Denver ADU Rules & Requirements (2026)

Denver ADU rules at a glance

Denver's ADU landscape transformed with Colorado HB24-1152 (signed May 2024), a statewide preemption that mandates ADU allowances in all single-family residential zones within qualifying jurisdictions. The law eliminated local owner-occupancy rules, cut parking minimums, and required administrative (ministerial) review for compliant ADU applications.

Detached ADUs up to 864 sq ft are allowed by-right in most Denver zone districts, with some allowing up to 1,000 sq ft. Side and rear setbacks are 5 feet, and the height limit is generally 24 feet (1.5 stories max for detached units). Parking is no longer required for ADUs under the 2024 zoning updates.

Administrative review

Denver uses administrative zoning review combined with building plan check — there is no public hearing for compliant ADU proposals. Typical turnaround is 4 to 8 weeks from application intake to permit issuance. Projects that trigger additional utility service upgrades or that sit in special districts (historic landmark, designated floodplain) may take longer.

Zone-dependent rules

Denver's form-based zoning code means the specific size, height, and lot-coverage rules depend on which zone district your parcel sits in. Urban (U-) zones often allow larger ADUs than suburban (S-) zones. Check the Denver ADU portal and the zoning map for your address to confirm the maximum dimensions.

What Denver does not allow

Short-term rental use on detached ADUs is generally not permitted — Denver's STR ordinance limits licensing to primary residences. ADU-to-ADU sale separation is not allowed; the ADU must remain on the same parcel as the primary dwelling.