Nicole's Law Explained: Massachusetts CO Detector Requirements

Last verified: August 24, 2026

Nicole's Law is what Massachusetts calls M.G.L. chapter 148 section 26F 1/2, its carbon monoxide detector statute. The statute is named for Nicole Garofalo, a 7-year-old who died in Plymouth in 2005 after snow blocked the exhaust vent on her family's heating system and pushed carbon monoxide back into the home. Governor Mitt Romney signed the bill that fall and the alarm-installation provisions took effect March 31, 2006, making Massachusetts one of the first states to mandate CO alarms across covered residential occupancies regardless of building age or owner-occupied status. The framework includes owner and landlord operational duties, pre-transfer inspection workflow through local fire departments, and device standards tied to approved alarm pathways.

Massachusetts also has explicit anti-tampering language in section 27A, which can carry meaningful penalties when devices are intentionally disabled or removed. Because compliance combines statutory requirements with fire-code implementation details, owners should keep section-linked records for installation, testing, and correction before occupancy or transfer milestones.

For portfolio operators, the safest strategy is jurisdiction-specific execution with statewide statute citations in every compliance file. Keeping fire-department inspection records attached to transfer and lease files strengthens defensibility.

Key Takeaways

CO detector requirements for Massachusetts
Applies to homes?	Yes
Applies to rentals?	Yes
Applies to hotels/STRs?	Yes
Applies to schools?	Yes, under a condition
Applies to workplaces?	No

Schools and workplaces

Schools: it depends, and the test is one you can apply to the building itself. Massachusetts deleted the occupancy list rather than the classroom, so the conditions alone decide, and it has kept that amendment across an edition change. Section 915.1.1 as adopted reads only "Carbon monoxide detection shall be provided where any of the conditions in Sections 915.1.2 through 915.1.6 exist", where the model limits itself to Group I-1, I-2, I-4 and R occupancies and Group E classrooms. The base moved from the 2015 International Building Code to the 2021 with the Tenth Edition of 780 CMR, which the Board of Building Regulations and Standards made "first effective on October 11, 2024 with a concurrency period, during which either the ninth or tenth edition building codes could be utilized". That period, extended once, ended on 30 June 2025, "at which time the tenth edition will be the only building code in effect". So a permit filed on or before 30 June 2025 could still have been taken out under the 2015-based Ninth Edition, and one filed after that date could not. The amendment reads word for word the same in both editions, so a project permitted on either side of either date meets the same test. That amendment is wider than the model rather than narrower, and it removes the occupancy argument entirely: a classroom is covered where it contains a fuel-burning appliance or fireplace, is served by a fuel-burning forced-air furnace, sits in a building holding such equipment with a communicating opening, or adjoins an attached private garage. Massachusetts leaves the classroom placement rule alone and then writes a way out of one condition, which is a shape worth reading in that order. Section 915.2 as Massachusetts prints it sends the reader to "Sections 915.2.1 through 915.2.4, or 915.2.5", so the model 915.2.3 stands: detectors in classrooms in Group E occupancies, with their alarm signals "automatically transmitted to an on-site location that is staffed by school personnel", excepting a Group E occupancy with an occupant load of 30 or less. The two Massachusetts additions at 915.2.4 and 915.2.5 cover newly installed fuel-fired equipment and alternative technical routes. The way out sits at 915.1.3, the forced-air-furnace condition, and it names classrooms expressly. Detection "shall not be required in dwelling units, sleeping units and classrooms if a carbon monoxide detector is provided in the first room or area served by each main duct leaving the furnace, the carbon monoxide alarm signals are automatically transmitted to an approved location, and notification is provided in accordance with 915.6". So a Massachusetts school on ducted fuel-fired heat can move the detectors to the duct outlets instead of the classrooms, and the price of doing it is automatic transmission either way. Transmission is the one thing neither route lets a district avoid. For a school already standing, Section 915.1 bridges to 527 CMR 1.00 section 13.7, whose 13.7.6 asks for alarms within ten feet of any bedroom door on every level, a rule written around dwellings that a school building will rarely engage.

