ImmoMulti — a direct buyer of income properties on the North Shore — meets plex owners every week who underestimate exactly how far their obligations around smoke and carbon monoxide alarms reach. Yet this is one of the few areas where a simple oversight can be extremely costly: a denied insurance payout, a civil lawsuit, even penal liability after a fire. The basic rule is clear — installation is the landlord's job, routine upkeep is the tenant's — but the nuances (10-year sealed batteries, CO alarms, regulated placement) make all the difference. Here is what every plex owner should verify, sourced directly from Québec authorities.
Who installs and who maintains the alarms in a plex?
The obligation to install and provide smoke alarms falls on the landlord (owner). Routine maintenance — testing the device and replacing the battery when it is weak — falls to the tenant (occupant), except for sealed, non-replaceable batteries. The landlord remains bound to replace a defective or end-of-life alarm.
Responsibility is shared, but it is not symmetrical. As a plex owner, it is up to you to ensure every unit has compliant smoke alarms installed in the right places. The Régie du bâtiment du Québec sets this out in its rental safety advice: the landlord provides and installs the alarms, while the tenant keeps them in working order.
In practice, the tenant must test the alarm (ideally monthly), report any defect, and — for models with a removable battery — replace the battery when it is weak or dead. On your side, you must hand over functional devices at the start of the lease, react quickly to any report, and replace the alarm itself if it is damaged, painted, or past its useful life.
Source: Régie du bâtiment du Québec — Rental safety tips.
What is the 10-year sealed-battery smoke alarm rule?
Over the past few years, several Québec municipalities have tightened their requirements by mandating smoke alarms with a long-life sealed lithium battery, non-removable, lasting about 10 years. The goal is to eliminate the classic silent alarm: the battery removed or never replaced.
In Montréal, by-law RCG 12-003 (amended in 2020) requires this type of alarm in all residential buildings built before 1985 that are not already equipped with electric (hardwired) alarms. More recent buildings are subject to distinct requirements based on their year of construction. As the Association des propriétaires du Québec summarizes:
"All residential buildings built before 1985 and not equipped with an electric-type smoke alarm" must now have a smoke alarm with a sealed 10-year lithium battery.
— Association des propriétaires du Québec (APQ), on the Montréal agglomeration by-lawThe key takeaway for owners: a sealed-battery alarm cannot be recharged or repaired. Once it reaches the end of its 10 years (indicated by the manufacturing or replacement date on the casing), it must be replaced in full. That is a plannable expense — not a surprise.
What sets a compliant alarm apart
- It carries the ULC logo (Underwriters' Laboratories of Canada), confirming compliance with Canadian standards;
- Its manufacturing or replacement date is visible on the casing;
- It has not exceeded its 10-year lifespan;
- It is installed in the required location and has not been painted or obstructed.
Sources: APQ — Change to smoke alarm regulation on the Island of Montréal; Société d'habitation du Québec — Smoke alarms.
Is a carbon monoxide alarm mandatory in a plex?
Yes. Since April 1, 2019, a carbon monoxide alarm is mandatory in a dwelling if it contains a combustion appliance, or if a wall, floor or ceiling is adjacent to a space housing a combustion appliance or a parking garage. In a plex, the landlord is responsible for providing and installing these alarms.
Carbon monoxide (CO) is an odourless, colourless, and deadly gas. That is why the Government of Québec made a CO alarm mandatory since April 1, 2019 in the dwellings concerned. The rule covers units equipped with a combustion appliance — wood stove, gas fireplace, gas water heater, oil furnace, generator, etc. — but also those where a wall, floor or ceiling is adjacent to a space housing such an appliance or to a parking garage.
For a multi-unit owner, this last point is crucial. A plex with an integrated garage, a shared laundry room housing a gas water heater, or a central boiler room can trigger the obligation to install CO alarms in several units — not only in the one containing the appliance. The alarm must comply with standard CAN/CSA-6.19.
Source: Government of Québec — Carbon monoxide alarms.
Where should you install the alarms in your plex?
Placement is not just a matter of common sense — it is regulated. For the carbon monoxide alarm, the Government of Québec specifies it must be installed on each floor where there is a bedroom and near the bedrooms. Importantly, it must never be placed inside a garage. It is also recommended to keep it at least 2 metres from cooking and combustion appliances to avoid false alarms.
| Alarm type | Where to install | Who is responsible |
|---|---|---|
| Smoke | On each floor, including the basement; near bedrooms. Follow the municipal by-law. | Install: landlord · Test / battery: tenant |
| Carbon monoxide (CO) | On each floor with a bedroom; near bedrooms; never inside a garage. | Install: landlord · Upkeep: tenant |
| Replacing the device | As soon as it is defective, damaged, painted, or after 10 years. | Landlord |
For smoke alarms, the general rule is at least one per floor — including the basement — and near the bedrooms. Because the precise requirements (number, location, battery type) vary from one municipality to another, a plex owner on the North Shore — in Terrebonne, Blainville, Boisbriand or Saint-Eustache — should always confirm their city's fire-safety by-law.
What are the consequences after a fire or claim?
A missing, badly installed, or non-functional alarm can expose the landlord to a refused or reduced insurance payout, civil liability lawsuits from occupants and, in the event of death or injury, penal liability. Documented compliance protects the owner.
This is where the stakes become financial and legal. After a fire or a CO intoxication, the first question asked will be: were the alarms present and functional? Three types of consequences await the negligent owner:
- Insurance: most income-property policies require the owner to maintain compliant safety equipment. A breach can be invoked by the insurer to reduce or refuse the payout following a claim.
- Civil liability: an injured tenant — or a victim's relatives — can sue the landlord for fault, alleging the absence of functional alarms.
- Penal liability and fines: municipal fire-safety by-laws provide for fines for missing or non-compliant alarms; a death or serious injury can lead to heavier penal consequences.
The "it was the tenant's job to change the battery" trap
Even though routine upkeep falls to the tenant, the landlord cannot shed the obligation to install and provide compliant alarms, nor the duty to act on a report. In a dispute, it is the landlord who will have to demonstrate their diligence.
For specific situations — the exact terms of your policy, a contested split of responsibility — consult an insurance broker and, if needed, a lawyer or notary.
Documenting compliance: an asset when you sell
The good news: compliance is cheap and easy to document. Keep a log for each unit of your plex: installation and replacement dates of the alarms, models and standards (ULC, CAN/CSA-6.19), written instructions handed to tenants, and checks performed between tenancies. Keep this file with your other maintenance records.
This log is not only protection against your insurer: it is also a selling point. A multi-unit buyer — or their inspector — will appreciate a building whose fire safety is in order and documented. Conversely, missing or expired alarms found at the pre-purchase inspection can become a point of downward negotiation.
In short, smoke and CO alarms are an area where compliance is simple, inexpensive, and heavy with consequences if neglected. Check your municipality's by-law, install compliant devices, replace them on time, and document everything. Your income property — and your peace of mind — will be better for it.
Informational content only. Fire-safety rules and effective dates are subject to change by the Régie du bâtiment du Québec, the Québec government, and municipalities. Consult a professional for advice specific to your building and municipality.
