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How to get rid of mould in a bathroom (and keep it from coming back)

26/05/2026
Read Time 11 mins
Written by Ryan Evans
How to get rid of mould in a bathroom (and keep it from coming back)

Black patches along the silicone around the bath. Spots creeping across the grout. A musty smell that hangs around after every shower. Bathroom mould is one of the most common household problems in the UK, and one of the most frustrating to deal with because it keeps returning if you only treat the surface.

This guide covers what actually causes it, how to remove it from the surfaces it grows on, and what to change to prevent it from coming back.

How to get rid of bathroom mould

Before you start, open the window, get some air moving, and put on rubber gloves, a proper mask (FFP3 or better) and eye protection. Mould spores become airborne the moment you disturb the growth, and you don't want to breathe them in or catch them in your eyes.

What you'll need

      Rubber gloves, a mask, and eye protection.

      A stiff brush. An old toothbrush works well on grout lines.

      Microfibre cloths and a bin bag for contaminated cloths.

      A spray bottle.

      One of the cleaning solutions below.

Method one: white vinegar

Good for light to moderate surface mould on tiles, glass, grout and sealant. Vinegar is acidic enough to kill around 82% of mould species, and it doesn't leave the toxic residue that bleach does.

1.     Pour undiluted white vinegar into a spray bottle.

2.     Spray directly onto the mould. Don't dilute it. Full strength works best.

3.     Leave for an hour.

4.     Scrub with a brush, focusing on grout lines and corners.

5.     Wipe clean with a damp cloth.

6.     Dry the surface thoroughly.

Method two: baking soda paste

Best for grout lines and textured surfaces, where vinegar runs off before it can work.

1.     Mix two tablespoons of baking soda with enough water to form a paste.

2.     Apply directly to the affected grout.

3.     Leave for 10 minutes.

4.     Scrub with an old toothbrush.

5.     Rinse and dry.

A follow-up vinegar spray catches anything the baking soda missed. Don't mix them into a single solution, as they neutralise each other and lose most of their cleaning power.

Method three: dedicated mould remover

For stubborn black mould or larger affected areas, a commercial mould and mildew spray does the job faster. UK supermarkets and DIY shops stock HG, Cillit Bang, Dettol and Astonish mould sprays, among others. Follow the product instructions: some need rinsing after a set time; others are designed to dry onto the surface.

When to use bleach (and when to avoid it)

Bleach works well on non-porous surfaces such as ceramic tiles, shower trays, baths, and glass. It's less effective on grout, silicone, and painted plaster because it kills the surface growth without penetrating deeply enough to reach the roots. Use a solution of one part bleach to four parts water.

One safety point that matters: Mixing bleach with vinegar releases chlorine gas; mixing it with ammonia releases chloramine gas. Both can cause serious respiratory injury.

Cleaning mould off specific surfaces

Different surfaces call for different approaches. The methods above are the basis. Below is how to adapt them to what you're actually cleaning.

Tiles and grout

Start with vinegar. If that doesn't shift it, move to a baking soda paste worked in with an old toothbrush. For grout that's stained beyond cleaning, a grout pen covers marks that won't come out. If the grout is crumbling or pulling away from the tile, the better option is to rake it out and apply new grout with a mould-resistant additive.

Silicone sealant

Mould that's gone deep into old silicone is the hardest to remove. Once it's embedded in the silicone itself, surface cleaning won't bring it back. The only permanent answer is to strip the old sealant out and reapply fresh. A silicone removal tool, a caulk gun, and a tube of mould-resistant bathroom sealant will cost under £20 combined, and the job takes an afternoon.

If you'd rather not scrape the sealant out yourself, a toilet paper trick works surprisingly well on mild cases. Roll a few sheets into a sausage, soak it in bleach, lay it along the affected sealant, and leave it for 12 hours. Remove, rinse, and repeat if the mould is deep.

Painted walls and ceilings

Wash down with a vinegar spray or a dilute bleach solution. Once fully dry, apply a coat of anti-mould paint. Most UK DIY shops stock specialist bathroom paints that contain a fungicide. Anti-mould paint doesn't replace proper ventilation, though it does buy you time between deep cleans.

If the paint is bubbling, flaking or peeling away from the plaster, there's water damage underneath. A coat of paint over that won't fix the problem for more than a few weeks. The damaged plaster needs cutting out, drying and replacing first.

