Maryland law requires all newly constructed homes to have a smoke alarm in each sleeping room, one outside each sleeping room and one on every level of the home/dwelling. Existing homes are required to have one on every level of the home including basements. Fires spread rapidly, leaving only a few minutes, often less than 2:30 to evacuate before conditions may make it impossible to evacuate. Without an alarm on every level, it is very possible a fire could go undetected until it is too late.