TL;DR:
- Mould on carpet is a moisture problem first. Fix the water or it comes straight back.
- Surface growth after a recent, contained damp event often cleans up. Growth that reached the underlay or subfloor usually means the carpet comes up.
- The US EPA rule of thumb: dry water-damaged material within 24 to 48 hours, and hand over any patch bigger than about 10 square feet.
- We clean and extract after a minor household leak. We do not treat underlay or subfloor, and we do not take flood or sewage work.
- Bleach is the wrong first reach on carpet. Detergent or white vinegar is what Victoria health advice suggests, and it will not strip the colour.
You pull the bed away from the wall and there it is. A grey-green bloom across the carpet, and a smell you had been blaming on the dog. The first question is whether you can get mould out of carpet, or whether the lot goes in a skip.
The answer turns on how far the water went, not on how much mould you can see.
Can you get mould out of carpet?
Sometimes, and depth decides it, not the size of the patch. Surface growth after a recent, contained damp event, say a knocked-over bucket or a slow window leak, can usually be cleaned and dried back to normal.
Once mould has gone through the backing into the underlay or the subfloor, cleaning the top of the carpet only tidies up the half you can see.
That is not just a trade opinion. The US EPA puts it plainly: absorbent materials such as carpet may have to be thrown away if they become mouldy, because mould grows into porous material. NSW Health says it more gently, noting that carpet may need professional cleaning or replacement once it is contaminated.
Why does mould grow in carpet in the first place?
Moisture, and almost nothing else. The spores are already in your house, and they only become a problem when they find water and something to eat.
Here is the part that surprises people. The Carpet and Rug Institute points out that mould grows on the dirt in a carpet, not on the carpet fibre. A clean carpet in a damp room holds out far better than a dirty one beside it, which makes vacuuming less trivial than it sounds. The same body suggests vacuuming weekly and a deep clean every 12 to 18 months.
Melbourne's west gives mould a fair run at it. At the Bureau of Meteorology's Laverton station, the closest to Point Cook, mean 9am relative humidity climbs from 63% in January to 85% in June. Closed-up rooms hold that moisture longest, which is why a damp carpet smell usually arrives before anything visible.
Victoria's Better Health Channel is blunt about the fix. There is no practical way to get rid of all indoor mould, so the only real control is the moisture source.
How can you tell surface mould from a deeper problem?
Lift a corner and feel the underlay. That check tells you more than anything you can see from above.
Four things worth doing before you buy a product:
- Peel the carpet back at the skirting board and press the underlay with the back of your hand. Cool and dry is good news. Cool and damp is not.
- Look at the back of the carpet in that corner. Growth on the backing means it went through.
- Find the water: a blocked gutter, a leaking shower base, a split washing machine hose, condensation running off a window onto the carpet edge.
- Measure the patch. Under about 10 square feet, roughly a metre square, the EPA reckons most people can handle it themselves. Above that it is a job to hand over.
What to do in the first 48 hours
Speed beats technique. The EPA's guidance is that where wet material is dried within 24 to 48 hours, in most cases mould will not grow at all, and the Carpet and Rug Institute says to get water extracted and fans running within 24 hours.
- Stop the water. Nothing else matters until the source is off.
- Get air moving. Open windows, run a pedestal fan across the area, use a dehumidifier if you own one.
- Leave a large dry patch alone. Scrubbing or vacuuming dry mould flicks spores into the air for no gain.
- Cover up. For mould work at home, Better Health Channel suggests gloves, eye protection and a P1 or P2 mask.
- Do not paint over it. The EPA is clear the surface has to be cleaned and dried first, and paint buys a few weeks at most.
Can you clean mould out of carpet yourself?
Yes, if the patch is small, the underlay is dry and the leak is fixed. What matters is what you reach for.
Household detergent or white vinegar is enough in many cases, and that is where to start. NSW Health does list a diluted bleach solution, 250 mL in 4 litres of water, for stubborn cases. Sound on a tile or a painted wall. On carpet it is a gamble.
