How to Test Your Home for Radon in Canada

Testing your home for radon in Canada is one of the simplest important things you can do for long-term indoor air safety. Radon cannot be seen, smelled, or tasted, so there is no reliable way to guess whether your home has a problem. The only way to know is to test.

The good news is that radon testing is not complicated. Most homeowners can do it themselves with a long-term test kit, or they can hire a certified radon measurement professional to handle it for them. The part that matters most is not making it complicated. It is making sure you test the right way, in the right place, for the right amount of time.

That is especially important in Canada because Health Canada’s radon system is built around long-term testing. This is not a topic where a quick weekend test usually gives you the full answer. Health Canada wants homeowners to compare the national guideline against a result that reflects real long-term exposure, not just a short snapshot.

This guide walks through the process step by step, from choosing the right type of test to placing the detector correctly, reading the result, and deciding what to do next.

Table of Contents

• Why every Canadian homeowner should test
• Step 1: Choose how you want to test
• Step 2: Use a long-term test, not a quick test
• Step 3: Pick the best time of year
• Step 4: Place the device in the right spot
• Step 5: Start the test correctly
• Step 6: Leave it in place long enough
• Step 7: Finish the test and get your result
• Step 8: Understand what the number means
• Step 9: Know what to do if the level is high
• Common testing mistakes to avoid
• Bottom line for homeowners
• Sources

Why every Canadian homeowner should test

Health Canada says every home in Canada should be tested for radon. That is because radon is found across the country, levels vary widely from one house to another, and there is no way to know your home’s level based only on location, age, or appearance.

Many homeowners still assume radon only affects very old homes, very rural homes, or homes in a few high-risk areas. That is not a safe assumption. A new home can have high radon. A well-maintained home can have high radon. Two homes on the same street can have very different results.

Testing matters because Canada’s radon guideline is based on measured exposure, not guesswork. If your home is above the guideline, Health Canada recommends corrective action. If it is below the guideline, that is good to know too. Either way, the test gives you a real answer instead of a guess.

Step 1: Choose how you want to test

In Canada, there are two main ways to test your home for radon.

The first option is to buy a do-it-yourself long-term radon test kit. This is the route many homeowners choose because it is simple and relatively inexpensive. The kit is placed in the home, left in the proper location for the required test period, and then returned to a lab for analysis.

The second option is to hire a radon measurement professional certified under the Canadian National Radon Proficiency Program, or C-NRPP. This can be a good choice if you want professional help from the start, if you are not comfortable managing the test yourself, or if you are dealing with a more complicated property.

Health Canada recognizes both options. If you hire someone, it recommends making sure the person is certified and that the test they perform is a proper long-term test. If you want to find a certified professional, the most direct place to look is C-NRPP’s Find a Professional page.

If you want to run the test yourself, Health Canada’s homeowner testing page is here: Testing Your Home for Radon.

Step 2: Use a long-term test, not a quick test

This is one of the most important parts of the entire process.

Health Canada says it is important to conduct a long-term test for a minimum of 3 months. Its technical measurement guide says home testing should run for at least 91 days. The reason is simple: radon levels change over time. They rise and fall with weather, ventilation, pressure differences, and how the home is being used. A short test can miss the bigger picture.

In Canada, the long-term result is what should be used to compare against the national radon guideline. Health Canada specifically says short-term measurements should never be used to determine whether a home exceeds the Canadian guideline or whether remedial action is needed.

That surprises some homeowners because quick radon tests are widely discussed online. But in the Canadian homeowner framework, the best practice is clear: use a long-term test if you want a meaningful home decision.

If you want to read Health Canada’s wording directly, these are the best references:

Radon Reduction Guide for Canadians

Guide for Radon Measurements in Homes

Step 3: Pick the best time of year

Health Canada recommends that homeowners do a long-term test during the fall or winter. More broadly, that means during the heating season.

This matters because radon levels are usually more useful for decision-making during colder months, when homes are more closed up and conditions are more likely to reflect the kind of indoor environment where radon can accumulate. Health Canada’s more technical guidance says that testing outside the heating season can underestimate the average annual radon level.

For most homeowners, the easiest practical answer is to start a test sometime in the fall or winter and let it run for at least three months. That lines up best with the Canadian testing framework.

If it is currently summer, that does not mean you should forget about radon. But if there is no urgent reason to test immediately, fall or winter is generally the better time to start.

Step 4: Place the device in the right spot

Placement matters almost as much as test duration.

Health Canada says the device should be placed in the lowest lived-in level of the home. In plain English, that means the lowest level where people actually spend time on a regular basis. Its current homeowner materials describe this as the lowest level where homeowners spend at least 4 hours per day.

That could be a finished basement family room, basement office, basement bedroom, lower-level playroom, or the main floor if the basement is unfinished and not regularly used. The right location depends on how the home is actually lived in.

Health Canada’s current placement guide also gives very practical instructions about where the device should and should not go.

Do place the device:
On the lowest lived-in level, at breathing height, on a flat surface such as a table, shelf, or desk, or hung according to instructions.

Do not place the device:
In kitchens, bathrooms, laundry rooms, closets, or unfinished basements. Do not place it near windows, doors, vents, exterior walls, fireplaces, direct sunlight, appliances, or electronics.

That last part is important because a poorly placed detector can give you a less useful result even if the test is long enough.

Health Canada’s updated placement guide is here: How to Use an Electronic Radon Monitor or a Long-Term Detector.