Workplaces: Massachusetts places no carbon monoxide detection duty on an office, shop or other workplace. Federal and state occupational rules set an exposure limit for carbon monoxide in air; they do not require a detector to be installed, and this row is about installation. Deleting the occupancy list from Section 915.1.1 did not widen the SPACES the section reaches, and that distinction decides this. Sections 915.1.2 through 915.1.6 are written as duties in "dwelling units, sleeping units and classrooms", and Massachusetts left those sections alone, so an office, shop or factory is named in none of them however the occupancy gate reads. Nicole's Law, M.G.L. c. 148 section 26F1/2, is the other instrument and it reaches "every building occupied in whole or in part for residential purposes", which a workplace is not.

When Are CO Alarms Required?

Buildings with fuel-burning appliances
Buildings with attached garages
Home sales or property transfers
Residential occupancy pathways in section 26F 1/2 include covered conditions tied to combustion and enclosed parking risk.

Where to Install CO Alarms

On each level of a dwelling unit, including finished basements and cellars, under 527 CMR 1.00 c 13.7.6. Crawl spaces and uninhabitable attics are the two exceptions, and unlike most states that carry that phrasing Massachusetts wrote it into its own carbon monoxide rule rather than borrowing it from a smoke alarm section.
No more than ten feet from each bedroom door, measured in any direction, under 527 CMR 1.00 c 13.7.6.5(3). The alarm goes outside the bedroom; this does not displace the separate requirement for smoke alarms inside it.
In a bedroom or its attached bathroom where fuel-burning equipment is installed in that room, under the property maintenance code, and on a story with a bedroom the alarm sits outside the bedroom at a minimum under 780 CMR 5313.4.3.
Alarms must sound at a minimum of 85 dBA at ten feet under 780 CMR 5313.4.4, and a combination smoke and carbon monoxide device must carry a voice identification announcing which hazard it has detected.

For detailed placement guidance beyond legal requirements, see where to place carbon monoxide detectors.

Device Requirements

Approved and operational carbon monoxide alarms in conformance with Massachusetts statutory and fire-code requirements.
Combination smoke and CO devices are permitted when listing standards are satisfied.

Landlord and Tenant Responsibilities

Landlord: Landlords must provide and maintain required alarms for covered rental occupancy at tenancy start and ongoing operation. Provision: 26F 1/2.

Tenant: Occupants may not tamper with required alarm devices and should report deficiencies. Provision: 26F 1/2.

Local fire department procedures drive practical inspection and sign-off timing in transfer and occupancy workflows.

Full Massachusetts landlord and tenant carbon monoxide duties, with citations

Enforcement

Enforced by: Local fire departments enforce inspection and compliance workflow under Massachusetts statutory framework.

Enforcement typically occurs:

At sale or transfer inspection checkpoints where compliance documentation is required.
During enforcement response to missing, disabled, or noncompliant devices.

What a Tenant Can Do in Massachusetts

When a carbon monoxide alarm stops working in a rented home in Massachusetts, these are the five routes a tenant can take and where each one comes from.

"Via general law" means the Massachusetts carbon monoxide statute itself is silent and the remedy comes from the state's landlord-tenant law instead. The remedy is available even though the alarm rule does not contain it.

"No provision found" is a finding rather than a gap in the research: the chapter that would carry that remedy was read and contains nothing either way. What was read is named beside the row.

Tenant remedies for a defective carbon monoxide alarm in Massachusetts, with the citation or the body of law searched for each.
Rent withholding	Via general lawM.G.L. c.239 8A. Framed as a defence and counterclaim in a possession case: the tenant claims the difference between the agreed rent and the fair value of the use and occupation. The owner must have known of the conditions before the tenant fell into arrears, and a written board of health inspection notice creates a presumption that the owner knew from the date it was received. The court may require the tenant to pay the fair value into court, and there is no recovery of possession where the counterclaim equals or exceeds what the landlord is owed, or where the tenant pays the balance within one week of the court's notice.
Repair and deduct	Via general lawM.G.L. c.111 127L. Capped at four months' rent in any twelve-month period or period of occupancy, whichever is shorter, computed on the highest monthly rent in that window. The gate is a certified violation of the standards of fitness for human habitation plus written notice to the owner, so this is not a remedy a tenant can start alone.
Right to end the lease	No provision foundSearched: M.G.L. chapter 186 (landlord and tenant), chapter 239 section 8A, chapter 111 sections 127A to 127L, and the State Sanitary Code at 105 CMR 410. No provision lets a tenant end the tenancy over an uncorrected code violation. The route is constructive eviction, which is common law, requires the condition to be serious enough to force the tenant out, and requires the tenant to leave, so it ends the tenancy by abandonment rather than by a statutory right exercised on notice.
Notice the tenant must give	Via general lawM.G.L. c.111 127L; M.G.L. c.239 8A. No statutory waiting period attaches to anything the tenant sends, because the tenant's notice is not what starts the repair-and-deduct clocks. Those run from the code agency's written notice to the owner. A tenant's own written notice still matters for the 8A defence, where it goes to proving the owner knew, and an inspection notice does the same job by presumption.
Landlord cure period	Via general law, 14 daysM.G.L. c.111 127L. Two clocks inside one section, both running from the written notice: five days to begin the repairs or contract for them, fourteen days to substantially complete them. A shorter period can be ordered, which is the opening for a live CO hazard. The fourteen days is recorded here because it is the point at which the tenant's own remedy becomes available.

