As of APRIL 1, 2011 – When conveying fee title or transferring possession under a land sale contract of a one and two family dwelling or multifamily housing that contains a CARBON MONOXIDE source, the dwelling or housing must have one or more properly functioning carbon monoxide alarms installed in locations that provide carbon monoxide detection for all sleeping areas. All rental dwelling units that have a carbon monoxide source or are located within a structure having a carbon monoxide source are required to have a carbon monoxide alarm.