This is not a future compliance requirement. It is already the law. Beginning January 1, 2026, all homeowners, landlords, and residential building managers in Ontario are required to meet updated Carbon Monoxide alarm installation requirements under the Ontario Fire Code, aimed at strengthening public safety.

If you own a home in Markham, rent a property to tenants, or manage a condominium unit, you need to read this and act — because non-compliance carries real penalties and, more importantly, real danger. Michael John Lau and Neeraj Moolchandani, top real estate agents in Markham Ontario, ensure every buyer and seller client understands this requirement because CO alarm compliance affects listing inspections, home insurance coverage, and the legal obligations of every Ontario landlord.

What Changed on January 1, 2026

Under the updated Ontario Fire Code (Ontario Regulation 87/25, amending O. Reg. 213/07), carbon monoxide alarms are now required on every storey of a home — including basements and floors without bedrooms. Previously, CO alarms were only required near sleeping areas. That sleeping-area requirement did not disappear — it was expanded.

As of 2026, every residential unit in Ontario must have carbon monoxide alarms, regardless of building type or mechanical systems. This has major implications for condo management and multi-residential properties — even if your unit is entirely electric with no gas appliances, the building may have gas systems in shared mechanical rooms that create CO risk.

Your Specific Obligation as a Markham Homeowner

Walk your home today. Count the floors — basement, main floor, upper floors. You need a working CO alarm on each one. Test it using the test button before treating it as operational. Test monthly, replace batteries at least once a year (unless you have a 10-year sealed battery model). For Markham homes with natural gas furnaces, gas water heaters, gas fireplaces, or attached garages — which describes the overwhelming majority of Markham’s detached housing stock — the requirement is unambiguous.

Combination smoke-and-CO alarms satisfy both requirements simultaneously and are available at Canadian Tire, Home Depot, and most hardware stores across Markham for $25 to $60 per unit.

Your Specific Obligation as a Markham Landlord

The installation and ongoing maintenance obligation is yours as the landlord — not the tenant’s. If a tenant reports a non-working CO alarm, you must respond promptly and replace it. Failure to maintain compliant CO alarms is a breach of your obligations under the Ontario Fire Code and the Residential Tenancies Act simultaneously.

For Markham landlords with secondary suites — basement apartments — both the main unit and the secondary suite require compliant CO alarms on every floor. A secondary suite with one CO alarm adjacent to the sleeping area but none on the basement floor itself does not meet the 2026 requirements. Both units, all floors.

The Insurance and Legal Implications

Most insurance contracts require you to maintain your home according to local safety laws. An insurance claim related to CO exposure in a home where the Fire Code’s requirements are not met creates genuine coverage risk — the insurer may deny a claim on the basis that the homeowner was not in compliance with applicable safety legislation. In a rental unit context, the landlord’s personal liability exposure for CO-related injury to a tenant in a non-compliant property is significant. Failure to comply can result in fines ranging from several hundred dollars to more severe penalties for repeated violations.

CO Alarm Compliance and Markham Real Estate Transactions

For buyers, CO alarm compliance is a standard item to verify during the home inspection condition period. For sellers, compliance is a prerequisite to a clean inspection report. Michael John Lau and Neeraj Moolchandani, top real estate agents in Markham Ontario, make CO alarm compliance part of every pre-listing preparation checklist — because a $40 alarm installation before listing prevents a post-inspection negotiation issue that is entirely avoidable.