What mould removal costs in Ottawa, and what sets the price.
Published mould removal prices that cover Ottawa run from $500, the bottom of one national guide's bathroom range, to $35,000 or more, the top of one Ottawa company's whole-house range. Mold Busters, a mould removal company working in Ottawa, lists average Ottawa costs of $1,500 to $2,500 for minor mould on a small area, $2,500 to $7,500 for a larger area or several rooms, and $7,000 to $15,000 or more once mould has gone deep into the building. Where a job lands depends on four things: how much area is affected, where in the house it is, what is behind the drywall, and whether the water feeding it has been fixed. None of these figures is ours. We quote after seeing the space.
Not sure how big it is?
Send photos and say where the mould is. We will tell you which of Health Canada's size bands it falls in before anyone quotes a figure.
(613) 852-4059The published prices, and what each one describes.
Two companies publish mould removal prices that cover Ottawa, and we read both pages on 2026-09-30. Mold Busters keeps a page of average Ottawa costs, last updated 2026-09-21. Mold Inspection Canada, which publishes moldinspection.ca, keeps a national guide to 2026 Canadian prices, updated the same day. Neither gives an Ontario average, and neither is our price list. We do not publish one.
Mold Busters sorts its Ottawa averages by how far the mould has gone. Basic removal, for minor mould on a small area, is $1,500 to $2,500. Moderate removal, for a larger area or several rooms, is $2,500 to $7,500. Advanced removal, where mould has gone deep into building materials and structure, starts at $7,000 and runs to $15,000 or more. It puts an Ottawa inspection with testing anywhere from free to $500.
Mold Inspection Canada sorts by room and gives a low, typical and high price for each. Mould on visible bathroom tile and grout is $500 to $1,500, typically $1,000. A small, dry basement is $500 to $4,000, typically $1,500. A whole house is $10,000 to $30,000, typically $20,000.
On the same job, the two disagree. Mold Busters puts an Ottawa bathroom at $1,500 to $3,000, against Mold Inspection Canada's national $500 to $1,500. For a wall, Mold Busters says $1,500 to $4,000, while Mold Inspection Canada's range runs to $20,000 a room. The wall gap has a cause: a stain on the painted face of a wall and mould through the back of it are different jobs, priced differently.
Size decides who does the work, and how it is sealed off.
Health Canada's guide to addressing moisture and mould indoors sorts mould by area. Three patches or fewer, totalling less than one square metre, is small, and the guide says a small amount may be cleaned up using proper procedures and protective equipment. More than three patches, or between one and three square metres, is medium: an expert assessment is recommended, though it may still be cleaned up with proper precautions. A single patch larger than three square metres is large, and needs an expert assessment and cleanup.
That chart is the first place to save money, because under a square metre the job may be yours. Health Canada's kit is a well-fitting disposable N95 respirator, safety glasses or goggles, and household gloves. For hard surfaces, it says to scrub with a cloth and an unscented soap solution, then dry completely and quickly.
Above the small band, the price follows the containment. The Environmental Abatement Council of Canada's mould abatement guideline sets its thresholds at 10 and 100 square feet, about one and ten square metres. From 10 square feet up, it calls for a taped enclosure of polyethylene sheeting held under continuous negative pressure, at least 5 pascals and at least four air changes an hour, and a qualified health and safety professional consulted before work starts. Past 100 square feet, each project follows a site-specific work plan written by that professional. Each level adds equipment and set-up time before any mould comes off the wall.
Ducts get their own rule. The same guideline treats less than 10 square feet of mould inside an HVAC system as medium-level work, and anything more as large. Both companies price duct and HVAC work above a bathroom: $2,500 to $7,500 in Mold Busters' Ottawa averages, $3,000 to $10,000 in Mold Inspection Canada's national figures.
Where it is: attics, crawl spaces and basements.
Mold Busters also prices by where the mould sits. Its Ottawa averages are $1,500 to $5,000 for an attic, $1,800 to $5,000 for a crawl space, $1,800 to $6,000 for a basement and $1,500 to $4,000 for concrete walls.
