November 12, 2026 –As temperatures drop and Ontarians spend more time inside their homes, air quality becomes even more important. As part of Radon Action Month, Tarion is encouraging Ontario homeowners to learn about radon and your home.
Radon is a naturally occurring odorless, colourless gas that can occur naturally in the ground and can enter a home through foundation cracks, construction joints, floor drains and openings around service pipes. Radon can become a health concern if it is trapped indoors and high levels accumulate over time. For more on radon and health risks, visit Health Canada’s website.
All homes are likely to contain some radon, and levels can vary significantly from one home to another, even between neighbouring properties. The only way to determine the radon level in a home -- and if it could impact your health -- is through testing.
Radon tips for homeowners in both new and older homes:
- Know where radon is most likely to accumulate. Radon levels are often higher in basements and crawlspaces because these areas are in contact with the ground.
- Test your home. Homeowners can use a do-it-yourself radon test kit or hire a certified radon measurement professional. Health Canada recommends long-term testing, and homeowners should ensure testing is conducted using approved devices or professionals certified through the Canadian National Radon Proficiency Program.
- Understand if you should take action. Health Canada has established a guideline of 200 becquerels per cubic metre (Bq/m³). If long-term testing shows levels above this guideline, steps should be taken to reduce radon concentrations within the home.
In a new home? Learn what your warranty covers. For newly built homes in Ontario, radon remediation is covered under the builder's warranty for up to seven years from the home's original date of possession if radon levels exceed Health Canada's guideline.
“At Tarion, we want homeowners to understand both the risks associated with elevated radon levels and the protections available to them under Ontario's new home warranty program,” says Peter Balasubramanian, CEO of Tarion. “If testing identifies a problem, new home owners should contact their builder to give them the opportunity to address the issue. Tarion can also help homeowners understand their warranty coverage and available options.”