Shower screens and glass

Vinegar spray, wipe with a microfibre cloth, dry. For prevention going forward, a squeegee after every shower takes fifteen seconds and stops limescale, soap scum and mould from building up in the first place. If the screen is past its best, a replacement is a worthwhile upgrade. Browse our range of shower enclosures.

Shower curtains, bathmats and fabric

Most modern shower curtains can be machine-washed at 60°C with standard detergent. A handful of white vinegar in the drum helps. Heavily mouldy curtains often aren't worth rescuing. New ones cost a few pounds and start clean.

Bathmats follow the same rule. Wash hot, dry fully before putting them back, and hang them up after use rather than leaving them on the floor. Wet fabric on a cold tile is a reliable way to foster mould growth.

Behind radiators, towel rails and fixtures

Mould loves the gap behind a heated towel rail where air doesn't circulate. If you can reach the area with an extended duster or a long brush, clean it the same way you'd clean a wall. If the mould is heavy and you can't reach it properly, the rail or radiator may need to come off the wall to be dealt with.

How to stop bathroom mould coming back

This is the part most people skip, and it's why mould keeps returning. Cleaning the surface does nothing if the conditions that created it are still in place.

Sort the ventilation first

An extractor fan that actually works is the single most useful thing in a bathroom. If you've got one, check it's pulling air properly. Hold a sheet of toilet paper near the vent with the fan on. If it doesn't stick, the fan needs servicing or replacing.

A stronger model with a humidistat is the upgrade worth paying for. A humidistat fan turns itself on when humidity rises above a set level, so it runs whether you remember to switch it on or not. If a fan isn't practical in your bathroom, open the window during and after every shower for at least ten minutes.

Wipe down after every use

A squeegee for the shower screen. A microfibre cloth for the tiles around the bath and the window. Drying out the wet zones after every use prevents the moisture from mould growing. Sounds like a faff; takes under a minute once it's a habit.

Use a dehumidifier in hard cases

Worth considering in flats, loft conversions and internal bathrooms with limited ventilation. A small compressor dehumidifier pulls moisture directly out of the air. Some models are designed for bathrooms specifically and sit happily in the corner.

Anti-mould paint when redecorating

Standard emulsion absorbs water vapour, which feeds mould. Anti-mould paint doesn't. If you're repainting the bathroom anyway, the upgrade costs a few pounds per tin and lasts for years.

Plants that actually reduce humidity

A short list of houseplants genuinely helps by absorbing moisture from the air and pulling mould spores out of the air passing by their leaves:

      Peace lily: Low light, tolerates neglect, good for bathrooms with small or no windows. Worth noting that peace lilies are toxic to cats and dogs if chewed.

      English ivy: Absorbs airborne mould spores. Works well in a hanging planter where it has room to trail.

      Snake plant: Nearly impossible to kill. Handles humidity without complaint.

      Boston fern. Needs more light, but excellent at pulling moisture from the air.

      Tillandsia (air plants): Absorb moisture directly through their leaves. Brilliant if you have a bright bathroom window.

Clean regularly

A proper bathroom clean once a week keeps mould from getting a foothold. Pay particular attention to corners, the sealant around the bath, and the grout between tiles. Most mould problems start small and spread because they go unnoticed for weeks.

What causes mould in a bathroom?

Mould spores are in the air of every home, outdoors and in. They only become visible growth when three things line up: moisture, a warm surface they can settle on, and enough time in those conditions to colonise. Bathrooms provide all three, which is why they're the most common mould hotspot in UK homes.

The main culprit is condensation. Hot water from a shower creates steam. When that warm, wet air meets a colder surface (a tile, an external wall, a window), the moisture condenses into water and settles there. If the room doesn't have enough ventilation to clear it, the moisture sits long enough for spores to take hold. UK Government guidance identifies condensation as the leading cause of damp and mould in British homes.

Other common causes:

      Leaking taps, pipes or toilet cisterns: Slow, hidden leaks keep surfaces wet for weeks without being noticed.

      Damaged silicone or grout: Once the seal around the bath or shower cracks, water gets behind it and mould grows where you can't easily reach.

      Poor or missing ventilation: No extractor fan, a fan that's stopped working, or a window that's never opened.

      Drying laundry indoors: A typical load releases around two litres of water into the air as it dries.

