Of all the paperwork on a Massachusetts closing checklist, the smoke and CO certificate is one of the items that most often trips up sellers. It's not complicated, but it is specific, and the rules change depending on the age of your house. A failed inspection a week before closing means a scramble to find an electrician and a second appointment with a busy fire department.

As a broker and a Massachusetts real estate instructor, I cover this topic with licensees. Here's the plain-English version for homeowners in Danvers, Marblehead, Gloucester, Swampscott, Ipswich, and the rest of the North Shore.

What the Law Requires

Two state laws drive the inspection. M.G.L. Chapter 148, Section 26F requires the seller to equip a home with approved smoke detectors upon sale or transfer, and Section 26F½ (Nicole's Law) adds the carbon monoxide requirement. The head of the local fire department enforces both.

A few points sellers often miss:

• The seller is responsible. The statute puts the obligation on the seller.
• Newer homes aren't automatically exempt. The state's consumer guide notes that many purchase agreements and mortgage lenders require the certificate even for homes permitted after 1975.
• "Transfer" is broad. A February 2017 State Fire Marshal memo explains that a change of ownership can trigger the CO inspection even without a sale price, such as a gifted deed or a transfer into a trust.
• One visit covers both. Fire departments typically inspect smoke and CO alarms at the same appointment.

Which Alarms Your Home Needs

The requirements follow the building code in effect when the home was built or last substantially renovated. Plenty of North Shore homes, from antique colonials to mid-century capes, predate 1975, so start by confirming which category yours falls into.

Homes built before January 1, 1975

• Smoke alarms on every habitable level and in the basement, on the ceiling at the base of each stairway, and outside each sleeping area.
• Alarms must be photoelectric (photoelectric/ionization combination units are allowed more than 20 feet from a kitchen or bathroom).
• New or replacement alarms must be photoelectric with a hush feature, and battery-powered units must use a sealed, non-replaceable 10-year battery.
• Two-family homes also need alarms in shared common areas.

Homes built or renovated after 1975

• 1975 to August 27, 1997: hardwired, interconnected alarms on each level, at the base of stairs, and outside sleeping areas, plus one per 1,200 sq. ft. of living space per level.
• After August 27, 1997: adds an alarm inside every bedroom, with battery backup; alarms within 20 feet of a kitchen or a bathroom with a tub or shower must be photoelectric.
• On or after January 1, 2008: a heat alarm is required in an attached garage.
• On or after February 4, 2011: all smoke alarms must be photoelectric.

Carbon monoxide alarms (all homes)

If your home has fossil-fuel-burning equipment (an oil or gas furnace, gas water heater, gas range or dryer, or a fireplace) or an attached enclosed garage, you need CO alarms on every level, including habitable basements and attics, within 10 feet of each bedroom door. Combination smoke/CO units are allowed in many cases.

The 10-Year Rule That Fails Inspections

Massachusetts requires smoke alarms to be replaced once they are more than 10 years old or past the manufacturer's life limit. The manufacture date is printed on the back of each unit, and an alarm with no date is treated as more than 10 years old. Inspectors commonly remove alarms from the ceiling to check the type and date, so a unit that still beeps on test day can still fail.

Before you schedule, pull each alarm down and look at the label. It's a ten-minute job that can save you a re-inspection.

Cost and Timing

• Fees: Each town sets its own, but M.G.L. c.148 §10A caps the inspection fee at $50 for a single-family, $100 for a two-family, and $150 for buildings with six or fewer units. No extra charge applies for CO when both are inspected together.
• Shelf life: The state certificate form (FP-007C, rev. 6/23) says the certificate expires 60 days after issuance.
• Scheduling: Call your fire department once you have a signed purchase and sale agreement and a firm closing date. Have the year built and any major renovation dates ready. Your REALTOR will typically do this for you.
• Paperwork: The state application form requires an original signature; photocopies aren't accepted, though most towns now send versions.

Some departments only inspect on certain days. Wakefield's fire department, for example, lists Wednesday inspection hours. Ask your local department how far out they're booking.

A Pre-Inspection Checklist for Sellers

• Confirm your home's build year and any major renovation dates.
• Check every alarm's manufacture date and replace anything over 10 years old.
• Make sure replacements are the right type (photoelectric, hush feature, sealed 10-year battery where applicable).
• Test every smoke and CO alarm the day before.
• Make sure your street number is visible from the street, which state law (M.G.L. c.148 §59) requires.
• If your home has hardwired alarms that need replacing, book a licensed electrician early.

Daylight saving time ends Sunday, November 1, 2026. The clock change is a good reminder to test your alarms, whether you're selling this season or next spring.

If you're weighing a sale, my North Shore seller's guide walks through the full process, and you can request a free home value estimate to see where your home stands. Real estate professionals can take continuing education on topics like this through Armstrong Field Real Estate School .

This article is general information, not legal advice. Requirements can vary with a home's construction and renovation history; your local fire department makes the final determination.

Frequently Asked Questions

Do I need a smoke detector certificate to sell a house in Massachusetts?

Yes. Under M.G.L. c.148 §26F and §26F½, a residential home must have approved smoke and carbon monoxide alarms when it is sold or transferred, and the local fire department issues a Certificate of Compliance after a successful inspection. Lenders and purchase agreements also commonly require it at closing.

How much does a smoke and CO inspection cost in Massachusetts?

Each city or town sets its own fee, but state law (M.G.L. c.148 §10A) caps it at $50 for a single-family home, $100 for a two-family, and $150 for a building with six or fewer units. When the smoke and CO inspections are done at the same visit, there is no extra charge for the CO portion.

How long is a Massachusetts smoke certificate good for?

The state Certificate of Compliance form (FP-007C) states that the certificate expires 60 days after it is issued by the head of the fire department, so time the inspection with your expected closing date.

What type of smoke detectors are required when selling a home in Massachusetts?

It depends on when the home was built or last substantially renovated. For homes built before 1975, alarms must be photoelectric, and any new or replacement battery-powered alarm must have a hush feature and a sealed, non-replaceable 10-year battery. Newer homes generally require hardwired, interconnected alarms that meet the building code in effect when they were permitted.

Will an old smoke detector fail the inspection?

It can. Massachusetts requires smoke alarms to be replaced once they are more than 10 years old or past the manufacturer's life limit. The manufacture date is printed on the back of the unit, and an alarm with no date is treated as more than 10 years old.