Health Canada recommends all homes be tested for radon using a long-term radon test in the heating season. Since long-term exposure to elevated levels of radon poses a serious health risk, and radon levels can change daily, it is best to test for radon with a long-term test of 91 days or more. For most single-family homes, duplexes or apartments, you only need to test in one room (for homes with larger square footage you may want to consider testing in two different areas).
THINKING OF RENOVATING?
We recommend testing for radon before renovating your home and including the cost of a mitigation system in your renovation plans.
We recommend that you test your home for radon after any renovations that include changes such as increasing insulation in the home, changing windows, replacing your heating system or improving air-tightness of your building envelope.
By hiring a C-NRPP certified professional to conduct the testing for you, you can ensure that tests are properly placed. A professional will provide you with the information you need in a way that is easy to understand so you can be assured of your family’s safety, and that of your home, for years to come. Find a list of certified professionals here.
MOVING INTO A NEW HOME?
We recommend that you test for radon during the first heating season that you live in a home. Moving or building a new home? Consider testing for radon to be a priority during your first year.
PURCHASING A NEW HOME?
A person purchasing a home which does not have a radon mitigation system installed, may want to know if they will need to install a radon system once they move into the house. A short-term radon screening could be conducted to provide some insight as to whether a radon mitigation may need to be installed. CARST has developed guidelines to be followed in the document “Guidelines for Conducting a Radon Screening Assessment as Part of a Real Estate Transaction of a Residential Dwelling in Canada”. Contact a C-NRPP professional for help.
We recommend conducting a long-term test once you move into the new home to confirm whether or not a mitigation system is required.
Not sure how to test? We have certified professionals to help. Find a professional here.
HOW TO TEST?
Pick a room, pick a spot, record the information!
Then return the test at the end of 91 days.
Health Canada has developed guidelines on how and where to place tests, and C-NRPP has developed a list of devices which meet the set criteria for use. If you purchase a detector to place yourself, ensure it is on the C-NRPP List of Homeowner Devices – it may have the C-NRPP logo on the device or check our list.
Each device should include detailed instructions on where to place the test and how to get the results.
You can hire a professional who is certified with the Canadian National Radon Proficiency Program (C-NRPP) to conduct the testing for you. A C-NRPP Professional will ensure that your tests are placed properly and will provide you with the information in a way that is easy to understand. The more you understand about Radon exposure the more you can ensure you and your home’s safety for the future.
What tests should I use?
C-NRPP Listed Professional Devices are devices which are listed by C-NRPP and approved for C-NRPP Measurement Professionals to use when conducting tests. You can hire a C-NRPP Measurement Professional to test for your or purchase a test for a do-it-yourself measurement. Look for a device that is on the C-NRPP list.
The tests do not have any chemical or harmful materials inside which would be spilled if knocked over or touched. For each of the devices, the manufacturer will provide instructions on how and where to place the test, how long the optimal duration for the test device is and how to receive the results of the radon test.
Long- and Short-term C-NRPP Listed Professional Devices will need to be analyzed by an analytical provider, and so the instructions should provide information on how to return the test for analysis.
In Canada radon is measured in becquerels per cubic meter. (Bq/m3)
Becquerel is a measurement of radioactivity. Therefore, a Bq/m3 provides a measurement of radioactivity in a unit volume of air. This provides us with an understanding of how much radiation is present in an area.
How many tests do I need?
For a single-family home, duplex or apartment you only need to test in one room. If your home has a large square footage you may want to consider two tests in order to test in two different areas in the occupied area of your home.
Also: You may want to use 2 tests for better accuracy.
When a professional conducts testing, they follow proper Quality Assurance protocols with duplicate tests to verify precision of tests. If you hire a professional, they will make sure that this is included in their Quality Assurance protocols.
How long does the test need to be?
This is a test that lasts for more than 91 days. It could be from 91 days to one year.
This type of test can be done using a single-use long-term test device, though some homeowners may choose to use a digital detector or home radon alarm which stays in a home for 91 days or longer.