Applies to every row above:Nicole's Law and the State Sanitary Code put the alarm duty on the owner and neither creates a tenant remedy, so all five columns come from general law. Massachusetts then differs from every other state in the fifty-one in one structural way: its strongest remedy is gated on an official certification rather than on the tenant's own letter. Missouri asks for a municipal certification too, but only where the landlord disputes the repair in writing. Here it is the default. The repair-and-deduct clocks in c.111 127L run from a board of health or code enforcement certification and written notice to the owner, which means the practical first step for a Massachusetts tenant is to call the board of health, not to write to the landlord. The trade for that extra step is the highest ceiling any capping state puts on a single repair, four months' rent, against California's one and Illinois's $500. Two things a reader should have beside that: five states cap nothing at all, and Hawaii allows more across a year, three months' rent every six months against the four months Massachusetts allows every twelve.

Remedies last checked 2026-08-03. Compare Massachusetts with the other states.

What Massachusetts Requires in Lodging

The Massachusetts carbon monoxide requirement reaches hotels and short-term rentals.

Hotels already standing: covered too. The Massachusetts requirement reaches an existing hotel and not only one being built.

Operator duty: Two instruments and the building code decides which one applies. For an existing hotel the route is M.G.L. c. 148 section 26F1/2 and 527 CMR 1.00 section 13.7, which the state building code itself points at: Massachusetts amends Section 915.1 of the building code to read that carbon monoxide detection "shall be installed in existing buildings in accordance with 527 CMR 1.00: 13.7". For new construction and for work that brings the building code into play, Section 915 governs, and Massachusetts has amended 915.1.1 to drop the model's occupancy list altogether: detection is required "where any of the conditions in Sections 915.1.2 through 915.1.6 exist", with no Group I or R qualifier to argue about. Section 915.2.2 then puts the detection inside the guest room unless neither the room nor its attached bathroom holds a fuel-burning appliance and no forced-air furnace serves it.

Full Massachusetts hotel and short-term rental requirements

Penalties for Non-Compliance

M.G.L. chapter 148 section 27A prohibits disabling or removing required detection devices and provides penalty exposure that can include fines and imprisonment.

M.G.L. c.148 section 27A.

Additional Notes

Massachusetts compliance execution should combine statute sections with local fire department process.
Operators should confirm municipality-specific inspection scheduling before transfer deadlines.

Local Rules That Differ From State Law

At least one Massachusetts municipality sets CO requirements that go beyond the statewide rule. Where your property sits decides which applies, and the stricter one governs.

Boston

Boston attaches a carbon monoxide duty to the start of every tenancy, which is a trigger Nicole's Law does not use. Subsection 9-1.4 sets the standards a rental unit must meet on the day it is handed to a new tenant, and paragraph (B)(4) requires the property owner to provide and maintain functioning carbon monoxide detectors to the standard of 527 CMR 31 at that moment. The state statute makes the alarm a permanent condition of the building and checks it when the building is sold; Boston makes it a condition of the handover and gives the tenant a way to test it. Under paragraph (C), a new tenant who asks within 24 hours of moving in gets an Inspectional Services inspection within two business days, and anything found is cited under both this subsection and the State Sanitary Code. Read the definitions before relying on it: NEW TENANT covers a letting of more than 30 days, so a short stay falls outside the whole subsection, and a separate duty in Subsection 9-1.3 makes the owner request a full inspection within 45 days of turnover. Boston also prices the state inspection rather than leaving it to the fire department: Subsection 18-1.19(O) fixes the fee for a smoke and carbon monoxide inspection ordered under M.G.L. chapter 148 sections 26F and 26F1/2 at $50 for a single-family dwelling or a single unit, $100 for a two-family, $150 for a building of six units or fewer and $500 above that, with a reinspection charged at the same rates.

