Massachusetts Carbon Monoxide Detector Law

The Law in Plain English

Required in all residential buildings with fossil-fuel equipment or attached garages.

What This Means for Homeowners & Renters

Massachusetts requires carbon monoxide detectors in all residential dwellings, a mandate in effect since 2006. Required in all residential buildings with fossil-fuel equipment or attached garages. This law applies to homeowners and renters alike. Landlords are required to install and maintain CO detectors in rental units. Compliance is straightforward: install at least one UL-listed CO detector on each floor of your home, with emphasis on areas near sleeping rooms. Replace the unit every 5–7 years as the electrochemical sensor degrades over time regardless of visible function.

Landlord Requirements in Massachusetts

Landlords are required to install and maintain CO detectors in rental units.

If you are a renter and your landlord has not provided a working CO detector, you have the right to request one in writing. Document the request and keep a copy. In most states with a landlord mandate, failure to provide a detector is a code violation that can be reported to local housing authorities.

Recommended CO Detector Placement

Regardless of what Massachusetts law requires, safety experts recommend placing CO detectors on every level of your home, within 10 feet of each sleeping area, and near any fuel-burning appliance (furnace, water heater, gas stove, fireplace). Replace your CO detector every 5–7 years — electrochemical sensors degrade over time regardless of whether the device appears functional.