Attic mould follows winter. Mold Inspection Canada describes the pattern: warm indoor air leaks through pot lights, bathroom fans and attic hatches, hits the cold roof sheathing and condenses, and by spring the underside of the plywood has grown mould. It puts a typical Canadian attic job at $2,000, in a range of $1,000 to $4,000, and says removing contaminated insulation adds $500 to $1,500 on its own.
Crawl space prices swing widely. Mold Inspection Canada's range for one runs from $500 to $10,000, and it says those jobs scale with whether the moisture problem underneath is solved at the same time.
Mold Inspection Canada calls basements the most common Canadian remediation job. Health Canada's advice for them is to run a dehumidifier in damp areas, and whenever moisture condenses on cold surfaces or relative humidity passes 50 percent. In a basement, a bare concrete wall and a finished wall are priced very differently.
What is behind the drywall decides the bill.
Health Canada's guide says that if the mould is underneath the paint, the drywall will need to be removed and replaced. Mould on the painted face of a wall can be cleaned. Mould under the paint, or on the back of the board, means the board comes out.
Mold Inspection Canada puts numbers on that difference. For basements, it writes that square footage matters less than what is behind the wall, and that a finished basement with hidden mould behind a vapour barrier is the most expensive case short of a whole house. For mould on the cavity side of a wall, usually found after a slow plumbing or roof leak, it lists the drywall coming down, the insulation removed and bagged, the framing dried with dehumidifiers for 5 to 14 days, and everything rebuilt. It calls that a $5,000 to $15,000 job for one room.
Removal also reaches past the stain. The abatement guideline says to remove porous material such as drywall and ceiling tile at least 30 cm beyond the visible contamination in every direction. A patch 25 cm across means cutting out a piece at least 85 cm across.
Hidden mould is hard to price before the wall is open. When there is a strong, musty smell with no clear sign of water damage or mould, Health Canada suggests consulting a professional about hidden mould inside walls and ceiling or floor cavities. Until the wall is open, any figure for what is inside it is an assumption, and a fair quote says which parts are assumed.
Then check what the price covers after the removal. Mould removal ends with the mouldy material out and the structure dry. New drywall, insulation and paint are a rebuild, and Mold Busters lists structural repairs as a cost added to the overall bill.
Testing: when it is worth paying for.
Testing is the line on a quote most worth questioning. Health Canada's guide says that in most situations it does not recommend testing the air for mould, because an air test does not provide information that can predict health effects and often says little about the cause of the damage. Its residential indoor air quality guideline for moulds adds that, with no exposure limits, tests for fungi in the air cannot be used to assess risks to the health of the people living there.
The guide allows one exception. Where concerns remain unexplained after an inspection for dampness and mould, especially with a history of flooding, roof leaks or pipe leaks, a qualified professional may recommend testing. The point of that test is to find growth you cannot see.
Mold Inspection Canada puts a typical inspection in Ottawa, Kanata and Gatineau at $250 to $400, with lab results in 48 hours. Its national tiers are $150 to $250 for a visual inspection with a moisture meter and thermal camera, $250 to $400 for a standard one with an indoor and an outdoor air sample, and $500 to $700 for multi-room sampling with a species-level report. Mold Busters puts an Ottawa inspection with testing at free to $500.
Skip the species report. Mold Inspection Canada says lab identification to confirm which black-coloured mould is present adds $100 to $200. Health Canada's guideline says its recommendations, to control humidity, repair water damage and clean the mould thoroughly, apply regardless of the mould species growing in the building. Knowing the species does not change what comes out of the wall.
One test does earn its fee on a big job. Where extensive cleanup involves structural elements like walls, Health Canada says the company should recommend you consider a separate company for a post-remediation clearance study, to check that the mould was removed correctly and the moisture dealt with. We do not run clearance sampling ourselves, and on a job that size we will say so.