Boston Municipal Code Subsection 9-1.4(B)(4) and (C), Rental Dwelling Unit Delivery Standards, with the inspection fee schedule at Subsection 18-1.19(O) Checked 2026-08-10.

Gloucester

Gloucester will not let a short-term rental operate without a working carbon monoxide alarm, and it says so in the permit rather than in a building code. Section 5-66 requires every operator to hold an annual short-term rental permit from the inspector of buildings, and subsection (s) makes the operator certify two things to get one: compliance with state and local health, sanitary, fire and building codes, and functioning smoke and carbon monoxide detectors. The teeth are in Section 5-67, where a violation costs $400 and each day counts separately, and in Section 5-66(m), where three violations in six months bar the unit from short-term letting for six months. The article took effect on 1 January 2025, so anything written about Gloucester lettings before then predates it. This is the same shape as Tuscaloosa in Alabama: the city has no power to rewrite the building code, so it puts the alarm in the licence instead.

Gloucester Code of Ordinances Section 5-66(s)(2), with penalties at Section 5-67, Ord. No. 2024-135 effective 1 January 2025 Checked 2026-08-10.

Holyoke

Holyoke has its own carbon monoxide ordinance and one line of it points the opposite way from the state rule. Section 42-17 covers any residential building heated by fossil fuel equipment inside the structure, requires the seller to submit to a fire department inspection on sale or transfer, and reaches new single-family and multiple-family buildings, rehabilitated ones, and a named list that includes lodging houses, boarding houses, dormitories, fraternity houses, hotels, motels and group residences. The unusual part is placement. The state rule, 527 CMR 1.00 section 13.7.6, works in maximums: an alarm on every level, and on a level with bedrooms no more than ten feet outside any bedroom door. Holyoke adds a minimum, requiring the alarm outside the sleeping area and at least 15 feet from the heating unit, which in a small home with the boiler near the bedrooms leaves a narrow band that satisfies both. The fire chief may require extra units on top. Devices must meet at least UL 2034 as revised on 1 October 1995.

Holyoke Code of Ordinances Section 42-17, Carbon monoxide detectors, Chapter 42 Fire Prevention and Protection Checked 2026-08-10.

What was checked:The earlier entry here said that Massachusetts settles this question outside municipal codes and that reading a city's own code could not answer it. That was half right and it cost this survey four months. M.G.L. chapter 143 section 98 does route a stricter local building standard through the state board, so a Massachusetts city cannot write its own construction rule, and that part stands. What it does not do is stop a city legislating about carbon monoxide by some other power. Boston used its housing-standards power, Gloucester attached a condition to a licence and Holyoke wrote a fire-prevention ordinance. All three are below. The section 98 regulations themselves remain unsearched and could still hold a fourth. Fifteen city codes were read on 2026-08-10: Boston, Cambridge, Somerville, Gloucester, Holyoke, New Bedford, Salem, Brockton, Chelsea, Lawrence, Medford, Peabody, Westfield, Newburyport and Winthrop. Twelve carry nothing, each one control-tested against terms the same index does return. Three limits are worth stating plainly. Malden could not be read at all: its code has a publisher record but no published edition behind it, so its zero is a fact about the publisher. Worcester, Springfield, Provincetown and Nantucket sit on no host reachable from here, and Provincetown and Nantucket are the two places in the state where the short-term rental question bites hardest. And Boston came close to producing a false clean sheet: the publisher that carries fourteen of these cities lists Boston too, but the only thing it holds for Boston is the zoning code, which returns zero for "alarm" and zero for "sprinkler" as well as zero for carbon monoxide. The Boston ordinance below came from a different publisher entirely. One bounded attempt at the section 98 route was made on 2026-08-20 and it did not close the question. The mechanism reproduces cleanly: chapter 143 section 98 lets a town's selectmen or a city's mayor recommend more restrictive standards, which the state board may adopt after finding that special local conditions make them reasonably necessary and that they conform to accepted national practice. What did not surface is any instance of a city having used it for carbon monoxide. That is what the paragraph above predicts: a standard adopted this way lives as a state regulation naming a city, so it is invisible to a search of the city's own code and it is not indexed under the city's name anywhere a general search reaches. Closing it needs the CMR itself or the board's adoption records read directly, not another search. Massachusetts stays unknown above Nicole's Law until somebody does that.

