REALTORS® and Radon: Protecting Buyers and Sellers

Oct 17, 2023

Posted by
British Columbia Real Estate Association


Radon, a naturally occurring odourless and colourless radioactive gas, may be out of sight but it certainly shouldn’t be out of mind when it comes to real estate transactions. In fact, radon is present at different concentrations (depending on the makeup of bedrock or sediment) throughout Canada. If radon levels in a home surpass a certain threshold, the associated health risks, particularly the heightened potential for lung cancer, increase proportionally. The risk escalates with higher concentrations, and there is no minimum level below which the risk is considered negligible. Health Canada has established a Radon Guideline of 200 Bq/m3, which is the benchmark that would likely be recognized by a court. As a result, radon levels at or exceeding this guideline are recognized as a significant latent defect.

Understanding radon risks is more than just a professional responsibility under the British Columbia Financial Services Authority Radon Precaution Guidelines. It’s an opportunity to give clients peace of mind as they make the biggest financial decision of their lives.

How radon enters a home

Radon typically seeps through the ground and into buildings through cracks in the foundation and/or floor slabs. According to the Canadian Real Estate Association’s Homeowners Guide to Radon, radon can also enter through other openings, like unfinished dirt floors, window casements or gaps around service pipes. Factors like bedrock and soil types, soil moisture level, and seasonal temperature fluctuations also influence indoor radon levels.

Radon and lung cancer

Scientists estimate that radon exposure accounts for an estimated 16 percent of lung cancer deaths in Canada. A report from the Canadian Association of Radon Scientists and Technologists (CARST) explains why:

When inhaled, radon gas particles remain in lung tissue and begin to decay. As the radon particles decay, they release bursts of radiation that can damage the lung tissue cells. Over time, the cell damage can lead to the development of lung cancer.

What is considered a "high level" of radon? While Health Canada advises Canadians to pursue a radon level "as low as reasonably achievable," 200 becquerels per cubic metre is considered the maximum allowable. There is no lowest threshold, as the risk of lung cancer increases with radon concentration. For that reason, the World Health Organization suggests homeowners take action if concentrations are over 100 becquerels.

For more information on radon, visit the BC Centre for Disease Control Radon page, Interior Health's radon guide, or Health Canada's radon page.

Testing and mitigation

The good news about radon is that testing and mitigation are relatively affordable and easy. Anyone can test their home for radon. All it takes is a radon testing device that can be found at stores like Home Hardware, Walmart or Home Depot or ordered online from the BC Lung Foundation’s page.

While radon mitigation is also relatively straightforward, it’s best to hire a radon mitigation specialist certified by the Canadian – National Radon Proficiency Program (C-NRPP) to take on the job, which average $3,000 depending on the size and style of the home. Fixes can involve improving ventilation, sealing cracks in foundation walls and floors, or installing a depressurization system to draw radon away from the basement. The Canadian Lung Association offers grant support for radon mitigation, you can find all the details and how to qualify for it here.

The BC Building Code is currently undergoing significant revisions, and these changes are anticipated to take effect in 2024. Following a public consultation last spring, the proposed revisions include a notable shift in policy. Under the new regulations, there will be mandatory requirements to incorporate a passive radon system, with additional technical specifications for homes all across the province. For more information on these proposed changes, you can refer to the Public Review document here.

Your responsibilities as a REALTOR®

Above all, don’t forget that if a property has been tested for radon and shown to have levels on or above 200 becquerels per cubic metre, this is a material latent defect. If you’re representing a client selling such a property, this information must be disclosed in the Property Disclosure Statement. But there’s more to upholding professional standards than just disclosure when it comes to radon. Here’s how you can help:

  • First, educate yourself about radon. There are many good sources such as Health Canada and Take Action on Radon. BCFSA provides guidance to help discuss the importance of radon with clients: Radon Checklist for Sellers’ Agents, for Buyers’ Agents, and for Rental Property Managers.
  • BCREA has created a FAQ document on Radon with the support of Dr. Noah Quastel from the BC Lung Foundation. The document addresses common questions and provides external resources on the topic here.
  • Enroll in the updated BCREA Radon for REALTORS® Course, to deepen your understanding of radon and how it relates to the real estate transaction. If you sign up between November 1 - 30, 2023 you'll automatically enter the giveaway of one of five radon testing kits! Winners will be announced on December 7, 2023.
  • Educating yourself about radon also means understanding the radon levels in the region where you do business. The BC Radon Map is an interactive map that compiles readings from homes across BC. 
  • Follow BC Lung Foundation's radon related projects.
  • Ask sellers if they have had radon testing done. If they have, ask for a copy of the test results. If test results fall below 100 becquerels per cubic metre, this is an added selling feature.
  • If it is 200 becquerels or higher and remediation hasn’t been done, be sure your client understands your duty to disclose this as a material latent defect.
  • If your seller has already done remediation using a C-NRPP certified professional, ask for confirmation that the work has been done and that the radon levels are now in safe zones. Completed remediation is another selling point to highlight.
  • In cases where remediation hasn’t been done, you can add value to your client by connecting them with a C-NRPP certified professional to get the work done.
  • When representing a buyer, consider including a radon holdback (retention) clause in the contract. This involves the buyer and seller agreeing to set aside a sum of money from the purchase price that is likely to be enough to cover the cost of a typical radon remediation system. The money is held by a third party (for example, a solicitor) until the test result is known and any reduction measures have been done. If the test shows low radon levels and that no further action is necessary, the bond money is released to the seller. If the test shows that high radon levels are present and that remediation is necessary, the work is paid for from the bond money; any excess is released to the seller.
  • If your buyer is planning on doing major renovations after buying, make sure they understand that this could impact radon levels in the home, even if it has been remediated in the past.

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