Smoke alarms and carbon monoxide detectors are among the most important safety requirements for Ontario rental properties. They are also among the most frequently cited violations found during property inspections. For Ontario landlords, compliance is not optional — it is legally mandated under the Fire Code, and violations can result in substantial fines and, more importantly, life-threatening risk to your tenants.

Smoke Alarm Requirements Under Ontario's Fire Code

Ontario's Fire Code (O. Reg. 213/07) requires working smoke alarms in all residential occupancies. For rental properties, the specific requirements include:

• A smoke alarm on every storey of a dwelling unit
• A smoke alarm outside every sleeping area (bedroom or area where people sleep)
• In new construction (post-2006), smoke alarms must be interconnected — when one goes off, all go off — and hardwired with battery backup
• In older buildings, battery-operated smoke alarms are acceptable if they meet ULC (Underwriters' Laboratories of Canada) standards
• Smoke alarms must be tested regularly and batteries replaced as needed

Landlords are responsible for ensuring smoke alarms are installed, functional, and maintained at the start of each tenancy. Tenants are responsible for not tampering with or removing smoke alarms. If a tenant removes or disables a smoke alarm, the landlord must repair or replace it upon learning of the situation.

Carbon Monoxide Alarm Requirements

Ontario has some of the strongest CO alarm requirements in North America. CO detectors are required in:

• All residential units that contain a fuel-burning appliance (gas furnace, gas stove, gas fireplace, oil furnace)
• All residential units that have an attached garage
• All residential units adjacent to a room containing a fuel-burning appliance

The CO alarm must be installed adjacent to each sleeping area in the unit. As of 2014, CO detectors were made mandatory province-wide for these premises — this is not a new regulation, but it remains one of the most commonly found violations. CO is odourless and colourless — it is called the "silent killer" because occupants receive no sensory warning without a functioning detector.

Combination Smoke/CO Alarms

For most residential rental units, combination smoke/CO alarm units are the most practical compliance solution. They satisfy both requirements with a single device, reduce the number of units to test and maintain, and are available at a wide range of price points. Ensure any combined unit bears the ULC certification mark and is designed for the location where it will be installed (some locations require a sealed unit or specific installation height).

Inspection and Maintenance Responsibilities

Landlords must ensure all alarms are tested at the start of each tenancy and at least annually during the tenancy. Best practice is to test during move-in inspections, move-out inspections, and annual property inspections. Document the testing in your inspection report — include the date, the unit, and whether the alarm tested functional.

Smoke alarm units typically have a service life of 8–10 years. The manufacturing date is printed on the back of most units. Alarms that are past their service life should be replaced regardless of whether they appear to be functioning. CO alarms typically have a service life of 5–7 years.

Fines and Legal Liability

Violations of Ontario's smoke alarm and CO detector requirements can result in significant fines. Under the Fire Protection and Prevention Act, individuals can face fines up to $50,000 and corporations up to $100,000. Municipal fire inspectors can issue orders requiring immediate compliance. Beyond regulatory fines, non-compliance creates serious civil liability exposure if a fire or CO incident occurs and a properly functioning detector was absent.

Frequently Asked Questions

Can a tenant remove a smoke alarm?

No. It is an offence under Ontario's Fire Code to remove or tamper with a required smoke alarm. Tenants who do so can face their own fines, and landlords must repair or replace any removed or disabled alarm upon notification.

What if my building has a central fire alarm system?

Multi-unit buildings with central fire alarm systems must still comply with Ontario's Building Code and Fire Code requirements for individual suite smoke alarms. The central system does not replace the requirement for suite-level smoke alarms in most circumstances. Consult your local fire department or fire inspector for specifics on your building type.

Do I need CO detectors in every suite of an apartment building?

Yes, if the suite contains a fuel-burning appliance or is adjacent to a room containing one (such as a boiler room). Suites in all-electric buildings without attached garages may not require CO alarms. Confirm with your local fire department.