ADUs in Steamboat Springs: Benefits, Rules, & Properties Available

Yes, you can build an accessory dwelling unit in Steamboat Springs, though the city refers to them by another name: secondary units. Secondary living spaces have broad appeal as buyers seek options for multi-generational households, adult children moving back to the valley, aging parents, guest housing on ranch properties, and additional revenue streams. In Steamboat and Routt County, secondary units, like a detached suite over the garage or a backyard cottage, are subject to their own city and county guidelines. For example, nightly rentals are not permitted in secondary units; only long-term rentals of 30 days or more are permitted per city and county code. Understanding how these ADUs or secondary units work and where the benefits apply is helpful in the real estate process. Here, we outline the key highlights and properties with secondary units now available.

Key takeaways

• Within Steamboat city limits, a secondary unit is capped at 650 square feet. It cannot be rented nightly, but it can be rented long-term, defined by city code as 30 days or more. (Source: City of Steamboat Springs Ordinance No. 2888)

• Colorado's 2024 statewide ADU law (HB24-1152) does not apply to Steamboat Springs. The city sets its own rules. (Source: Colorado Dept. of Local Affairs, dlg.colorado.gov, current list as of August 2026)

• Guest houses on ranch and large-acreage properties in unincorporated Routt County fall under separate county zoning, but short-term rentals are prohibited countywide except in commercially zoned areas or on properties with a bed-and-breakfast or guest-ranch permit. A secondary dwelling unit (SDU) or accessory dwelling unit (ADU) is generally limited to 850 square feet of habitable space if it has fewer than two bedrooms, or up to 1,000 square feet if it has two or more bedrooms. (Sources: Routt County Planning Department and Routt County Short-Term Rentals guidance)

• Multi-generational living and long-term rental income are the reliable use cases for a secondary living space across both jurisdictions. Short-term rental income is not.

• Rules like these get updated. Always confirm current zoning and rental regulations with the city or county before buying or building.

What Steamboat Calls a Secondary Unit

According to the City of Steamboat Springs, "secondary unit" is the umbrella term for what's known elsewhere as a granny flat, in-law suite, or accessory dwelling unit: an independent living space with its own sleeping area, bathroom, and kitchen, located on the same lot as a primary residence. To qualify, a lot has to meet the minimum size required for a single-family home plus a secondary unit in its zone district, and the structure has to meet standard setbacks (commonly 5 to 10 feet on the sides and 15 to 20 feet in front, though this varies by parcel). The city caps a secondary unit at 650 square feet, regardless of lot size or zone district. Per the city's secondary unit submittal requirements, anything built after February 13, 2009 also needs a certificate of occupancy confirming it meets current building code, which is worth checking before buying a property that already has one.

Can You Nightly Rent a Secondary Unit?

No. This is the detail that surprises the most buyers. According to the City of Steamboat Springs Planning and Community Development Department, a secondary unit cannot be rented on a nightly basis, even on a lot inside the Green Zone where the primary residence may be eligible for short-term rental. It can be rented long-term (30 days or more, per city code), used for family, or set up as a caretaker's residence. The same holds outside city limits. Unincorporated Routt County, where most of the ranch communities sit, prohibits short-term rentals altogether except in commercially zoned areas or on properties with a bed and breakfast or guest ranch permit, according to Routt County's short-term rental guidance. A detached guest house on a ranch parcel serves the same long-term uses as a secondary unit in a city. It just isn't capped at 650 square feet. According to the Routt County Planning Department, secondary dwelling unit (SDU) or accessory dwelling unit (ADU) is generally limited to 850 square feet of habitable space if it has fewer than two bedrooms, or up to 1,000 square feet if it has two or more bedrooms.

Does Colorado's Recent ADU Law Change Anything Here?

Not currently. House Bill 24-1152, passed in 2024, requires certain Colorado municipalities to allow at least one ADU on single-family lots and removes some of the barriers those cities previously imposed. But according to the Colorado Department of Local Affairs, the law only applies to "Subject Jurisdictions," defined as municipalities of 1,000 or more residents located within a metropolitan planning organization boundary. Steamboat Springs is not on the state's current list of Subject Jurisdictions. The city's own code, including the 650-square-foot cap and the no-nightly-rental rule, stands on its own.

Properties with ADUs or ADU Option Available Now

42375 River Drum Trail at Marabou Ranch

This private estate on 6.78 acres in Marabou Ranch features a 7,201-square-foot, six-bedroom main residence with a private two-bedroom guest suite, while a fully detached two-bedroom guest house, complete with its own kitchen and two-car garage, sits separately on the property. , Owners at Marabou enjoy access to two miles of private Elk River frontage, the Master Guide Program, the River House Lodge, and a private club at the base of the Steamboat Ski Area. Represented by Chris Paoli. View Listing →

26000 High Ridge Drive at Deerwood Ranches

This 35.88-acre estate pairs a 5,213-square-foot, five-bedroom main residence, designed by architect Michael Olsen with 27-foot vaulted ceilings and a hand-stacked stone fireplace, with a caretaker or guest apartment set above the four-car garage. That apartment comes fully equipped with its own kitchen, bedroom, full bath, two-sided gas fireplace, and mountain views, functioning as a separate living space. Located within the Steamboat Springs School District, the property also includes a private HOA trail system for horses, hiking, and biking. Represented by Chris Paoli. View Listing →

27000 Fire Song Road at Marabou Ranch

This private homesite at Marabou Ranch is one of the few within the community's gates approved for an accessory dwelling unit, a rare designation inside a shared ranch of 62 homes and homesites across more than 1,700 acres. The 6.67-acre parcel already has private water and power extended to the lot line, so a buyer moves directly from vision to construction. Ownership includes use of Marabou's guest cabins, a great amenity to stay onsite while the home is under construction, plus all of Marabou’s private amenities. Represented by Chris Paoli. View Listing →

Acanthus Estate at Catamount Ranch & Club 

33560 Catamount Drive spans nine acres above the 10th fairway with sweeping views of the South Valley, Steamboat Ski Area, and Flat Top Mountains. Architect Bill Rangitsch designed the 10,746-square-foot residence around a timber-truss great room with two-story windows, and Miami-based B. Pila Design furnished the home entirely, with furnishings included in the sale. Private quarters hold a self-contained, 1,500-square-foot upper-level apartment with two bedrooms and two baths, giving extended family or guests real independence and privacy. Represented by Chris Paoli and Noah Zedeck. View Listing → 

Silver Fox Lodge

33750 Sky Valley Drive sits on 3.51 wooded acres bordering more than 10,000 acres of U.S. Forest Service land, with eight all-ensuite bedrooms across 8,205 square feet built for hosting at scale. A dual kitchen with multiple refrigerators, ranges, and dishwashers, along with a four-car garage and additional RV parking, reflects a home designed for large groups and extended stays. For buyers interested in adding a dedicated secondary structure, the adjacent homesite is available for separate purchase, opening the door to building a standalone ADU rather than converting existing square footage. Represented by Lee Calihan. View Listing →

For more on a specific property, or to talk through which type of secondary living space fits your plans, connect with The Agency Steamboat Springs at [email protected].