Ontario and Quebec · since 2005
Mold Testing in Ontario & Quebec
Mold testing tells you, with lab results, whether a room’s air holds more spores than the air outside, and which types. Our mold air test is $550 plus tax with the inspection and an outdoor sample included, an accredited third-party lab reads it, and results come in 2 to 5 business days. Right now you may only have a smell, a stain or a guess.
A musty smell is a question, not a diagnosis. A test answers it, when a test is what you need. Sometimes it isn’t, and we’ll tell you that too.
Since 2005 · 15,000+ inspections · IICRC certified inspectors
Mold testing at a glance
In one sentence: at a mold inspection, a certified inspector checks for moisture, samples the air inside and outside, an accredited lab counts and names the spores, and you get the answer in writing.
Last updated: 5 November 2026
A musty smell is a reason to ask about mold testing, not a diagnosis
A smell tells you something’s probably growing somewhere: behind a wall, under a floor, in a duct. It can’t tell you where, how much, or whether the air you’re breathing holds more spores than the air outside. If the smell is the whole story so far, our odour inspection page is a good place to start.
Most calls about mold testing start with one of these:
- A musty smell in the basement or a closet, or when the heat comes on in the fall, with no mold in sight.
- Water damage (a sewer backup, a roof leak, spring water in the basement) that dried slowly.
- Stains that come back on a bathroom ceiling or low on an outside wall, even after cleaning.
- Buying a home, when you’d rather have a written answer before you sign than a surprise after closing.
- Remediation work that’s just finished, and you want to confirm the air is back to normal.
But seeing mold doesn’t tell you what kind it is or how much is in the air
The mold you can see is rarely all of it, and a house with no stains at all can still have a colony in a wall cavity.
Most homes with a small patch still don’t need a lab. Health Canada says that in most situations it does not recommend testing the air for mould, and we agree with most of that. A small patch on a window sill is a job for dish soap, water and better humidity control. Health Canada’s line for small is one square metre or less in total, and it wants indoor humidity between 30% and 50%.
A test earns its price when you need to know where the mold is, how much there is, and whether to open a wall. Health Canada names that case too: concerns that stay unexplained after an inspection, especially after flooding, roof leaks or pipe leaks that may have reached wall cavities. If you’re not sure which side of that line you’re on, a virtual inspection is free inside our service area ($100 outside it or for tenants), and we’ll tell you straight whether a test is worth it.
So a mold test compares your air with the air outside, and an independent lab reads it
-
1
Day of the visit
The inspector walks the house before sampling anything
Moisture readings in the basement, bathroom and around windows, plus an infrared camera if needed. That’s the mold detection part, and it decides where the samples go.
-
2
Day of the visit
Air testing for mold, inside and outside
A pump pulls a measured volume of air through a cassette that traps spores. The outdoor sample gives the count something to be compared with, and it’s free. Where it helps, the inspector adds a tape lift or a wall-cavity sample.
-
3
Within 1 business day
You get the inspection report
What the inspector saw, the moisture readings, the photos and where each sample was taken.
-
4
2 to 5 business days
An accredited lab counts and names the spores
The analyst reading the slide has never met you and has no work to sell you. We then walk you through the results in plain language. See how our inspections work.
Tell us what you’re seeing or smelling, and we’ll tell you if a test makes sense.
Mold testing cost depends on how many rooms we sample, not the size of the house
An apartment with a smell in one bedroom is usually one indoor sample. A house with a musty basement and a stained upstairs bathroom is more like two or three. The inspection, the outdoor sample, the lab work and the report are all inside the first price. Our mold testing cost guide compares this with other companies’ prices and with tax included.
| Service | Price (CAD, plus tax) | What’s included |
|---|---|---|
| Mold air test | $550 | Visual and diagnostic inspection, 1 indoor air sample, free outdoor baseline sample, lab analysis, written report |
| Each extra sample | $260 | Another room sampled in the same visit and analyzed |
| Visual inspection only | $95 | The inspector’s visit and findings, no samples. Written report $155 more |
| Virtual inspection | Free in our service area | A video walk-through. $100 outside the service area or for tenants |
| Tape lift or wall-cavity sample | Quoted by our team | Depends on what the inspector finds on site |
One room
A bedroom that smells musty, for example.
Two rooms
The basement and the bathroom above it.
Three rooms
Three separate areas in one visit.
Call 1-866-528-2897 and we’ll work out your total. For how our prices compare with typical ranges, read the air quality testing cost guide.
But a home mold test kit gives you a hint, not an answer
Most hardware-store kits are a petri dish you leave open on a counter. Spores are everywhere, indoors and out, so a dish that grows mold in two days confirms what’s true of nearly every house.
Home kit
Tells you there are spores
- An open dish, for a rough length of time
- No outdoor sample to compare with
- You read the result yourself
Professional mold test
Tells you if you have a problem
- A measured volume of air, inside and outside
- Spores counted and named by an accredited lab
- A written report with the next step
Our take: a kit’s fine for curiosity. If you’re buying a home, someone has symptoms or you’re deciding whether to open a wall, use a lab.
