Radon gas is often called the “silent killer” of Canadian homes. Invisible, odourless, and tasteless, it seeps up from the ground and can accumulate to dangerous levels indoors—especially in colder climates where homes are tightly sealed for much of the year. But is radon truly a problem in Ottawa, or is the concern overblown? The evidence might shock you.

What is Radon and Why Should You Care?

Radon is a naturally occurring radioactive gas produced by the breakdown of uranium in soil and rock. Outdoors, it disperses harmlessly. Indoors, however, it can accumulate to levels that pose a significant health risk. When inhaled, radon’s radioactive particles can damage lung tissue, increasing the risk of lung cancer over time. In fact, radon is the leading cause of lung cancer in non-smokers and the second leading cause overall in Canada, responsible for more than 3,000 deaths annually—more than car accidents, carbon monoxide, and fire deaths combined.

The Ottawa Situation: Is the Risk Real?

High Radon Potential in Ottawa

Ottawa’s geology makes it particularly susceptible to elevated radon levels. Geological studies confirm that about half the city sits atop formations known for high radon potential, including the Billings Formation, Eastview member of the Lindsay Formation, and parts of the Bobcaygeon Formation. This means that the risk of finding high radon in Ottawa homes is not just theoretical—it’s a documented reality https://www.simonairquality.com/services/radon-testing/.

How Common is Radon in Ottawa Homes?

Recent community testing and scientific studies paint a concerning picture:

• A 2021 community report found that 1 in 5 Ottawa homes tested above Health Canada’s radon guideline of 200 Bq/m³. That’s 18% of homes, nearly triple the national average.
• Another study found radon concentrations in Ottawa homes ranging from as low as 8 Bq/m³ to as high as 1,525 Bq/m³, with an average of 110 Bq/m³.
• Health Canada’s own cross-country survey confirms that about 10% of homes nationally will test above the radon guideline, but local geology can significantly increase this percentage in regions like Ottawa.

No Home Is Immune

What’s truly shocking is the unpredictability of radon. Two similar houses on the same street in Ottawa can have vastly different radon levels due to differences in soil, construction, and ventilation. There are no “radon-free” areas in Ottawa or anywhere in Canada—the only way to know your risk is to test your home.

How Dangerous Are Ottawa’s Radon Levels?

Health Risks at a Glance

• Health Canada’s guideline: 200 Bq/m³ (above this, remediation is strongly recommended).
• World Health Organization’s guideline: 100 Bq/m³ (above this, action is advised).
• Lung cancer risk: For every 100 Bq/m³ increase in long-term radon exposure, the lifetime risk of lung cancer rises by 16%.
• At 200 Bq/m³: Lifetime risk of lung cancer is 17% for smokers and 2% for non-smokers.
• Synergistic risk: Smokers exposed to radon have a dramatically higher risk of lung cancer due to the combined effects.

Ottawa’s Numbers in Context

• 18% of homes above 200 Bq/m³ in Ottawa.
• Some homes have recorded levels over 1,500 Bq/m³—more than seven times the Canadian guideline.
• Even “average” homes can have levels above 100 Bq/m³, which the WHO considers a threshold for concern.

Why Is Ottawa So Vulnerable?

Several factors make Ottawa a radon hotspot:

• Geology: The city sits atop uranium-rich rock formations that produce more radon.
• Climate: Long, cold winters mean homes are sealed tightly, trapping radon indoors for extended periods.
• Building Practices: Modern energy-efficient homes are often more airtight, which can increase radon accumulation if not properly ventilated.
• Basements: Many Ottawa homes have finished basements, which are at higher risk for radon buildup due to their proximity to the ground.

Public Awareness: The Hidden Crisis

Despite the high risk, awareness and action remain low:

• Only 6% of Canadian households have tested for radon.
• In Ottawa-Gatineau, just 12% of residents have tested their homes, and only 3% have taken steps to mitigate high levels.
• Many residents are unaware of radon’s dangers or mistakenly believe their home is safe if it’s new, old, or in a “good” neighbourhood—none of which are reliable indicators.

