Boulder, CO Rental Property Rules: Rental Registration (2026)

Chapter 3 of Title 10, Boulder Revised Code 1981, sets up the city's rental license system, and Section 10-3-2(a) is the operative registration rule: no operator may allow, or advertise to allow, anyone to occupy a dwelling, dwelling unit, or rooming unit as a tenant for valuable consideration unless the property already holds a valid rental license issued by the city manager. An operator can advertise a rental of 30 days or longer before the license issues only if a complete rental licensing application has been submitted, or the ad is for pre-leasing new construction, and any advertisement must carry the assigned rental license number.

Section 10-3-2(b) carves out four exemptions from the registration duty: an owner-occupied unit housing unrelated roomers, a unit that is the owner's principal residence temporarily rented for no more than 12 consecutive months in any 24-month period while the owner lives outside Boulder County, commercial hotel and motel stays under 30 days (though bed and breakfasts still need a license), and common areas of buildings with individually owned units. Even an exempt operator must first file an Affidavit of Exemption with the city manager before letting anyone occupy the space.

Once licensed, a standard rental license runs four years from issuance, or until the property changes ownership, under Section 10-3-3(a). Renting without the required license, or violating any provision of Chapter 3, carries a fine of at least $500 and not more than $2,000 per violation, or up to 90 days in jail, or both, under Section 10-3-17(a).