Even a lab mold test has limits, and we’d rather tell you now
Canada has no health-based exposure limit for indoor mould, so be wary of anyone who says your spore count passed or failed a Canadian limit. Here’s what else people expect from a test that it can’t do.
Myth A normal air test proves there’s no mold.
Fact It shows the air that day. A colony sealed behind a wall can release few spores, which is why the inspector checks moisture too and may suggest a wall-cavity sample.
Myth The results will say whether mold is making my family sick.
Fact They can’t. Health Canada says an air test can’t predict health effects. For symptoms, talk to your doctor and bring the report with you.
Myth A black stain means toxic mold.
Fact Colour doesn’t name a species. Health Canada’s advice is the same whatever’s growing: fix the moisture and clean up the mold.
Myth A little bleach takes care of it.
Fact Health Canada says not to use bleach on mold. Dish soap and water will do for a small patch, and the job isn’t finished until the moisture’s gone.
People call asking for a test, and sometimes that’s the right call. But the first thing I want to know is where the water’s been. If a moisture reading already explains it, fix the leak and keep your money. The sample’s for when it doesn’t.
Andrey Golubev
Senior Indoor Environmental Inspector · Certified Mold Inspector (CMI) · Two decades of mold inspections
So your mold test results point to one clear next step
The report compares each room with the outdoor sample. In practice, nearly every result lands in one of these:
- Similar to outside: no active source showed up in the air that day. We check the moisture, and that’s often the end of it.
- Higher inside, or types not found outside: there’s probably a source. The report says where to look and what to do, such as opening a section of wall or hiring a qualified remediation contractor.
- After remediation: a new test confirms the air is back to outdoor levels before the walls close up or you move back in.
Home built before 1990, and you may have to open a wall? Have the materials checked first with asbestos testing. We’ll do both in one visit. For how we research and review what we publish, see our editorial policy.
- Since 2005 testing homes in Ontario and Quebec
- 15,000+ inspections
- IICRC Certified
- IAC2 Certified
- IAQA corporate member
We do mold testing and mold inspections across Ontario and Quebec
For local detail, see mold inspection and testing in Ottawa, Montreal, Toronto, York Region and Durham, Mississauga and Peel and Oakville, Halton and Hamilton. All of our air quality testing services use the same accredited lab process.
Customer stories and reviews
I am pleased with the air quality testing for mold that I received. The company was very professional and the product was delivered quickly. I would recommend them to anyone who needs this type of service.
By Antonio H.
I wanted to share my experience with air quality testing for mold. I was looking for a way to get the best air quality testing for mold and I found this great company that had a lot of great reviews. I was able to get a great deal on their service and it was worth every penny. They were very professional and did a great job. Would recommend!
By Ryan H.
I have been struggling with allergies for the past few years. I finally decided to get tested for mold in my home. Air Quality Testing came to my house and took samples of the air in my home. They then did a detailed analysis of the air quality in my home, which included looking for mold.
By Kristine H.
Mold testing questions we hear most
You start with the moisture, then sample if the question’s still open. Our inspector checks the walls, basement, bathroom and windows with a moisture meter, then pumps a measured volume of air through a spore trap, inside and outside. An accredited lab counts and names the spores. See how an inspection works.
No. A mold inspection is the walk-through: moisture readings, photos and where the water’s been. A mold test adds samples and lab analysis. A visual inspection is $95 plus tax, with a written report for $155 more, and the $550 air test includes both. If you can already see the cause, the inspection alone is often enough.
It’s $550 plus tax for one room: the visual and diagnostic inspection, one indoor air sample, a free outdoor baseline sample, lab analysis and a written report. Each extra sample is $260, so two rooms come to $810 and three to $1,070. Our air quality testing cost guide covers the wider picture in Canada.
The written inspection report comes within 1 business day of the visit. Lab results follow 2 to 5 business days after sampling, and surface samples usually come back faster than air samples. Rush analysis is available for an added fee. We’ll then explain the numbers in plain language, or you can read our guide to understanding air quality test results.
Usually not. If the patch is small (Health Canada’s line is one square metre or less in total) and you know where the water came from, fix the moisture and clean it with dish soap and water. Call us if it comes back, if it’s bigger than that, or if you can’t find the source.
No. A mold test counts spores and names the types, and Health Canada says an air test can’t predict health effects. If someone has symptoms, talk to your doctor and bring the report along. Either way, mold growing indoors should be cleaned up and the moisture behind it fixed.
They confirm there are spores, which is true of every house. Without a measured volume of air, an outdoor sample and a lab, a kit can’t tell you whether you’ve got a problem. For a purchase, a renovation or symptoms, use a lab test. Our guide to home test kits covers the options.
You can know instead of guess.
One visit, one sample inside, one outside, and an accredited lab puts the answer in writing.
Phone open 24/7 · Inspections Monday to Friday, 8 AM to 5 PM · Response within 1 business day