurisdictions', and Durango is not one (see caveats), so the local requirement stands.

One off-street parking space must be provided for the ADU on top of the parking required for the principal building, which for a single-family detached home is two spaces under Table 4-5-2-2A. Existing required off-street parking must be retained, though it may be reconfigured. Where the parcel has no parking at all, the code sets the total at two off-street spaces, one for the ADU and one for the principal dwelling. The total may be reduced by one space if the owner demonstrates the lot is within 300 feet of a local street that is not an emergency snow route, allows on-street parking, and is paved wide enough for two drive lanes plus on-street parking, subject to Community Development Department verification. Tandem parking counts, but no more than one tandem space may be used to meet the property's requirement, and every space must be in a garage or hard-surfaced with asphalt, concrete or another material the City Engineer approves.

An ADU is a 'major accessory use' that requires a Limited Use Permit before construction. Durango's Limited Use Permit is administrative: Table 6-3-2-2 lists it as issued by the Administrator, and Sec. 6-3-2-2.A states administrative approvals are issued without a requirement for a public hearing, with the decision due within 30 calendar days of a complete application. It is nonetheless discretionary rather than by right, which is why this field is not marked 'permitted': under Sec. 2-2-2-1 staff must find the ADU will not conflict with adopted City plans and is compatible with surrounding land uses and the character of the immediate area. The application triggers a 14-day notice posted on the property and mailed notice to owners within 300 feet, both starting five days after the application is complete, plus a 15-day public comment period. A pre-application meeting is required, the fee schedule is set by the city, and staff decisions may be appealed under Division 6-3-17. A building permit is separately required for any structure 120 square feet or larger.

Long-term renting works, with one limit: only one of the two units on the lot may be rented to a non-owner, because the other must be owner-occupied. Short-term renting does not: Sec. 2-2-3-4.G states plainly that vacation rental homes are not permitted on properties with Accessory Dwelling Units. Durango defines a vacation rental as a dwelling rented for 1 to 29 days, requires its own Limited Use Permit plus a business license, sales tax license and lodgers tax license, allows them only in EN-1, EN-2, CB, MU-N, MU-A and qualifying Planned Development zones, and caps them at 22 permits in EN-1 and 17 in EN-2 (both effectively full, with a waitlist). Rentals of 30 days or longer are not vacation rentals and are not regulated as such. The only other short-term option in the code, a Short-Term Room Rental under Sec. 2-3-2-5, is limited to one bedroom inside a single-family detached home in the RA Rural/Agriculture district, requires the homeowner to be present on site during the rental, and is not available in an ADU. Separately, an owner who takes the city's ADUs for Locals rebate must lease the ADU to someone working at least 32 hours a week for a La Plata County employer on a lease of at least six months.