Worth paying for, and what to decline.
Professional remediation pays off on large or hidden mould. Health Canada's chart says a single patch over three square metres needs an expert assessment and cleanup, and mould behind a wall cannot be sized from inside the room. A small patch on a painted ceiling is different: the same chart lets a small amount be cleaned up with proper procedures and protective equipment.
Spend your money on finding and stopping the water, containment sized to the area, removing porous material that cannot be cleaned, drying the structure, and getting the waste out of the house. One of Health Canada's markers of a qualified company is that it prioritises removing damaged materials over trying to seal or chemically treat them.
Decline bleach, which Health Canada says not to use to clean up mould, and paint or sealant over growth in place of removal. Decline an air test with no question behind it, and a species report when the removal would be the same either way.
Mould removal can also cost almost nothing. For a patch under one square metre, the bill is a respirator, goggles, gloves and soap. It climbs with hidden growth and with a leak nobody fixed.
When insurance may pay, and when it will not.
A home policy may cover part of the bill, depending on where the water came from. The Insurance Bureau of Canada, the national association of Canada's home, car and business insurers, lists water damage from the sudden and accidental escape of water from a plumbing, heating, sprinkler or air conditioning system among the insured perils of a home policy. It calls gradual deterioration natural and expected, and not an insured peril. Our guide on whether home insurance covers mould in Ontario goes through sewer backup, overland water, condos, tenants and the claim steps.
Call your insurer before any mouldy material is torn out. IBC's claim steps say to keep damaged items unless they are dangerous or pose a health hazard, and to confirm with your insurer before disposing of damaged property.
Can you kill mould for good?
Only by taking away its water. Health Canada's guide says that unless the cause of the moisture problem has been identified and solved, mould will reappear, and that mould coming back after cleaning usually means the source of moisture has not been removed. The abatement guideline makes the same point for contractors: its procedures do not address the cause, and it cautions that the cause be investigated and fixed before the abatement is finished. So the job is to take the growth out, dry the building and stop the water.
The clock is short. Health Canada says mould will begin to grow in an area with excessive moisture within 48 hours. A leak dried the same day is a plumbing bill. The same leak found a month later behind a finished wall is the cavity job Mold Inspection Canada prices at $5,000 to $15,000 a room. If the water came in as a leak or a flood, our water damage restoration page covers the drying.
In an Ottawa house the source shifts with the season. Winter brings condensation on cold surfaces, and Health Canada's range for indoor relative humidity is 30 to 50 percent, with a dehumidifier wherever moisture condenses. Bathrooms need their fan, which Health Canada says to keep running for at least 30 minutes after a shower or bath, plus prompt repairs to plumbing leaks and to cracked grout and caulking around the tub. Spring brings meltwater to the foundation. Pay for the source before the removal, or you pay for the removal twice.
How we quote mould removal.
We quote after seeing the space or your photos, and you get the figure before work starts. We size the area against Health Canada's chart first, and if it falls in the small band we will tell you it is a job you can do yourself. The full method, from tracing the water to containment and drying, is on our page about mould removal in Ottawa.
Budget for two costs outside our quote: repairing the leak or humidity that caused the growth, and independent clearance work on a large job. Hauling is inside it. Junk removal is our core service, so the bagged material, cut drywall and ruined carpet leave on our truck rather than waiting for a second company.
Whoever you hire, get the estimate in writing and into the contract. Ontario's consumer protection page says that if a written estimate is included in the contract, the final price cannot be more than 10 percent above it unless you agree to a new price and sign a change to the contract. Opening a wall can change a mould job's scope, and that signed change is what holds the new price.
Call or text (613) 852-4059 with photos of what you can see. Mould or mold, it is the same job, in Ottawa or Gatineau.
Two companies' published prices, side by side.
