Information about Radon Testing

November is Radon Action Month in Canada.

With approximately 11% of homes in Windsor-Essex County having radon levels above the Canadian Action Limit of 200 Becquerel’s per cubic metre, it’s important for homeowners to test their homes to determine the level of radon gas. Long-term radon exposure is the second leading cause of lung cancer after smoking.

This webpage provides answers to many common questions about radon and how to test for it. For any additional questions, please call the Environmental Health department at 519-258-2146, ext. 4475.

What do I need to know about testing my home for radon?

It’s best to test your home during the Fall and Winter months. Radon levels tend to build up in the home when the doors and windows are closed and sealed during cold weather months. Performing the test during this time will give you a reading of the highest average level of radon that you or your family may be exposed to.

There are 2 common ways to test your home for radon; by using a long-term test kit or a short-term test kit.

A long-term test can be done by purchasing a small, single-use device that collects radon for at least 91 days and costs approximately $50. It must be mailed to a laboratory for results.  Please visit the Take Action on Radon page to order a long-term test kit online or by phone. Visit our radon test kit instruction page for more information on setting up this kind of test device.

A simple to use,  short-term digital testing device can be borrowed for up to 3 weeks at any currently open Essex County Public Library branch. Follow the instructions provided in the kit to operate the device. We recommend collecting data for 1-3 weeks. The longer the testing period, the more accurate your result. The advantages of a short-term device are that you can see your results instantly without sending the device to a lab, and the test device can be re-used. The disadvantage of a short-term testing device is that you will only have a “snap shot” of the radon levels in your home during the brief testing period. It is well known that radon levels can be much higher or lower on different days and at different times of the year. Before making any decisions about fixing your home, it is strongly recommended to follow up with a long-term test kit if the short-term test shows radon levels over 200 Bq/m3 at any point during the testing. 

Remember - the only way to know if your home has high levels of radon is to test for it – Radon is a colourless, odorless, tasteless gas. There is no way to tell if a home has high levels by looking at it. Even if your home is brand new or your neighbour’s home tests low for radon, you may have a different level.

Does the health unit provide free radon test kits?

Unfortunately, the health unit does not provide or sell radon test kits. However, long-term test kits can be purchased from local hardware stores, as well as from a variety of online suppliers. Please visit the Take Action on Radon page to order a long-term test kit online or by phone. The cost, including lab fees can range between $30-$80.

Short-term digital test kits can be borrowed for up to 3 weeks from any open branch of the Essex County Public Library.

There are also Canadian-National Radon Proficiency Program (C-NRPP) Certified professionals in Ontario that can use specialized equipment to measure radon levels in your home. Find one at or call 1-855-722-6777. There may be more cost involved if hiring a professional to test your home compared to purchasing a do-it-yourself kit.

What is Radon?

Radon is a radioactive gas that is produced when uranium found in soil, rock or water decays. Radon is found across Canada because it occurs naturally in soil. The gas naturally rises up from the soil and can get into any type of building where it builds up due to negative pressure and lack of air flow. Breathing in radon gas for extended periods of time can potentially be hazardous to you and your family.


What are the health effects of Radon?

According to Health Canada, long-term exposure to radon is the second leading cause of lung cancer after smoking! Radon can increase your chances of lung cancer if you are a smoker.

accounts for approximately  
of lung cancer deaths in Canada

According to Public Health Ontario, approximately 13.6% of lung cancer deaths yearly in Ontario are due to radon gas exposure.

Should I be concerned about radon in Windsor-Essex County?

Health Canada recommends that if the average indoor radon concentration in a home’s normal living area is greater than 200 Becquerel’s per cubic metre (Bq/m3) then steps are necessary to decrease the radon level (Health Canada, 2014).

The Windsor-Essex County Health Unit (WECHU) completed a 3-year Radon: Know Your Level study and awareness campaign in 2018. As a part of this campaign, home owners of detached and semi-detached homes were recruited to determine indoor radon levels in the areas of Windsor-Essex County (WEC). Results showed:

  • 11% of homes in WEC had indoor radon levels above the Canadian guideline of 200 Bq/m³.
  • Essex County had a significantly greater proportion of homes with levels above 200 Bq/m3 (18%) compared to the City of Windsor (6%).
  • The average indoor radon level for WEC was 94.1 Bq/m³.
  • Amherstburg, Kingsville, Leamington and Tecumseh had average radon concentrations 12 to 26 Bq/m3 higher than WEC.
  • Newer builds (2011 or after) had the highest average indoor radon concentrations in this study1.
  • Homes with two levels (i.e. basement and main floor) had 24% and 19% higher average radon levels compared to three and four-level homes

To see the entire report, please read our 3-year radon study summary report.

Infographic illustrating how rado can enter the home.

How does Radon get into my home?

Radon gas enters into buildings through cracks in foundation walls and floors, or gaps around pipes and cables. Radon levels are often highest in crawl spaces and basements as they generally have poor ventilation and are closest to the source of entry. Although radon outdoors is diluted in the air and not a threat, in enclosed spaces like your home, it can get trapped and build up to higher levels.

Levels of radon can differ from home to home, but almost all homes will have some radon. Radon levels depend on a variety of factors including:

  • soil characteristics (presence of uranium deposits)
  • construction type (ranch, 2 story, side split)
  • foundation type (poured concrete, block, presence of crawlspaces, etc.)
  • lifestyle of occupants (window/doors are left open frequently, amount of time spent in lower levels)

The factors makes it impossible to predict radon levels in a home; the only way to know your level is to test.

What do I do if I have high levels of Radon in my home?

Steps should be taken to lower the radon level in a home whenever the average annual radon concentration exceeds 200 Bq/m3 in the normal living area (the lowest lived-in location where you spend more than 4 hours per day).

It is the sole responsibility of the homeowner to make changes to the home to reduce the harmful effects of radon. Currently, there are no government programs to help off-set the cost of radon mitigation.

If you have a new home that is less than 7 years old, you may be eligible to have the cost covered by the Tarion Home Warranty Program.

Please note: there is no level of radon exposure that is considered risk free. It is the choice of each homeowner to decide what level of radon exposure they are willing to accept and to act accordingly.

It’s recommended that the higher the radon concentrations, the sooner remediation should be done to reduce levels.

  1. Consult with a certified radon professional to determine the best radon reduction method for your home. Contact the Canadian National Radon Proficiency Program (C-NRPP) for a certified radon professional at 1-855-722-6777 or
  2. Contact Health Canada regarding your health risk questions toll free at 1-866-225-0709 or email
  3. Retest your home for radon after mitigation is complete.

For more information on radon reduction strategies, please see the ‘Radon- Reduction Guide for Canadians’ booklet on Health Canada’s website or stop by the Windsor-Essex County Health Unit between 8:30 am – 4:30 pm for a hardcopy of the booklet.