If you've just moved into the house or the mould has appeared suddenly, check for a new leak before anything else. Removing the surface growth is pointless if water is still getting in behind the scenes.

Is bathroom mould actually dangerous?

Yes, and it's worth taking seriously. The NHS states that mould and damp can cause allergies, asthma attacks and respiratory infections. People most at risk include babies and young children, older adults, anyone with asthma or a skin condition, and people with weakened immune systems. Asthma + Lung UK reports that 43% of people with asthma say mould triggers their symptoms.

If the mould covers more than around half a square metre, or if it's growing through the wall rather than sitting on the surface, that's the point to call in a professional rather than tackle it yourself. It's estimated that between 120,000 and 160,000 social homes in England have “notable” damp and mould problems, so if you're renting, you're not alone in dealing with it.

Common questions about bathroom mould

What kills mould in a bathroom permanently?

Nothing kills mould permanently because spores are always present in the air. What you can do is remove the visible growth, fix the underlying moisture problem, and keep humidity low enough that spores can't colonise. Ventilation, surface drying and regular cleaning do more long-term work than any single cleaning product.

Does vinegar actually kill mould?

Yes, against the most common household mould species. White vinegar at full strength kills around 82% of mould types, including many found in UK bathrooms. It's less effective against some toxigenic moulds, which is the point at which a dedicated commercial product or a bleach solution becomes the better choice.

Does bleach kill mould?

On non-porous surfaces (tiles, shower trays, glass), yes. On porous surfaces (grout, silicone, painted plaster), it kills surface growth while allowing roots to regrow. Vinegar or a dedicated mould spray is a better choice for porous materials.

What is the difference between mould and mildew?

Mildew is the earlier, surface-level stage. Powdery or patchy, white, grey or yellowish. Easy to wipe off. Mould is a later, denser stage. Usually black, green or brown, and it has penetrated the material it's growing on. Mildew becomes mould if left alone for long enough.

Why does mould keep coming back in my bathroom?

Almost always because the underlying cause hasn't been addressed, check for a hidden leak, poor ventilation, cold spots on the walls (common on external walls and above old bay windows) or damaged sealant. Surface cleaning alone won't solve a moisture problem.

How long does it take for mould to grow in a bathroom?

Given the right conditions, it can take as little as 24 to 48 hours. That's why drying the bathroom out after use matters. Leave a wet bathroom overnight a few times, and a new colony can establish itself behind the sealant before you notice anything.

Can I paint over black mould?

Not directly. Paint over live mould flakes off within weeks because the fungal growth underneath continues. Kill and clean the mould first, let the surface dry fully, then apply an anti-mould paint.

What's the best way to prevent mould on a bathroom ceiling?

Ventilation during and after every shower, an extractor fan sited near the shower rather than over by the door, and a coat of anti-mould paint on the ceiling. If condensation collects heavily on the ceiling, insulation in the loft space above helps by keeping the ceiling surface warmer and reducing the temperature gap that causes condensation in the first place.

When to call a professional

Tackle the cleaning yourself if there's surface mould on tiles, grout, silicone, or paint, and it covers less than around half a square metre. Call in a damp specialist if:

  • The mould keeps returning within weeks of cleaning.
  • It's growing through the wall rather than sitting on the surface.
  • You can see water damage (bulging plaster, flaking paint, wet patches) behind the mould.
  • You've got a persistent leak you can't find.
  • You're renting. Your landlord or letting agent has a legal obligation to address damp and mould under the Homes (Fitness for Human Habitation) Act 2018. Shelter has practical guidance on how to raise it with your landlord.

Mould that has penetrated plasterboard or structural timber is beyond a DIY fix. It needs to be removed at the source, and the damaged material replaced.

When the bathroom needs more than a clean

Most mould problems trace back to three things: ventilation, moisture and ageing fixtures. A weekly wipe handles the moisture. A working extractor fan handles the ventilation. The third, ageing fixtures, is where a bathroom eventually stops responding to cleaning. If that sounds familiar, our team at the Birmingham showroom can help you plan a replacement that holds up better to damp. Mould-resistant materials, properly fitted ventilation, and furniture built to last. Have a look at our bathroom suites, shower enclosures and bathroom furniture ranges, or book a showroom visit to talk through a refit with someone who's been fitting bathrooms for forty years.