Smoke/CO Detector Inspection

The Marlborough Fire Department wants to assist all homeowners in making the inspection for compliance a simple step in the transfer or sale of property. The following information describes the proper placement of smoke detector, proper marking/numbering of a property, how to apply for an inspection, and the fee for issuing a certificate of compliance. Applications must be made using the following link: 

Basic Smoke Detector Placement

The State Law requires an operating smoke detector on every habitable level, including the basement. Finished attic spaces also need smoke detector coverage. In homes with floor space exceeding 1,200 square feet per floor, a second detector will be required.

  • First Floor: Smoke detectors should be placed on the ceiling in the hallway near a stairwell to the second floor, unless there is a bedroom on the first floor. In this case, a smoke detector should also be placed outside the bedroom door. Placing the detector more than 6 feet from a kitchen or bathroom door will help to avoid alarms set-off by cooking or steam.
  • Second Floor: The smoke detector must be placed on the ceiling in the hallway common to all bedrooms, normally at the head of stairs. The idea is for the smoke to get to the detector before it reaches the bedrooms. Again avoid placement within 6 feet of a bathroom door.
  • Basement: Smoke detectors should be placed on the cellar ceiling at the base of the cellar stairs. If the ceiling is unfinished, place the detector on the edge of the joist (not in the bay between two ceiling/floor joists). Never place the detector at the top of the basement stairs by the cellar door.

General Information: Smoke detectors should be placed on the ceiling a minimum of twelve (12) inches from the nearest wall. Placement of smoke detectors on a wall is not adequate and will result in failure of compliance. Exception: Mobile Homes, HUD Provisions.

Testing Before Inspection: You may already have smoke detectors in your home. If the detector is installed according to regulations, push the test button on each detector to make sure it works. A fresh battery should be placed in each detector and marked with a date. Hardwired A/C detectors in newer properties should already be installed properly and only need to be tested for proper operation. Testing of one A/C powered smoke detector should activate all the other detectors in hardwired A/C powered smoke detector installations.

Note: Properties that were built after 1975 shall have a primary powered (electric) system installed per the Massachusetts Building Code at the time of construction. Battery operated detection may not be substituted for primary interconnected hard wire systems.

Click Here for the guide to installation requirements according to the age of your home.

Inspection Appointments

To schedule an appointment, beginning on Monday March 27, 2023 all permitting will be done on the City of Marlborough Open Gov / ViewPoint platform. By clicking on the following link: and selecting the Fire Department tab residents and agents will be able to apply for an inspection. 
Detectors must be in the proper place and operational. Any property that fails due to lack of detectors, detectors not functioning, improper placement, or lack of a house number will incur an additional $50.00 fee.

The inspector will issue a "Certificate of Compliance" after the inspection. The certificate is valid for 60 days from the date of inspection. You are urged not to wait until the last minute before closing on a property to receive an inspection. As the end of each month approaches, the inspection times rapidly fill up each day and an appointment may not be available.

Required House Numbers

All homes must be properly marked as part of the smoke detector certificate of compliance. Such numbers shall be no less than four (4) inches in height, of a contrasting color to the dwelling, and located so as to be readily visible from the road.

Despite the pleasant appearance of brass numbers, they are very difficult see on light colored homes and are not recommended.

Click Here for a guide on house numbers


Smoke detectors are one of the most important safety features of your home. Properly installed, working smoke detectors will give you the early warning you need to safely escape from a fire. But how do you make sure your detectors are working? One important way is to replace them after 10 years.

As electronic devices, detectors are subject to random failures. Product, installation, and maintenance standards are used to assure products work as designed despite this. Part of the technical basis for the first detector product standard was an assessment of expected failure rate, estimated at four per million hours of operation or one every 30 years. Early field studies of detector reliability, notably by Canada's Ontario Housing Corporation, confirmed the essential accuracy of this estimate, restated as a 3% failure rate per year. This means a very small fraction of home smoke detectors will fail almost immediately, and 3% will fail by the end of the first year. After 30 years, nearly all the detectors will have failed, most years earlier.

State & Local Laws

"All buildings or structures occupied in whole or in part for residential purposes upon the sale or transfer, shall be equipped by the seller with approved smoke detectors." (MGL Chap.148 Sec. 26F)

"All residential structures with a fuel or wood burning appliance or adjacent garage must install (per manufacturer instructions) an approved CO detector (battery operated, plug-in with battery backup, hardwire with battery back-up, combination types*), 1 per habitable floor at a minimum, installed so every bedroom has a detector within 10' of its door. *Must also comply with smoke detector rules — 20' from a bathroom or kitchen if not photoelectric type." (MGL Chap. 148 Sec. 26F1/2)

"Every building in the City shall have affixed a number representing the address of such building. Said number shall be of a nature and size and situated on the building so that it is visible from the nearest street or road providing vehicular access to such building." (Code of the City of Marlborough, Chap. 137, Sec. 137.6)