Maryland Public Safety Section 9-103

      (a)      At least one smoke detector shall be installed on each level, including a basement but excluding an attic, of each new residential dwelling unit:

            (1)      that contains alternating current (AC) electrical service;

            (2)      that is classified residential, as defined in the most recent edition of the National Fire Protection Association Life Safety Code adopted by the State Fire Prevention Commission; and

            (3)      for which a building permit is issued for new construction on or after January 1, 1989.

      (b)      If two or more smoke detectors are required under subsection (a) of this section, the smoke detectors shall be of a type and installed in a manner so that activation of one smoke detector causes activation of all other required smoke detectors in the residential dwelling unit.

      (c)      A smoke detector required under this subtitle shall operate both by battery and on an alternating current (AC) primary source of electric power if the smoke detector is installed in a new residential dwelling unit:

            (1)      that contains alternating current (AC) electrical service;

            (2)      that is designed to be occupied by one or more families; and

            (3)      for which a building permit is issued for new construction on or after July 1, 1990.

      (d)      This section:

            (1)      may be enforced by a county fire chief, fire administrator, or municipal fire chief; and

            (2)      does not prevent a county from enacting more stringent laws that relate to smoke detectors.