Colo. Rev. Stat. § 38-45-101 to -106:
New and existing single- and multi-family dwellings that contain fuel-burning appliances, fireplaces, and/or attached garages must be equipped with CO alarms placed within 10 feet of sleeping areas. (Effective date: July 2009)

8 CCR 1302-7 (pg 23):
Manufactured Housing: An approved carbon monoxide alarm shall be installed outside of each separte sleeping area within 15 feet of the bedroom.