Understanding Radon Gas and Its Impact on Real Estate

I’ve been in the real estate industry for almost 40 years now and I’ve been aware of what Radon Gas is and some of its potential health issues for quite some time. Most of my information about Radon came from US sources and I knew testing for Radon in the US was more prevalent. MY thoughts were that it wasn’t a big deal here in Canada and in particular Guelph. Our governments and industry regulators have not communicated a lot about Radon. Since our governments tend to be more proactive and risk adverse than the Americans I didn’t spend a whole lot of time on the subject.

Turns out I might have been misguided on that assumption.

This starts with an email from a physicist and PHD candidate working for a local laboratory Lex Scientific. I’ve used Lex many times over the years to test for things like UFFI and Asbestos when doing due diligence for some of our clients. It led to a meeting and a review of what the issues are and me taking a deep dive into the subject.

What Is Radon Gas?

Radon is a naturally occurring radioactive gas released from the gradual breakdown of uranium found in soil, rocks, and water. Since it’s odorless and invisible, it can seep into homes, particularly through foundation cracks, gaps, or poorly sealed basements, without detection. Once indoors, radon builds up over time, posing health risks to anyone exposed.

Radon in Ontario

While radon is prevalent worldwide, its impact varies based on geographic and geological factors. Ontario is among the regions where radon levels can run high, particularly in areas with uranium-rich soil such as Windsor-Essex County, Leeds, Grenville and Lanark District, and Chatham-Kent.

Eye-Opening Statistics

Over 25% of Ontario homes have radon levels above the World Health Organization (WHO) action level of 100 becquerels per cubic meter (Bq/m³).
Approximately 8% exceed Health Canada’s guideline of 200 Bq/m³, where remediation is strongly recommended.

With radon levels differing from one home to the next, even neighboring properties can have stark variations. That’s why testing is important for understanding your home’s specific situation.

Why Should Homeowners Care?

The Health Risks

Radon isn’t just another environmental concern—it’s a proven public health risk. Prolonged exposure significantly increases the likelihood of developing lung cancer. Alarmingly, radon ranks as the second leading cause of lung cancer in Canada, right behind smoking, and the leading cause among non-smokers.

Health Impacts in Numbers

Radon exposure contributes to about 850 deaths annually in Ontario due to lung cancer.
Smokers exposed to elevated radon levels face exponentially higher cancer risks compared to non-smokers.

Reducing radon in your home can literally save lives. Protecting yourself and your family starts with knowing—and managing—the risks.

Real Estate Implications

Radon isn’t just a health concern—it can potentially impact your home’s value and marketability during a transaction.

Testing and Disclosure: Buyers are becoming increasingly aware of radon issues. Homeowners who perform upfront testing (and mitigation if needed) not only demonstrate responsibility but can avoid price negotiations during the sale.
Buyer Confidence: A test-confirmed safe radon level can reassure buyers, while unresolved high levels can hinder deals.
Cost-Effective Solutions: While some buyers balk at the idea of remediation, addressing radon is typically an affordable improvement that protects both health and property value. Simple fixes like ventilation adjustments or sealing cracks can yield long-term benefits.

How to Address Radon

Managing radon in your home is a straightforward process. Whether you’re a homeowner or looking to buy, here are actionable steps to alleviate concerns around radon gas.

Step 1: Testing

Radon testing is the best way to determine if your home has elevated levels of the gas. Kits are available at many hardware stores for a minimal cost, be sure to check where the results are submitted to and tested by. Or, you can hire professionals to conduct the tests.

Long-Term Testing (90+ days): Offers the most accurate results, especially as radon levels fluctuate with weather and seasonal changes.
When to Test: If you’re considering buying a home, you can test during the conditional period if you are doing an inspection. It’s a different test and not always as accurate but will give you some indication if you have a potential issue or not. For existing homeowners, start testing if it has never been done before or every two years, particularly after home renovations or changes to ventilation systems.

Step 2: Mitigation

If levels exceed Health Canada’s 200 Bq/m³ guideline (or even the WHO’s more conservative threshold of 100 Bq/m³), action is necessary.

Proven Mitigation Methods

Sub-Slab Depressurization: This leading solution involves installing a ventilation system that pulls radon from below the home and vents it safely outside.
Sealing Cracks and Gaps: Often part of the remediation process, this step minimizes radon entry points into the home.
Enhanced Ventilation: Improving air exchange can dilute indoor radon levels, providing another layer of protection.

Step 3: Professional Assistance

Radon mitigation isn’t DIY territory—your home and health deserve expert care. Certified mitigation specialists are trained to design custom solutions that effectively address a home’s unique radon challenges.

Step 4: Ongoing Monitoring

Even after testing and mitigation, radon levels should be monitored regularly. Experts recommend re-testing every two years and immediately following renovations to ensure corrective measures remain effective.

Why It Matters for Guelph Homeowners

Canadians and Guelph residents in particular enjoy a high quality of life and focus on safe, sustainable living. Testing for radon and investing in mitigation is simply the next step in ensuring your home meets that standard. It’s a proactive way to safeguard your health and uphold your property’s market appeal—especially as real estate evolves toward more health-conscious buyers.

Taking Action Today

If testing for radon isn’t already on your radar, consider this your heads up. This is something we’ll be taking to the next level with our Realtors at Keller Williams Home Group Realty.

A simple home test could uncover an invisible hazard and lead to meaningful improvements for your household’s safety and well-being. Worst case scenario is you’re out $50 for a test kit and you get peace of mind that you don’t have any issues.

For prospective buyers, don’t shy away from the radon conversation during home negotiations. A seller’s disclosure—or lack thereof—can guide your choice. Similarly, tested homes with a clean bill of health should leave you with confidence rather than hesitation.

Addressing radon is less about fear and more about awareness and action. Protect your family, safeguard your investments, and ensure your home remains a haven instead of a hidden hazard.

How will you approach radon? The first step is as easy as picking up a kit this weekend.

PS: Canada Day is Tuesday! I’ve got to say that this year I’m feeling a lot more patriotic than I normally would. It might have something to do with the current state of affairs with our largest trading partner, or it could just be I need a reason to fire up the grill and pop a fresh local craft beer.

Enjoy the weekend,

Paul

Appointment Calendar: https://calendly.com/homegrouprealty

Want to search for opportunities in your area?

Search for Homes Here

LISTING OF THE WEEK

307 Auden Road, Guelph ON

$755,000

Detached 2 Storey
3 Bedrooms
1 Full, 1 Half Bath
1,177 Above Grade Sqft

Welcome to this charming 2-storey home, ideally located near multiple elementary schools and a high school, perfect for families.

Step inside and you'll find a warm, functional layout with a bright kitchen that's been thoughtfully refreshed with sleek new quartz countertops (2023) and modern stainless steel appliances, including a new fridge (2023) & dishwasher (2021). The finished basement offers additional living space, perfect for a rec room, home office, or play area. Outside, enjoy the added privacy of backing onto green space with no direct rear neighbours. You'll also find a convenient laundry closest with newer washer & dryer (2023). This is a move-in ready home in a convenient, family-focused neighbourhood. Come see it for yourself!

Listing courtesy of Keller Williams Home Group Realty Brokerage

Learn more