Bathroom Mould Keeps Coming Back — Here's Why, and What Actually Works
Most people treat the mould, not the moisture. That's why it's always back within a few weeks.
Every bathroom has the ingredients mould needs: warmth, moisture and something for it to feed on (soap scum, skin cells, dust — mould isn't fussy). You can't remove all three permanently, which is exactly why mould keeps coming back for so many households no matter how hard they scrub it off. The scrubbing was never the fix on its own. Moisture control is.
The habit that actually makes the difference
If you do nothing else, do this: squeegee the shower walls and glass after every use. It takes about 30 seconds and it moves standing water off the surface and down the drain before it has a chance to sit in the grout and tile grooves where mould spores actually germinate. It sounds too simple to matter, but it's consistently the single most effective habit against recurring shower mould.
Pair that with running your exhaust fan during the shower and for 15–20 minutes afterward (or cracking a window if you don't have one), and you've dealt with the moisture side of the equation, which is most of the battle.
Removing mould that's already there
For everyday shower mould on sealant, grout or tile, a paste of bicarb and white vinegar (roughly two parts vinegar to one part bicarb, mixed to a thick paste) works well on silicone sealant specifically. Apply it with a damp cloth, work it into the affected area, leave it to sit for at least five minutes, then scrub and rinse. Bicarb's non-toxic, so it's a sensible option if you've got kids or pets around.
For more established mould on grout, you may need something stronger, and this is where a lot of people reach for bleach. That's fine on its own — just never combine it with anything else.
Never mix bleach with vinegar, or bleach with ammonia-based cleaners. Bleach and vinegar release chlorine gas; bleach and ammonia release chloramine gas. Both can cause serious respiratory irritation in an enclosed space like a bathroom, and it's genuinely not worth the risk chasing a cleaner shower. Use one product at a time, rinse the surface properly, and ventilate the room before switching to a different cleaner. We've written a full guide on cleaning products that should never be mixed if you want the full list.
When it's more than surface mould
Small patches of surface mould on tile and sealant are a normal maintenance job. If you're seeing mould spreading across a large area, coming back within days of cleaning it, showing up on walls or ceilings away from the shower itself, or you notice a musty smell that doesn't go away, that can point to a moisture problem behind the scenes — a leak, poor ventilation, or rising damp. That's worth getting looked at by a professional rather than treating with more scrubbing, because no amount of surface cleaning fixes a moisture source you can't see.
Daily habits that keep it from coming back
- Squeegee shower glass and walls after every use.
- Run the exhaust fan during and for 15–20 minutes after showering.
- Wipe down counters, faucets and the sink — five to ten minutes a day is genuinely enough to stop grime building up into something bigger.
- Leave the shower curtain or door open slightly after use so air can circulate and things dry out faster.
- Wash bath mats and shower curtains regularly — they hold moisture and are an easy spot for mildew to establish.
If bathroom mould's become a recurring fight in your house and you're just not winning it between the day job and everything else, it's exactly the kind of thing we sort as part of a regular cleaning visit — proper sanitising, not just a wipe-over.
Is it safe to mix bleach and vinegar to clean mould faster?
No — never mix bleach and vinegar. The combination releases chlorine gas, which can cause serious breathing irritation, especially in a small, enclosed bathroom. Use one product at a time and rinse the surface before switching to a different cleaner.
Why does mould keep coming back even though I scrub it every week?
Because scrubbing removes the mould you can see but doesn't address the moisture that let it grow back in the first place. Pair your cleaning routine with daily habits that reduce standing water and humidity — squeegeeing after showers and running the exhaust fan — and you should see it return far less often.
When should I call a professional instead of cleaning it myself?
If mould covers a large area, keeps returning within days, appears away from wet areas like ceilings or walls, or comes with a persistent musty smell, it's worth getting a professional to check for an underlying moisture or leak issue rather than continuing to treat the surface.
Our regular cleans include bathroom sanitising as standard — ask us about it if mould's a recurring issue in your place.
Book a CleanSources: EPA guidance on mould and moisture control; general bathroom hygiene and cleaning safety guidance on chemical combinations. Last checked July 2026. General information only, not a substitute for professional mould remediation advice on severe or structural mould issues.