Brighton council updates ADU setbacks to comply with state law; ordinance passes unanimously

Brighton City Council unanimously approved on Jan. 20 an ordinance amendment that sets rear setback standards for attached accessory dwelling units (ADUs) to match those for detached ADUs and accessory buildings.

Affordable housing coordinator Sean Wyman told council that a June change required by state statute meant attached ADUs needed the same rear setback treatment as detached ADUs; the proposed amendment establishes a 10‑foot rear setback generally and a 5‑foot rear setback when the ADU is accessed from an alley. Wyman said the Colorado Department of Local Affairs (DOLA) reviewed the drafts and found them compliant with state law; approval preserves the city’s eligibility for the state ADU grant program and the Colorado Housing and Finance Authority (CHFA) ADU financing programs.

Councilmembers asked whether attached ADUs are permitted (staff confirmed they were already allowed when subordinate to the principal building), how separation and entrances are handled, and size limits. Staff said attached ADUs must be subordinate in design, have physical separation and a separate entrance; ADU size limits remain in place and an ADU generally cannot exceed the size of the principal building (Wyman referenced a 1,200‑square‑foot cap for certain finished‑basement ADUs).

Councilmember Taddeo moved approval and Councilmember Fiddler seconded; roll call was 9–0. The ordinance proceeds to second reading and will allow Brighton to remain eligible for state ADU funding and financing programs.