Smoke and Carbon Monoxide Detector Inspections

*ATTENTION* Please be advised that due to Governor Baker's emergency declaration made on March 20, 2020, and due to the current coronavirus (COVID-19) pandemic, all smoke detector and carbon monoxide inspections may be deferred for up to ninety (90) days after the State of Emergency has been lifted. Governor Baker's order states that due to the state of emergency, the BUYER, and not the seller is responsible for the completion of this legally required inspection. RESIDENTIAL BUYERS MUST APPLY FOR INSPECTION THROUGH THE FIRE DEPARTMENT PERMITTING SITE. Please contact the Fire Prevention Office for further information. 


Did you know that...

Some facts about smoke and carbon monoxide detectors
  • When fire strikes, you may have less than one minute to safely get out of the building?
  • 3,000 people die each year in fires in the United States?
  • Carbon monoxide (CO) is poisonous, odorless, colorless, and tasteless and can be fatal if inhaled?
  • Smoke alarms and carbon monoxide detectors are required in every residential buiilding in Massachusetts?
  • In order to sell your home in Massachusetts, you are required to obtain a smoke detector/carbon monoxide detector certificate from your local fire department?
  • Smoke detector and carbon monoxide detector inspections can be applied for on our quick and easy to use online permitting website!

Click here for the CFD online permitting system!

Inspection Information

  • An inspection for smoke detectors and carbon monoxide detectors are generally required to sell your home.
  • Inspections can ONLY be scheduled online.
  • We perform inspections for the sale of a home on Tuesday and Thursday between 1PM and 3PM only. We are not able to guarantee a time during this slot, so a responsible adult (18+) needs to be on site for the inspection to take place.
  • The cost of inspection is based on the number of units to be inspected -Single family or unit $50, Two Family or units $100, three to six units $150, and seven units and greater $500.
  • Please refer to the chart below for information regarding placement of smoke detectors. Detectors must generally be placed on a ceiling although there are some exceptions to this. Call the Fire Prevention Office at (978) 251-4288 if you have questions.
  • Please request all inspections at least 24-48 hours in advance. Inspection Fees must be paid before the inspection will be scheduled. Inspection requests received within 24 hours of the requested inspection will be considered on a case-by-case basis.
Massachusetts Guidelines for Smoke and Carbon Monoxide Alarm Requirements
Year built or substantially modified (per building permit issue date)

Before 1975

1975 -  8/27/1997

8/27/1997 - 9/1/2008

9/1/2008 - 2/1/2011

2/1/2011 - Present

Smoke Alarm Power SupplyBattery or HardwiredHardwired, InterconnectedHardwired, Interconnected w/ battery backupHardwired, interconnected w/ battery backupHardwired, interconnected w/battery backup
Type of Smoke Alarm Technology (Photoelectric or Ionization)
On the same level, if a required detector is located more than 20 feet from a kitchen or full bathroom doorway, it shall be:Photoelectric with a sealed 10-year nonrechargeable, nonreplaceable batteryPhotoelectric OR Ionization

Photoelectric OR IonizationPhotoelectric OR Dual Detector*Photoelectric ONLY

On the same level, if a required detector is located less than 20 feet from a  kitchen or full bathroom doorway, it shall be:Photoelectric with a sealed 10-year nonrechargeable, nonreplaceable batteryPhotoelectric OR Ionization

Photoelectric ONLYPhotoelectric ONLYPhotoelectric ONLY
Smoke Alarm Placement
On every habitable level & including the basement level on the CEILING; at the base of each stairway leading to an occupied floor aboveSmokeSmokeSmokeSmokeSmoke
On CEILING outside each sleeping area in hallwaySmokeSmokeSmokeSmokeSmoke
Inside every bedroomNot RequiredNot RequiredSmokeSmokeSmoke
Finished attic (habitable)SmokeSmokeSmokeSmokeSmoke
Garage (Attached)Not RequiredNot RequiredNot RequiredHeat DetectorHeat Detector
Carbon Monoxide (CO) Alarm Power Supply and Placement
Battery, or plug in with battery backupAllowedAllowedAllowedNot AllowedNot Allowed
Hardwired, interconnected w/ battery backupAllowedAllowedAllowedRequiredRequired
ALARM PLACEMENT - A CO alarm shall be located on each habitable level, including finished portions of basements and attics. A CO alarm shall be placed in the hallway outside each separate sleeping area (where bedrooms are located, NO FARTHER THAN 10 FEET FROM ANY BEDROOM DOOR.

All detectors must be less than 10 years old. One smoke alarm is necessary for every 1,200 square feet of area or portion thereof, per floor.


*Dual detectors are a single smoke detector that uses both photoelectric and ionization technology.

Smoke and Carbon Monoxide Detector Information

Chelmsford Fire Prevention Office

Chelmsford Fire Prevention
50 Billerica Road
Chelmsford, MA 01824

Town Hall Room LLO5
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