The purpose of the long-term test is to provide an annual average of your radon exposure. Since radon levels fluctuate day-to-day and season-to-season, a long-term test will provide an average of what the radon levels have been throughout those changes.
Short term tests:
Since radon levels are so variable, it is important to conduct a long-term radon test before deciding whether to mitigate your home. However, there are a couple of situations where a short-term radon test of between 96 hours and 90 days may be useful, such as verifying that a radon mitigation system is functioning as designed.
You can find more information here: Measurement – Decision to Mitigate
Post Mitigation Test:
If you have installed a mitigation system into your home, a certified mitigator should do a short-term radon test to ensure the system is effective in lowering the radon levels in the home. This can be done using a professional Continuous Radon Monitor, C-NRPP Listed Professional Device short term test device or with an Electronic Integrating Device, left in the home for a minimum of 48 hours. Once you have conducted a short-term test you should conduct a long-term test during the following heating season to confirm the effectiveness of the mitigation system.
Real Estate Decisions:
A person purchasing a home which does not have a radon mitigation system installed, may want to know if they will need to install a radon system once they move into the house. A short-term screening could be conducted to provide some insight as to whether a radon mitigation may need to be installed. We recommend conducting a long-term test once you move into the new home to confirm whether or not a mitigation system is required.
Radon testing during the heating season (October through April) over several months (91 days and longer) is recommended by Health Canada for all houses across Canada. Ideally, a home listed for sale would already have been tested for radon and mitigated as required. C-NRPP recommends that radon measurement reports should be provided as part of the seller’s declaration/disclosure statements and should indicate that a long-term radon measurement of at least 3 months’ duration was performed. Any home with a radon concentration above Health Canada’s Action Level of 200 Bq/m3 should be mitigated. In many cases, however, a home that is listed for sale has not previously been tested for radon. CARST has developed guidance on how these homes may be screened for radon during a real estate transaction.
Guideline for Conducting a Radon Screening Assessment as Part of a Real Estate Transaction of a Residential Dwelling in Canada
The minimum duration of a radon screening assessment is 4 days.
It is important to note that every home can be fixed. Therefore, even if you aren’t able to conduct a radon test before you decide to purchase a house, you can measure the radon levels after you move in and reduce radon levels in home if necessary after you move in. See CREA’s A Homeowner’s Guide to Radon.
Discuss this with your real estate agent, or contact the real estate association in your area.
WHAT DOES MY TEST REPORT MEAN?
The health risk from radon is lower if levels are below 200 Bq/m3 and therefore, Health Canada recommends that further action to reduce radon levels is not necessary. It should be noted that, while the health risk from exposure at levels below the Canadian Guideline is lower, it may be possible to reduce it even further through installation of a mitigation system. It is the homeowner’s choice to decide and reduce at the desired level of radon exposure.
If the long-term measurement results are greater than 200 Bq/m3, then Health Canada has provided some suggestions of time frames for mitigation, they also recommend that when mitigation measures are taken, they reduce levels to as low as practicable.
|Radon Concentration||Recommended Remedial Action Time|
|Greater than 600 Bq/m3||In less than 1 year|
|Between 200 Bq/m3 and 600 Bq/m3||In less than 2 years|
|Between outdoor levels and 200 Bq/m3||At homeowner’s discretion|
The Average Outdoor Radon Concentration is 15 Bq/m3
|Test is less than 91 days||If your test duration was less than 91 days, you may want to follow up with a long-term test conducted with a during the heating season, as per Health Canada Guidelines to base a decision of mitigation.|
|Test is conducted with more than 50% of the duration outside of the ‘heating season’ (October 1 – April 30)||If your test was below 200 Bq/m3 but conducted outside of the heating season of October to April, you may want to consider retesting.
If the test was conducted with windows open for a significant portion of the test days, you may want to consider re-testing.
Health Canada recommendations are that the test be conducted during the heating season from October thru to April.
RADON IN WATER
Radon also may be present in the water supply of a home. As the water is used in a home through a tap, shower, or appliance the water aerates and releases the radon into the air.
If you have tested your home air for radon and find that levels are elevated and you are on a system that uses water from a well, you may want to consider testing the radon levels in the water.