For small patches of mould on hard surfaces, start with mild detergent or vinegar; that’s what NSW Health recommends for routine clean-up, with diluted bleach as the fallback for stubborn marks. Bleach is better at whitening the stain than at reaching growth in porous material, and neither product does anything about the moisture causing the mould. Never mix the two.
What NSW Health recommends
The NSW Health mould fact sheet sets out a simple order:
- For routine clean-up of mouldy surfaces, use mild detergent, or vinegar diluted in water (it specifies 4 parts vinegar to 1 part water).
- If the mould isn’t readily removed and the item can’t be thrown out, use a diluted bleach solution (250 mL of bleach in 4 litres of water).
- With bleach, wear PVC or rubber gloves, safety glasses and safety shoes, and keep the area well ventilated.
- Dry the surface completely afterwards.
- Absorbent materials such as carpet may need professional cleaning or replacing.
It also notes that mould is likely to return unless you treat the cause, which is the part most people skip.
How the two compare
| White vinegar | Household bleach | |
|---|---|---|
| Role in NSW Health’s advice | Routine clean-up | Fallback when mould isn’t readily removed |
| Hard, non-porous surfaces (tiles, glass, sealed grout) | Works with contact time and scrubbing | Works, and whitens staining quickly |
| Porous materials (plasterboard, timber, unsealed grout, silicone) | Doesn’t reach growth below the surface | Often lightens the mark while growth remains |
| Handling | Mild smell | Needs gloves, eye protection and ventilation |
| Effect on fittings | Gentle with occasional use | Can be harsh on tapware and sealant with repeated use |
| Fixes the moisture | No | No |
The practical difference: bleach makes the patch look gone, which is why it’s popular and why mould on a painted ceiling often reappears in the same spot. The growth in the paint film or plasterboard was never reached, and the damp that fed it is still there.
Never mix bleach with vinegar or other cleaners
Health Canada warns never to mix any cleaning product with household bleach, because mixing it with acidic cleaners such as vinegar, or with ammonia products such as some glass cleaners, can create toxic gases. Use one product at a time, rinse between them, and keep the room ventilated. If anyone feels unwell after exposure, call the Poisons Information Centre or seek medical help.
Bathroom ceilings and grout
For tiles and sealed grout, either works; vinegar is the easier choice for regular maintenance. Painted bathroom ceilings are where both products disappoint. Repeated bleach can wear the paint film, and neither touches the real cause, which is usually an exhaust fan that’s undersized, not vented outside, or not run long enough. If ceiling mould keeps returning after cleaning, the fan and airflow need fixing, which is what bathroom and ceiling mould removal addresses. Repainting with an anti-mould product only helps after that; see the anti-mould paint guide.
How to clean a small patch safely
- Ventilate the room before you start and keep it ventilated.
- Wear gloves, and eye protection if using bleach.
- Try detergent or diluted vinegar first. Apply, leave it for a few minutes, then scrub.
- Move to diluted bleach only if the mark won’t shift, and never on the same surface without rinsing in between.
- Dry the surface completely.
- Fix whatever made it damp: run the exhaust fan longer, open a window, wipe down wet tiles, pull furniture off a cold wall.
When neither is the right tool
Household cleaning is the wrong category of fix when:
- The mould covers more than a small patch, or appears in several places
- It’s growing into a porous material: plasterboard, soft or bubbling paint, timber, carpet or insulation
- It returns after cleaning
- There’s a musty smell but nothing visible, often a sign of the subfloor or roof void
- It followed a leak, storm or flood, where hidden wet material is likely
- It’s a rental and you need documented treatment rather than a wipe-down
The mould removal vs remediation guide explains what professional treatment does differently: finding the moisture source, containing the area, removing affected porous material rather than wiping it, and confirming it’s dry afterwards. If mould has already come back after a clean, the why mould came back guide covers the usual reasons.
Not sure which side of the line you’re on? Send a couple of photos and your suburb through the quote form. Your enquiry goes to an independent local contractor, who quotes in their own name.
Frequently asked questions
Does vinegar kill mould better than bleach?
For small patches on hard surfaces, vinegar is a reasonable first choice and is what NSW Health suggests for routine clean-up. Bleach is better at removing the visible stain. Neither reliably reaches growth inside porous materials, and neither fixes the moisture.
Can I mix bleach and vinegar to make it stronger?
No. Mixing bleach with an acid such as vinegar can release toxic gas. Use one product at a time, rinse between them, and keep the room ventilated.
Why does mould keep coming back after I clean it with bleach?
Bleach whitens the surface without reaching growth in the paint film or plasterboard behind it, and it does nothing about the condensation, leak or poor ventilation feeding the mould. Until that is fixed, cleaning is temporary.
Do I need gloves or a mask?
NSW Health recommends gloves, safety glasses and safety shoes when using bleach, and good ventilation. Gloves are sensible with any cleaner. If the area is large enough that you’re worried about breathing it in, that’s a sign it’s beyond a DIY clean.
Is mildew cleaned the same way?
Yes. Light surface growth on fabric, shower curtains or sills comes off with detergent or vinegar. See mould vs mildew for how to tell when it’s more than surface growth.