Boulder, CO Accessory Structures: ADU Owner Occupancy (2026)

Before March 2025, Boulder's land use code conditioned ADU permits on the property owner living in either the principal dwelling or the ADU itself — a long-standing requirement intended to limit absentee speculation. The February 2025 reform package adopted by City Council and codified in BRC 9-6-3(n) struck the owner-occupancy clause, aligning Boulder with Colorado HB24-1152 (codified at C.R.S. 29-32-101 et seq.). Under the state statute, applicable to subject jurisdictions including Boulder, local governments may not impose owner-occupancy requirements as a condition of constructing or operating an ADU. The Boulder rule applies prospectively to any ADU proposed on or after March 8, 2025 but the state statute's preemption reaches existing ADUs as well, so the city does not enforce legacy owner-occupancy conditions on previously permitted ADUs. Deed restrictions tying ADUs to owner occupancy are no longer recorded at permit issuance. A separate, optional deed restriction allows a larger ADU (up to 1,000 sf detached or 1,200 sf attached) in exchange for restricting rents to households at or below 75% AMI — this is a voluntary affordability bonus, not an owner-occupancy mandate. Boulder's separate Rental Housing License (BRC Title 10 Chapter 3) still applies to any unit rented for 30+ days, regardless of owner residency.