MA Smoke Detector Law

Smoke detectors are an important home safety feature. It’s also legally required in Massachusetts, although inspections only take place when a property is sold. Single family and multi-family homes sold in the state of Massachusetts must be inspected by the local fire department. A smoke certificate is required at closing. MA smoke detector law actually requires different types of smoke detectors in different areas of a home.

Ionization vs. Photoelectric Smoke Detectors

Ionization Smoke Detectors

Ionization smoke detectors have two electrodes with a current running between them. When smoke is present, it blocks this current and sounds the alarm. This type of smoke detector is good for flaming fires but it can’t tell the difference between smoke and steam. This is why smoke detectors may be triggered when you are cooking.

Photoelectric Detectors

Photoelectric smoke detectors have a light beam (instead of a current). Smoke or fire can interfere with this beam and trigger the alarm. This type of smoke detector is best at detecting smoldering fires. It is also less likely to be triggered by steam from cooking.

Overview of MA Smoke Detector Law

MA smoke detector law defines where you must place smoke detectors in your home and what types of smoke detectors should be used. Requirements vary slightly depending on when your home was built or renovated (some leeway is given to older homes). Given that ionization smoke detectors are prone to false alarms, photoelectric detectors are required near kitchens and bathrooms. Here’s a chart that may help.

Placement	before 1975	1975 to Aug. 27, 1997	after Aug. 27, 1997	on or after Jan. 1, 2008	on or after Feb. 4, 2011
Power Supply	Hardwired or Battery	Hardwired Inter- connected	Hardwired Inter- connected Battery Backup	Hardwired Inter- connected Battery Backup	Hardwired Inter- connected Battery Backup
Every Level of Living	Y	Y	Y	Y	Y
Bottom of Each Stairwell	Y	Y	Y	Y
Outside Every Sleeping Space	Y	Y	Y	Y	Y
Min. 1 for Every 1,200 sq.ft. Finished Space per Level		Y	Y	Y	Y
Inside All Bedrooms			Y	Y	Y
In Basement					Y
Bottom of Every Stairwell to a finished level					Y
Within 20ft. of Kitchens/Baths	Photoelectric		Photoelectric	Photoelectric	Photoelectric
Outside of 20ft. of Kitchens/Baths	Both Ionization & Photoelectric			Photoelectric OR Dual	Photoelectric

Additional MA Regulations

Additional information on MA smoke detector law can be found at the state website. Some cities and towns have slightly different rules such as requiring photoelectric detectors in all locations. There is also a carbon monoxide law in Massachusetts. Please note that the above is only an overview and should not be considered legal advice. Please contact your local fire department for local regulations and with any questions that you may have about this law.