What Happens After a High Radon Test Result

Posted in Radon Testing, on November 07, 2025

Receiving negative test results is scary, no matter if it's your health or your home — and with more homes in Toronto testing positive for high levels of radon gas, many homeowners across the city are asking: what next? SafeAir helps families with indoor air quality problems by offering safe and reliable radon testing and air quality testing in Toronto. We’ve helped thousands of people identify air quality pollution indoors and helped them make changes to safeguard and improve their health. Here’s what we’ll help you with if your home has tested positive for high levels of radon gas. 

Understanding Your Radon Test Results

The first thing you should know is that radon is natural — most homes will test positive for some level of radon gas, but Health Canada has determined that readings above 200 Bq/m³ are not safe. If your results come back above this level, Health Canada advises you to take prompt action to lower your exposure.

Assessing The Risk to Your Home and Family

Radon gas is a toxic, radioactive gas that has profound long-term implications for human health. Prolonged high exposure to radon gas is a known carcinogen and is the leading cause of lung cancer in Canadians after cigarette smoking. 

Next Steps After a High Radon Result

What happens next after a >200 Bq/m³ reading? At SafeAir, we usually ask several key questions. 

• If we didn’t do your radon test, we’ll want to know if you had a short-term or long-term test? Short-term testing can be affected by weather or seasonal shifts, so we generally recommend long-term testing for greater accuracy. We may recommend follow-up testing to compare results. 
• Where is the radon coming in? Radon floats through the soil underneath our homes — it’s formed very deep in the earth’s crust. It gets into our homes through cracks in the foundation, around windows or doors, and through sump pumps.
• What is the ventilation like in your home? Radon gas tends to collect in basements or similar spaces with reduced ventilation. Improving ventilation is often the easiest and most dramatic way to lower your radon testing results.

Radon Mitigation Options

SafeAir will help you develop a mitigation plan that takes into account the answers to these questions and others. Some of the easiest fixes for radon gas are looking for and filling cracks and gaps that allow radon in. Locating and filling these entry points can often dramatically lower your readings.

Depending on your results, you may need a different strategy, like sub-slab depressurization, where a mechanical device helps to divert radon. Every home needs a unique solution, and similar properties on the same block may have wildly different test results — which is why SafeAir tailors mitigation solutions to each home. 

Retesting and Long-Term Monitoring 

After your radon mitigation, we usually recommend follow-up testing. This ensures that the solutions you’ve chosen have worked and that your risk is lowered or eliminated. Preventing radon gas in the long term may take annual or long-term monitoring or maintenance, such as sealing new foundation cracks, which is where follow-up testing can be so valuable.

If you have high radon testing results, don’t panic! SafeAir is ready with safe, science-based remediation planning and mitigation strategies. We can help you identify radon gas during standard air quality testing in Toronto or as a stand-alone test. Call or email our team to learn more about our radon testing protocols or book your test today. 

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