Massachusetts Smoke Detector Placement Requirements

All Residences

• Smoke detectors are required on every level of the residence, on the ceiling of the base of each stairway and outside each sleeping area. If a smoke detector is installed within 20 feet of a kitchen or bathroom containing a bathtub or shower, it must be a photoelectric smoke detector. This is due to the fact that ionization smoke detectors can be tripped by steam or cooking fumes.Photoelectric detectors detect smoke accumulation by changes in light levels, while ionization detectors are more sensitive and detect smoke when it interrupts an electrical current in the detector. Most smoke detectors available for purchase include both types of sensors.

Residences Built or Altered Before 1975

• Smoke detectors may be battery powered, hardwired to the building's electrical system or a combination of both.

Residences Built or Altered Between 1975 and August 27, 1997

• Smoke detectors for these residences must be hardwired to the building's electrical system and interconnected. A minimum of one smoke detector is required for every 1,200 square feet of living space.

Residences Built or Altered After August 27, 1997

• Smoke detectors for these residences must be hardwired to the building's electrical system with a battery backup and interconnected. A minimum of one smoke detector is required for every 1,200 square feet of living space.