Local sweep last reviewed 2026-08-10.

Official Sources & References

Board of Building Regulations and Standards, Tenth Edition of the Massachusetts State Building Code, 780 CMR , Effective date, base I-Codes and the ninth-edition concurrency period (state code, accessed 2026-08-24)
Massachusetts changed edition over eight and a half months rather than overnight, and this is the page where the Board says so. Read on 2026-08-24 through r.jina.ai; mass.gov answers HTTP 403 to a direct fetch. The Tenth Edition "became first effective on October 11, 2024 with a concurrency period, during which either the ninth or tenth edition building codes could be utilized", and that period "ends June 30, 2025, at which time the tenth edition will be the only building code in effect". It relies on modified versions of the 2021 IBC, IRC, IEBC, IECC, IMC, ISPSC and IFC. The concurrency window matters to anyone dating a permit, because the Ninth Edition and its 2015 base stayed available for eight and a half months after the Tenth Edition took effect.
Massachusetts State Building Code, 780 CMR, Section 915 Carbon Monoxide Detection , 915.1 with its pointer to 527 CMR 1.00 13.7; 915.1.1 as amended; 915.2.1 dwelling units and 915.2.2 sleeping units (building code, accessed 2026-08-09)
Massachusetts amends Section 915.1 so that "carbon monoxide detection shall be installed in existing buildings in accordance with 527 CMR 1.00: 13.7", which is the bridge between the building code and the fire code the record already cites. It also amends 915.1.1 by deleting the model's occupancy list: the text reads only "Carbon monoxide detection shall be provided where any of the conditions in Sections 915.1.2 through 915.1.6 exist", where the model limits itself to Group I-1, I-2, I-4 and R occupancies and Group E classrooms. 915.2.2 requires detection inside sleeping units, with the outside-the-sleeping-area placement available only where the room and its attached bathroom hold no fuel-burning appliance and no forced-air furnace serves them. Read from the Massachusetts jurisdiction view on 2026-08-09; malegislature.gov refused connections and mass.gov answered HTTP 403.
Massachusetts General Laws chapter 148 section 26F 1/2 , 26F 1/2 (state code, accessed 2026-02-16)
Primary statutory framework for Massachusetts carbon monoxide alarm requirements and transfer compliance.
Massachusetts General Laws chapter 148 section 27A , 27A (state code, accessed 2026-02-16)
Anti-tampering and penalty language relevant to required detection devices.
Massachusetts General Laws chapter 148 section 26F 1/2 (inspection and transfer context) , Sale and transfer compliance portions (state code, accessed 2026-02-16)
Supports transaction-stage compliance and inspection workflow details.
Massachusetts law about carbon monoxide detectors (official state guidance) , Statute and fire-code reference summary (agency guidance, accessed 2026-02-17)
Official guidance index that consolidates statute and implementation references.
Boston Fire Department, Fire Prevention Division, Carbon Monoxide Detectors, reprinting 527 CMR 1.00 c 13.7.6 and Massachusetts State Building Code 780 CMR 5313.4 , 527 CMR 1.00 c 13.7.6, location and device types; 780 CMR 5313.4.3 required locations, 5313.4.4 alarm intensity, 5313.4.5 maintenance (fire code, accessed 2026-08-20)
Read verbatim on 2026-08-20 for two things the page previously took from an encyclopedia. It gives the effective date as 31 March 2006, which settles the disagreement between the summary and the old source note, and it reproduces the placement rule the page had been gesturing at without citing: the alarm "shall be located in each level of a dwelling unit including finished basements and cellars but not including crawl spaces and uninhabitable attics", with 780 CMR 5313.4.3 repeating the exclusion in parentheses, an alarm no more than ten feet outside any bedroom door, and 85 dBA at ten feet.
Town of Provincetown, Massachusetts, Nicole's Law , Origin of the statute and what it requires (agency guidance, accessed 2026-08-20)
An official Massachusetts municipal government page carrying the origin facts the summary states: "7-year-old Nicole Garofalo, who died in January 2005 when a heating vent in her house was blocked by snow drifts, allowing carbon monoxide to accumulate in the home", and that Massachusetts passed the law in 2005 reaching residences with any carbon monoxide source. It replaces a general-encyclopedia citation that carried the same facts at one remove and gave the effective date as April 2006, which is wrong.

