Carbon Monoxide Alarms are mandatory in all homes. On October 15th, a new law in Ontario was passed that requires Carbon Monoxide detectors in all buildings where people sleep. Gravenhurst Fire Prevention Officer, Robert King says the new law will be phased in over the next year. King says homes that currently have a carbon monoxide alarm in place, must comply with the new maintenance and testing requirements. If you not, all CM detectors are required to be in homes, apartments and buildings by April 15, 2015 and must be adjacent to each sleeping area of the home.