Vermont Statutes Annotated (VSA) Title 9, Chapter 77 § 2881-2883:
New and existing (upon sale) residential dwellings must have one or more CO detection devices in the vicinity of bedrooms (for residential dwellings), installed per the manufacturer’s instructions. (Effective date: July 1, 2005)

Vermont Division of Fire Safety – Information on Carbon Monoxide 
Group R occupancies (e.g., hotels, motels, dormitories, and dwelling units within apartment buildings) are required to install CO alarm or detectors. (Effective date: November 5, 2012)

Vermont Statutes Annotated (VSA) Title 20 Chapter 173 Section 2729
Any multiple unit dwelling, including lodging establishment, shall be provided with one or more CO detectors. (Effective July 1, 2005)