Disclaimer: This page explains the law as it stood on August 24, 2026. It is general information, not legal advice, and reading it creates no attorney-client relationship. Requirements vary by city, county and building type, and statutes and codes are amended: confirm the current text with the issuing authority before acting on it. Each requirement here cites the instrument it comes from, so you can check it at source.

Frequently Asked Questions

For Massachusetts audits, which statutory reference establishes CO alarm authority?

Two instruments, and reading only the famous one gives a Massachusetts owner half the rule. M.G.L. chapter 148 section 26F 1/2, Nicole's Law, creates the duty. Where the alarm actually goes is written in the fire code, 527 CMR 1.00 section 13.7, and it is stricter than most states in two ways at once. Section 13.7.6 asks for an alarm on each level of a dwelling unit including finished basements and cellars, excepting only crawl spaces and uninhabitable attics, and separately for one no more than ten feet from each bedroom door measured in any direction. Section 27A is the third piece and it is about tampering rather than installation.

Are Massachusetts rentals and owner-occupied homes both covered?

Both, and Massachusetts does not distinguish between them the way most states do. The duty in M.G.L. chapter 148 section 26F 1/2 attaches to the dwelling, not to the tenancy, so an owner-occupier and a landlord owe the same thing and the placement rule in 527 CMR 1.00 section 13.7.6 is the same for each. What differs is when somebody comes to look. A rental is inspected when a local programme requires it; an owner-occupied home is inspected at sale or transfer, which for many households is the only time the rule is ever enforced against them.

What happens at sale or transfer in Massachusetts?

The local fire department inspects and issues a certificate, and no closing proceeds without it. That is what makes Massachusetts different from the states where a carbon monoxide rule exists on paper and is never enforced against a private house, because sale is the enforcement point, and it arrives for every property eventually. The thing that catches sellers is the placement standard rather than the presence of an alarm, because 527 CMR 1.00 section 13.7.6 wants one on every level including a finished basement and one within ten feet of each bedroom door, and a house with a single alarm in the hallway passes neither.

What penalties apply for disabling required alarms in Massachusetts?

M.G.L. chapter 148 section 27A is stranger and stricter than a tampering rule, and reading it is worth two minutes. "No person shall shut off, disconnect, obstruct, remove or destroy, or cause or permit to be shut off, disconnected, obstructed, removed or destroyed, any part of any sprinkler system, water main, hydrant or other device used for fire protection or carbon monoxide detection and alarm in any building owned, leased or occupied by such person or under his control or supervision, without first procuring a written permit so to do from the head of the fire department." Two things follow. It binds an occupant as well as an owner, because the building need only be occupied by that person, so a tenant who takes the battery out is inside it. And the lawful route out is a written permit from the fire chief rather than a judgment call, with one exception the section makes itself, for temporary disconnection to make necessary repairs or to prevent freezing or other property damage.

How do Massachusetts requirements compare with Rhode Island workflows?

The placement standard is where they part company. Massachusetts writes its own in 527 CMR 1.00 section 13.7.6, an alarm on every level including finished basements and one within ten feet of each bedroom door, and enforces it through a fire department certificate at sale. An owner who moves a portfolio across the border cannot carry the Massachusetts installation plan with them and expect it to be right. For the neighbouring position, see Rhode Island CO detector laws.

Practical CO Detector Guides

Beyond legal requirements, these guides help you choose, install, and maintain CO alarms:

Where to place carbon monoxide detectors, room-by-room placement recommendations
CO detector beeping patterns, what different alarms mean
What to do if your detector goes off, emergency response checklist
CO resources and links, official agencies and safety information