What Is Radon and Why Homeowners Need to Take It Seriously

Let’s talk about something I wish more homeowners took seriously—radon. It’s invisible, it has no smell, and you can’t taste it. But don’t let that fool you. According to Health Canada, radon is a naturally occurring radioactive gas that can build up inside homes, and long-term exposure is the second leading cause of lung cancer in Canada after smoking. That’s not something homeowners should ignore. So how do you test for radon and reduce radon levels?

My son and I have been talking about the dangers of radon gas for years now. You’ll even see in our show, Holmes and Holmes, that we test all our projects for radon gas – and have taken steps to mitigate it and install radon mitigation systems.

 

How Radon Gets Into Your Home

Radon comes from the natural breakdown of uranium in soil and rock. It seeps up through the ground and can enter your home through:

• Cracks in your foundation
• Gaps around pipes and sump pumps
• Crawl spaces and basement floors
• Poorly sealed slabs

And here’s the kicker—it doesn’t matter how new or old your home is. Health Canada makes it clear: any home can have elevated radon levels.

If your house traps air—especially in the basement—you’re at higher risk. Radon becomes a problem when it builds up indoors and you breathe it in over time. Inside your lungs, it breaks down and releases radiation that damages lung tissue.

Radon Testing for Your Home

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All homes have some levels of radon. Only a test will identify the actual levels. Start by getting a radon test (or a test kit). You can buy a short-term test or a long term radon test. Send your radon test for results to determine your next steps. Test your home. Understand your levels. And if needed, install proper mitigation.

A radon test measures the concentration of radon gas in your home, usually reported in becquerels per cubic metre (Bq/m³). The national guideline is 200 Bq/m³—but the reality is, there is no completely “safe” level of radon exposure over time.

How to test for radon gas

There are two main ways to test for radon:

1. Long-term testing (the gold standard)
This is what Health Canada recommends. You place a small detector in the lowest lived-in level of your home for at least 3 months, typically during the fall or winter when your house is sealed up.

2. Short-term testing
These give quicker results, but they’re less accurate because radon levels fluctuate day to day. They can be a starting point, but not the final answer.

You can:

• Use a DIY radon test kit
• Or hire a certified radon measurement professional

Either way, the key is consistency and proper placement. Put it where people actually spend time—not a storage room you never enter.

What is Radon Mitigation? 

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Radon mitigation is any process or system used to reduce radon concentrations in buildings. A radon mitigation system reduces the indoor radon level as low as reasonably achievable. If levels are high, you bring in a certified radon mitigation professional who understands airflow, pressure differences, and building science. 

If your home tests high for radon, don’t panic—but don’t ignore it either. This is where proper mitigation comes in.

The most effective method is called sub-slab depressurization. In simple terms, a pipe system is installed beneath your foundation that pulls radon gas from under your home and vents it safely outside before it ever gets inside.

Other methods to reduce radon can include:

• Sealing foundation cracks (helpful, but not enough on its own)
• Improving ventilation in basements
• Installing radon extraction systems in crawl spaces

But here’s the truth I’ve learned on job sites: sealing alone doesn’t solve the problem. You need a proper mitigation system.

 

How Do You Reduce Radon In A Home?

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Radon is the #1 cause of lung cancer amongst non-smokers. Some techniques prevent radon from entering your home while others reduce radon levels after it has entered. It is generally recommended to focus on radon mitigation methods that prevent the entry of radon.

The use of sealing alone has not been shown to lower radon levels significantly or consistently. Radon can enter through the soil, windows, floor drains, and more. 

The cost of a radon mitigation system ranges greatly. It can cost anywhere between $500 and upwards of $2,500.

RELATED

7 FREQUENTLY ASKED QUESTIONS ABOUT RADON GAS

Presence of Radon Gas

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Radon is present in every indoor environment so everyone should build with a radon mitigation plan in mind, regardless of where they live. The geological make up of the soil and bedrock certain areas are prone to have higher levels of radon – but any home can have dangerous levels of radon, regardless of geography.

Did You Know?

In Canada Calgary, South Western Ontario, and the Interior of BC are examples of areas where high radon gas levels have been recorded but there are many more. In the USA certain states have recorded high levels, including PA, NH, NC and MN

 

RADON MEASUREMENT: The concentration of radon in the air is measured in units of picocuries per litre (pCi/L) or becquerels per cubic meter (Bq/m3). 

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