Step 5: Start the test correctly

Once you have the right device and the right location, the next step is simply to start the test according to the instructions.

If you are using a long-term detector, open the package only when you are ready to begin, record the start date, time, and location, and keep the kit materials somewhere safe. That includes the instructions and return packaging.

If you are using an electronic radon monitor, Health Canada says to choose one that has passed C-NRPP performance testing for long-term radon measurements in homes. This is an especially important detail because not every consumer device on the market is equally appropriate for Canadian long-term home testing.

If you are buying an electronic monitor, the safest approach is to stick with one that meets C-NRPP performance expectations and then follow the manufacturer’s setup instructions carefully.

Step 6: Leave it in place long enough

Once the test has started, the most important thing is patience.

Health Canada says the device should remain in place for at least 3 months. Longer is acceptable in many cases, up to 12 months, but 3 months is the minimum homeowner target that fits the Canadian long-term testing framework.

For a passive long-term kit, that means leaving it alone and not moving it around. For an electronic radon monitor, it means letting it run continuously and waiting until you have a true long-term average reading rather than reacting to short-term fluctuations on the display.

One of the easiest mistakes homeowners make is getting nervous after a few days or few weeks and trying to interpret an incomplete number. That is not how the Canadian system is designed. The goal is the longer-term average, not the early fluctuation.

Step 7: Finish the test and get your result

At the end of the test period, what you do next depends on the type of device you used.

If you used a long-term detector kit, you will usually need to record the end date and time, seal the detector as instructed, and mail it to the laboratory identified in the kit instructions. The lab will analyze the device and report the average radon level.

If you used an electronic radon monitor, Health Canada says you should check the long-term average reading after 3 months by following the manufacturer’s instructions. Some monitors can continue running for ongoing monitoring after that.

Either way, keep a record of the result. It is useful to keep both the number itself and the date range of the test on file for future reference.

Step 8: Understand what the number means

Once you get your result, the next step is to compare it with the Canadian radon guideline.

Health Canada’s guideline is 200 Bq/m³. It says homeowners should take corrective action if the average annual radon level exceeds 200 Bq/m³ in the normal occupancy area of the building.

If your result is below 200 Bq/m³, that is good news, but it does not mean radon is risk free. Health Canada says no radon level is considered risk free. It simply means your home is below the level where corrective action is officially recommended.

If your result is above 200 Bq/m³, Health Canada recommends taking action to reduce it. The higher the level, the sooner action should happen.

The official guideline page is here: Government of Canada Radon Guideline.

Step 9: Know what to do if the level is high

If your home tests above the guideline, the next step is not panic. It is mitigation.

Health Canada says that if your radon level is above 200 Bq/m³, you should lower it within 1 year, and sooner if the concentration is substantially higher. It also says radon in most homes can be reduced by more than 80% and that effective techniques are available.

For most homes, the usual solution is some form of active soil depressurization or sub-slab depressurization installed by a trained professional. Health Canada recommends using a C-NRPP-certified mitigation professional because reducing radon properly requires technical knowledge and specific skills.

If your level is high, these are the best next steps:

1. Keep your test result and date range.

2. Use C-NRPP to find a certified professional.

3. Get quotes or an assessment.

4. Plan mitigation.

5. Re-test after mitigation to confirm the level has been reduced.

Health Canada’s homeowner mitigation page is here: Reducing Radon Levels in Your Home.

Common testing mistakes to avoid

Using a short-term test as your final answer.
In Canada, short-term measurements should not be used to decide whether the home exceeds the guideline or needs remedial action.

Putting the device in the wrong location.
An unfinished basement, laundry room, bathroom, or spot near a window or vent is not the right place.

Moving the detector during the test.
Once the test starts, leave it in the chosen location for the full test period.

Choosing the lowest level instead of the lowest lived-in level.
Health Canada focuses on the lowest level actually used as living space, not just the physically lowest slab or utility corner.

Forgetting to mail the detector back.
A passive long-term kit does not give you a result unless it is sent to the lab after the test period ends.

Buying the wrong electronic monitor.
If you use an electronic radon monitor, Health Canada says to choose one that has passed C-NRPP performance testing for long-term measurements in homes.

Ignoring a high result because the home “seems fine.”
Radon has no smell, taste, or visible warning sign. The number matters more than the feeling of the space.

Bottom line for homeowners

Testing your home for radon in Canada is not complicated, but it does need to be done correctly.

The safest and clearest approach is this: choose either a DIY long-term test kit or a C-NRPP-certified measurement professional, test for at least 3 months during fall or winter, place the device in the lowest lived-in level of the home, leave it in place for the full test period, and then compare the result to the Canadian guideline of 200 Bq/m³.

If the result is below the guideline, keep the record and consider re-testing later if the home changes. If the result is above the guideline, start planning mitigation with a certified professional.

That is the Canadian radon testing process in a nutshell. Simple, practical, and worth doing.

Sources

• Health Canada: Testing Your Home for Radon
• Health Canada: How to Use an Electronic Radon Monitor or a Long-Term Detector
• Health Canada: Radon Reduction Guide for Canadians
• Health Canada: Government of Canada Radon Guideline
• Health Canada: Guide for Radon Measurements in Homes
• Health Canada: Radon, What You Need to Know
• Health Canada: Reducing Radon Levels in Your Home
• C-NRPP: Find a Professional
• C-NRPP: Certification Check