Each figure in this table is the named company's own published price for the job in that row, and both companies' pages were read on 2026-09-30. Neither is ours. The Health Canada and Government of Ontario pages this guide also cites were read on 2026-09-30, and linked at the foot of this page.
| Where the mould is | Mold Busters, Ottawa average | Mold Inspection Canada, 2026 national |
|---|---|---|
| Bathroom | $1,500 to $3,000 | $500 to $1,500 for mould on visible tile and grout, typically $1,000 |
| Basement | $1,800 to $6,000 | $500 to $4,000 for a small, dry basement, typically $1,500 |
| Attic | $1,500 to $5,000 | $1,000 to $4,000 after condensation, typically $2,000 |
| Crawl space | $1,800 to $5,000 | $500 to $10,000, typically $5,000 |
| Drywall or a wall | $1,500 to $4,000 | $1,000 to $20,000 per room, typically $7,500 |
| Air ducts and HVAC | $2,500 to $7,500 | $3,000 to $10,000, typically $6,500 |
| Whole house | $15,000 to $35,000 or more | $10,000 to $30,000, typically $20,000 |
| Inspection | Free to $500, with testing | $250 to $400 typical in Ottawa, Kanata and Gatineau |
Neither company that publishes prices for this area gives an Ontario figure. The closest are Mold Busters' Ottawa averages, $1,500 to $2,500 for minor mould on a small area and $2,500 to $7,500 for a larger area or several rooms, and Mold Inspection Canada's 2026 national figures, $500 to $1,500 for a bathroom and $10,000 to $30,000 for a whole house. Both pages were read on 2026-09-30. None of these is our price.
It depends on the area, where the mould is and whether it has gone behind the drywall. Published figures run from $500, the bottom of Mold Inspection Canada's national bathroom range, to $35,000 or more, the top of Mold Busters' Ottawa whole-house range. A patch under one square metre can cost you only a respirator, goggles, gloves and soap, since Health Canada says a small amount may be cleaned up using proper procedures and protective equipment.
Small visible jobs are not, and hidden ones are. Mold Inspection Canada prices mould on visible bathroom tile and grout at $500 to $1,500, and mould on the cavity side of a wall, with the drywall down, the insulation out and the framing dried for 5 to 14 days, at $5,000 to $15,000 for one room. Health Canada says that if the mould is underneath the paint, the drywall will need to be removed and replaced.
For large or hidden mould, yes. Health Canada's chart says a single patch larger than three square metres needs an expert assessment and cleanup, and recommends an assessment from one to three square metres. Not worth paying for: bleach, which Health Canada says not to use on mould, sealing or painting over growth instead of removing it, and an air test with no question behind it. Any remediation only lasts if the water behind the mould is fixed.
Usually not. Health Canada says that in most situations it does not recommend testing the air for mould, because a test cannot predict health effects and often says little about the cause. The exception is unexplained concerns after an inspection, especially with a history of flooding or leaks, where a professional may recommend testing to find hidden growth. Mold Inspection Canada puts a typical inspection in Ottawa at $250 to $400.
Only by taking away its water. Health Canada says that unless the cause of the moisture problem has been identified and solved, mould will reappear, and that mould will begin to grow in an area with excessive moisture within 48 hours. Remove the growth, dry the structure, fix the leak or the humidity, and keep indoor relative humidity between 30 and 50 percent.
Sometimes, depending on where the water came from. The Insurance Bureau of Canada lists the sudden and accidental escape of water from plumbing, heating, sprinkler and air conditioning systems among the insured perils of a home policy, and says gradual deterioration is not an insured peril. Your own policy's wording on mould decides, so call your insurer before any damaged material is removed.
Sources
- Health Canada, Guide to addressing moisture and mould indoors: the size chart, air testing, bleach, clearance studies and humidity read 2026-09-30
- Health Canada, Residential Indoor Air Quality Guideline: Moulds read 2026-09-30
- Government of Ontario, Your rights when signing or cancelling a contract: the 10 percent estimate rule read 2026-09-30
Want a price on your mould?
Call or text for an up-front quote. Same-day and next-day service across Ottawa and Gatineau.