Smoke and carbon monoxide alarms in Ontario homes: the rules, including the 2026 CO changes

Renovations that add bedrooms, finish basements or install gas appliances change where alarms are required. Ontario's rules are enforceable, with fines, and they changed for carbon monoxide alarms on January 1, 2026.

Smoke alarms

Every home in Ontario must have a working smoke alarm on every storey and outside all sleeping areas, including cottages and seasonal homes. The homeowner is responsible for installing and maintaining them; failing to comply can lead to a $360 ticket or fines of up to $50,000 for individuals and $100,000 for corporations.

Carbon monoxide alarms from January 1, 2026

The Fire Code changes that took effect on January 1, 2026 require a CO alarm adjacent to each sleeping area and on every storey of the home, including storeys without bedrooms. They apply to existing homes that have a fuel-burning appliance, a fireplace or an attached garage.

Who is responsible

In owner-occupied homes the homeowner is responsible; in rental homes, the landlord. Multi-unit buildings have their own information sheet from the Office of the Fire Marshal.

Placement

Install alarms on ceilings, or high on a wall if a ceiling is not possible, away from bathrooms, windows and cooking appliances. Choose battery-backed units, since hard-wired alarms without backup do not work during power outages.

Plan it into the renovation

A new basement bedroom, a gas fireplace or a furnace replacement changes the requirement. Building permits may require interconnected alarms in new work; ask your building department and your local fire department.

Prevention Checklist

• Smoke alarm on every storey and outside sleeping areas.
• CO alarm next to each sleeping area and on every storey if you have fuel-burning appliances, a fireplace or an attached garage.
• Use battery-backed alarms.
• Landlords: install and maintain alarms in rental units.
• Re-check alarms whenever a renovation adds bedrooms or appliances.

References

1. Government of Ontario. Fire safety at home, Web page, Smoke alarm rule; fines. Accessed 2026-11-01.
2. Government of Ontario. Carbon Monoxide Alarm Rules, Existing Homes (OFM information sheet, December 2025), Web page, 2026 CO requirements; responsibility. Accessed 2026-11-01.
3. Government of Ontario. Carbon monoxide safety, Web page, Placement; battery backup. Accessed 2026-11-01.

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