ADU Laws in Colorado (2026)
Colorado state ADU law details, key provisions, preemption status, and recent legislative changes for accessory dwelling units.
Law Name
Colorado House Bill 24-1175 — Accessory Dwelling Unit Zoning
Effective Date
2024-08-07
Preempts Local Ordinances
Yes — state law overrides local restrictions
Has State Law
Yes
Key Provisions
Requires all Colorado municipalities with population over 1,000 to allow at least one ADU per single-family residential lot by-right
Prohibits minimum lot size requirements specifically targeting ADU prohibition — local minimum lot size cannot exceed the zone's standard minimum
Limits off-street parking requirements for ADUs — no additional parking required for ADUs within 0.25 miles of a high-frequency transit stop
Requires ministerial (administrative) ADU approval — no discretionary design review for ADUs meeting objective standards
Municipalities may not require owner-occupancy as a condition of ADU approval
Creates a state enforcement mechanism through the Colorado Department of Local Affairs (DOLA)
Municipalities had until July 1, 2025 to update their development codes to comply
Applies to all counties with unincorporated areas with population over 1,000 as well
Legislative History
2024 — HB 24-1175
Comprehensive ADU reform legislation signed into law August 7, 2024. Requires all Colorado municipalities over 1,000 population to allow ADUs by-right on single-family lots, removes minimum lot size barriers, limits parking mandates near transit, prohibits owner-occupancy requirements, and establishes state enforcement through DOLA. Local compliance required by July 1, 2025.
2024 — HB 24-1174
Companion middle housing legislation requiring cities with 5,000+ population to allow at least 2 units per single-family lot. Alongside HB 24-1175, significantly expands housing options in Colorado. Referred to as the 'missing middle housing' bill.
Official Sources
What Does Preemption Mean for Local Cities?
Because Colorado law preempts local ordinances, individual cities cannot impose restrictions stricter than the state standard. A city may still have additional administrative requirements, but cannot deny ADU applications that comply with state minimums.
Learn about Coloradozoning preemption →Source: Colorado House Bill 24-1175 — Accessory Dwelling Unit Zoning. Last verified April 5, 2026. View source