Trust the long-term result. For radon testing in Richmond Hill, Health Canada treats a test of at least 91 days—ideally three to twelve months, with at least 91 of those days in the heating season—as the measurement you compare with the guideline of 200 Bq/m³. A short-term test, meaning anything shorter than 91 days, can swing with weather and how the house is being used that week, and Health Canada says short-term measurements are not appropriate for deciding whether to lower radon. That applies in Oak Ridges and around Mill Pond as much as in Richmond Hill’s newer subdivisions, because radon comes from the soil under the house, not from the home’s age. At Golden Home Inspections we test for radon as part of our home hazard testing. Your inspector is Yama Nehan, a Certified and Registered Home Inspector with about 15 years of home inspection experience and a construction engineering degree from George Brown (Building Renovations). Call 647-704-7100 to book.
Key takeaways
- Radon is a naturally occurring, colourless and odourless gas from the breakdown of uranium in soil and rock. Home age and neighbourhood do not predict your level.
- Health Canada defines a long-term radon test as at least 91 days and recommends a test of 3 to 12 months, with at least 91 days falling in the heating season.
- A short-term test lasts less than 91 days. Health Canada says short-term measurements are not appropriate for informing decisions about lowering radon.
- Compare a valid long-term result with Health Canada’s guideline of 200 Bq/m³. If the result is above that level, Health Canada recommends taking corrective action within 1 year, and sooner when the number is higher.
- Place the detector in the lowest lived-in level of the home, in a room where someone spends more than 4 hours a day. Skip kitchens, bathrooms and laundry rooms.
- Radon detectors are analysed by accredited labs.
Does every Richmond Hill home need radon testing?
Yes. Oak Ridges, the streets around Mill Pond and Richmond Hill’s newer subdivisions should all be tested, because radon enters wherever the house meets the ground—cracks in a slab, gaps around pipes, sump pits, floor drains and the joint between floor and wall. A newer, tighter home can hold indoor air longer in winter, so a recent build can test higher than an older house nearby, and the reverse is just as common. Health Canada recommends testing every home, whatever its age or location. For what a full visual inspection covers in town, see our Richmond Hill home inspector page. Our home hazard testing page for Toronto and the GTA covers radon alongside asbestos, vermiculite and mould testing.
What is the difference between a short-term and a long-term radon test?
Time is the difference that matters. Health Canada defines a long-term radon test as a measurement of at least 91 days and a short-term test as anything shorter than that. Only the long-term average is meant to be compared with the 200 Bq/m³ guideline, because radon levels rise and fall with weather, closed windows and how the house is being heated.
| Short-term radon test | Long-term radon test | |
|---|---|---|
| How long it runs | Less than 91 days | At least 91 days. Health Canada recommends 3 to 12 months |
| What it measures | A snapshot that can swing with weather, open windows and how the house is used that week | A closer estimate of the home’s average annual radon level |
| Heating season | A short stretch may miss the colder months, when indoor radon is often higher | Health Canada advises that at least 91 days of the test fall in the heating season |
| Use with the 200 Bq/m³ guideline | Not appropriate for deciding whether to lower radon | The result you compare with Health Canada’s guideline |
| Typical next step | Follow up with a long-term test | Compare the lab result with 200 Bq/m³ and plan any reduction work from that number |
The details are in Health Canada’s radon guideline and its guide to radon measurements in homes.
When is a short-term radon test still useful?
As a rough snapshot only—not as the number you use to decide on reduction work. A brief reading during a busy week of house-hunting in Richmond Hill can spark a useful conversation, but Health Canada is clear that the guideline applies to your average annual radon level, not to short-term measurements. If you already ran a short test, treat that result as a reason to book a proper long-term test after you move in, not as a final answer.
How does our radon testing work in a Richmond Hill home?
We start by choosing the right room. In most Oak Ridges, Mill Pond and newer-subdivision houses, that is the lowest level where someone regularly spends more than 4 hours a day—a finished basement family room, a basement bedroom or a basement apartment. Health Canada advises against placing a detector in a kitchen, bathroom or laundry room, and against putting it on the floor, against an exterior wall, or next to windows, doors, heating vents or a sump. The detector sits in the breathing zone, with space around it for normal airflow, and you live as you normally would for at least three months. The detector is then sealed and analysed by an accredited lab, and we explain the result in plain language.
What should you do with your Richmond Hill radon result?
Use only a valid long-term average when you compare your number with Health Canada’s guideline of 200 Bq/m³ (becquerels per cubic metre):
| Long-term result | What Health Canada recommends |
|---|---|
| At or below 200 Bq/m³ | No corrective action is required. Health Canada encourages keeping levels as low as reasonably achievable, and retesting after major renovations. If fewer than 91 days of the test fell in the heating season, the result may underestimate the annual average, so a retest in the next heating season is recommended. |
| Above 200 Bq/m³ | Take corrective action within 1 year. The higher the result, the sooner you should act, and the work should reduce the level as much as is practicable. |
The most common way to lower radon is an active soil depressurization system: a pipe and fan draw soil gas from under the basement floor and vent it outside. Sealing a sump pit, floor drains and visible cracks usually forms part of the job. Once that work is done, run another long-term test to confirm the level has come down, and keep both lab reports with your home records.
A situation we often see in Richmond Hill
A buyer or new owner in Oak Ridges or a newer subdivision runs a short radon test during showings or in the first week after moving in, then treats that single number as the final word. Because radon rises and falls from one week to the next, that snapshot can look reassuring or alarming for reasons that have more to do with the weather than with the house. The clearer sequence is to complete the home inspection as usual, then place a long-term detector in the lowest lived-in room over the heating season and wait for the accredited lab result before deciding whether any reduction work is needed.
What affects the cost of radon testing in Richmond Hill?
Cost depends mainly on how many detectors the home needs—a house with a separate basement apartment may need more than one—and on whether you combine radon testing with a home inspection or other hazard testing. The final price depends on the home, so call us for a quote rather than guessing from a neighbour’s project.
Frequently asked questions
Is radon testing included in a standard home inspection in Richmond Hill?
No. A standard home inspection is visual and lasts a few hours. Radon testing needs a detector in place for at least 91 days, then lab analysis. Many buyers book the long-term test once they move in, or ask whether a previous long-term result already exists for the house.
I already did a short-term test. Do I still need a long-term one?
Yes, if you want a result you can compare with Health Canada’s 200 Bq/m³ guideline. Health Canada says short-term measurements are not appropriate for informing decisions about lowering radon, and that the minimum test length for a valid estimate of the average annual level is 91 days.
Where should the detector go in a house with a finished basement?
In the lowest lived-in level, in a room where someone spends more than 4 hours a day—a basement bedroom, family room or apartment, not a furnace room, storage area or unfinished space you rarely enter. Keep the detector off the floor, away from exterior walls, windows, doors and heating vents, and out of kitchens, bathrooms and laundry rooms.
Should I change how I live in the house during the test?
No. Health Canada advises that residents should not alter their lifestyle during a long-term radon test. Live normally, including how you heat the house, so the result reflects the way you actually use the home.
Planning radon testing in Richmond Hill, including Oak Ridges, Mill Pond and newer subdivisions? Call 647-704-7100 or email contact@goldenhomeinspections.ca to book with Golden Home Inspections, based in Toronto, Ontario. Hours are 9 AM–8 PM, seven days.
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