Real Stories: Ottawa Residents Confront Radon

The numbers come alive in personal stories. One Ottawa homeowner, planning to turn his basement into a playroom, discovered radon levels of 340 Bq/m³—well above Health Canada’s guideline—after receiving a flyer urging him to test. The discovery was even more poignant after learning a family friend had died of lung cancer despite never smoking, only to find high radon levels in their home after the fact.

Reddit threads and community forums are filled with similar accounts: homes in Kanata and Bridlewood testing anywhere from 70 Bq/m³ to over 400 Bq/m³, with mitigation systems bringing levels back down to safer ranges.

Testing: The Only Way to Know

Radon is undetectable without proper testing. Health Canada recommends every home in Ottawa be tested for radon, ideally over at least three months during the heating season for the most accurate results. Test kits are affordable (typically $30–$60, sometimes less through community programs) and widely available.

Key facts about testing:

• Long-term (3+ months) tests are most accurate.
• Place the detector in the lowest lived-in level of your home (often the basement).
• Results are sent to a lab for analysis.
• No area is guaranteed “safe”—testing is essential regardless of location or home age.

What If Your Home Tests High?

Remediation Is Effective

If your home tests above the guideline, don’t panic—radon mitigation is highly effective. The most common solution is sub-slab depressurization, which uses a fan and piping to vent radon from beneath your home to the outdoors. This can reduce radon levels by more than 80%.

Mitigation facts:

• Cost typically ranges from $1,500 to $3,500.
• Professional installation is recommended to ensure effectiveness and compliance with safety standards.
• Increasing ventilation can help, but is usually only effective for modestly elevated levels.

After Remediation: Keep Monitoring

It’s wise to continue monitoring radon levels after remediation to ensure the system is working properly. Some residents use digital detectors for ongoing peace of mind.

Policy, Prevention, and the Path Forward

Why Isn’t More Being Done?

Despite the clear risk, radon is often overlooked in public health discussions. Barriers include:

• Low public awareness.
• Perceived cost or hassle of testing and remediation.
• Lack of mandatory testing in real estate transactions.
• Limited financial support for mitigation.

What Can Be Done?

• Public education: More outreach is needed to inform residents about radon risks and the importance of testing.
• Incentives: Subsidies or tax credits for testing and mitigation could help more homeowners take action.
• Policy change: Requiring radon testing during home sales or rentals would help ensure more homes are safe.
• Professional guidance: Physicians and public health officials can play a key role in raising awareness and encouraging testing.

The Shocking Truth: Ottawa’s Radon Risk Is Real

The evidence is clear: radon is a serious and underappreciated health risk in Ottawa. With nearly 1 in 5 homes testing above Health Canada’s guideline, the city faces a higher-than-average risk compared to many other parts of Canada. The danger is compounded by low public awareness and action, leaving thousands of residents unknowingly exposed to a leading cause of lung cancer.

No home is immune. No neighbourhood is “radon-free.” The only way to protect your family is to test.

Frequently Asked Questions

Is my home at risk if it’s new/old/renovated?

Radon can affect any home, regardless of age, design, or renovations. The only way to know is to test.

Can I fix high radon levels myself?

While increasing ventilation can help lower modestly elevated levels, professional mitigation is recommended for readings above 200 Bq/m³.

How often should I test?

Test every home at least once, ideally during the heating season. Retest after significant renovations or if you install a mitigation system.

What about schools and workplaces?

Radon can accumulate in any building. Testing is recommended for schools, daycares, and workplaces as well.

Conclusion: Take Action—Don’t Wait

Radon is a hidden danger that can have devastating consequences if ignored. Ottawa’s unique geology and climate make the risk higher than many realize. But the solution is simple: test your home, and if needed, fix it.

The answer to “Is radon in Ottawa really a problem?” is a resounding yes. The real shock is how many people are still unaware—or unprotected. Don’t be one of them.