I have seen what the gamble costs. Supermarket stain removers with bleach-like ingredients have permanently lightened carpet on jobs I was called out to look at, and nothing brings that colour back. The Carpet and Rug Institute's advice on any spot treatment matches mine: pretest it somewhere out of sight, and never use laundry detergent, because the optical brighteners can dye the fibre.
Two habits to skip. Do not soak the area trying to flush the mould out, because over-wetting is the version of this I get called to most often. And do not tip deodorising powder over the top: it settles deep into the pile and holds dirt, so the smell fades while the damp carries on.
What a professional clean can and cannot do
This is the part most cleaning websites blur.
What we do is clean and extract. A proper hot-water extraction puts hot solution into the pile, agitates it, then pulls the soil and the water back out in the same pass. That takes away the soil mould feeds on and the moisture it needs, and steam-cleaned carpet is normally walk-on ready in 4 to 6 hours. Dry carpet cleaning is low-moisture, usually walk-on ready in 1 to 2 hours, which is often the better pick when the last thing a room needs is more water.
What we do not do is mould remediation. We do not treat the carpet underlay, the padding or the subfloor, and we do not take on flood, sewage or biohazard jobs. A minor household leak we can extract as part of a carpet clean. A flooded room belongs with a restoration outfit set up for it.
One job sticks with me. A homeowner washed a living room with a hired machine, poured in plenty of water and left the machine's vacuum switched off. The backing was soaked, the wooden subfloor under it had taken water too, and the room had turned sour. What I could do was the carpet: pull the water back out and treat the fibres. Carpet and smell both improved, in about an hour and a half. Left another week, that subfloor would have been someone else's job.
Not sure which side of that line you are on? Call us on (03) 4328 5637 and describe it. I would rather tell you the carpet needs replacing than take money for a clean that will not hold.
When does mouldy carpet need replacing?
When the growth reached the underlay or subfloor, when the water that caused it was not clean, or when it keeps returning after the room has been dried. Any one of those and you are replacing, not cleaning.
Better Health Channel's household rule is that mouldy items which cannot be cleaned should be disposed of, and that large areas of regrowth are the point to call a mould remediation professional.
Two markers from the carpet side. If the backing has gone brittle or started separating from the pile, cleaning will not bring it back, and carpet repair is not work we do. And if the room flooded from a drain or a toilet, the carpet goes. That is a contamination call, not a cleaning one.
Who is responsible for mould in a rental?
It depends on what caused it, and Consumer Affairs Victoria says as much. The law does not always assign responsibility, so the cause decides. A renter can be liable where their own behaviour contributed, such as never running the bathroom fan. The rental provider can be liable where a problem with the building caused the damp.
Tell the rental provider immediately, in writing, with photos and a date, because the paper trail is what any later argument turns on. Mould or damp tied to the building structure counts as an urgent repair once it makes the place unsafe to live in.
Keep the clean and the repair separate. Our end-of-lease carpet clean comes with a receipt for the property manager and a 7-day satisfaction guarantee, but no clean promises your bond back, and none of it touches the leak that grew the mould.
Frequently asked questions
Can mould be removed from carpet?
Sometimes. Surface growth after a recent, contained damp event can often be cleaned and dried. Once mould has gone through the backing into the underlay or subfloor, replacement is usually the honest answer.
Does carpet cleaning get rid of mould?
A professional clean removes the soil that mould feeds on and extracts the moisture it needs, which helps reduce the problem. It is not mould remediation: we do not treat carpet underlay, padding or subfloor, and we do not take on flood, sewage or biohazard work.
Should you use bleach on mouldy carpet?
Not as a first move. Victoria Better Health Channel says household detergent or white vinegar is enough in many cases, and bleach on carpet risks permanent colour loss. I have been called to carpet that supermarket stain removers lightened for good.
How do you get a mouldy smell out of carpet?
Fix the moisture first, get air moving, then have the carpet deep cleaned and extracted. Deodoriser only masks it while the damp carries on.
Is mouldy carpet an urgent repair in Victoria?
Consumer Affairs Victoria says mould or damp caused by or related to the building structure is an urgent repair when it makes the property unsafe or unsecure to live in. Tell the rental provider straight away, in writing, with photos and a date.
