Prep first
Before you start
- Fix the water source first and dry everything completely.
- Wear gloves, goggles without vents, and an N-95 respirator so you don't breathe in or touch spores.
- Brush loose mold off outdoors if possible, so spores don't scatter in the house.
- Scrub mold off hard surfaces with detergent and water, and dry completely.
Bathtub mold comes back wherever the tub stays wet, so fixing the water problem has to come before any scrubbing. On a hard tub surface the growth usually lifts with a mild wash, a rinse and a fully dry tub. If your tub is acrylic and already dull or scratched, that needs manufacturer repair, so keep the pressure light the whole way through.
Cleaning bathtub mold with vinegar is a sensible try on the flat tub surface. Tub caulk and grout hold moisture in their lines, so they need more time and a little more patience. If black mold keeps coming back after a vinegar wipe, a mold remover made for bathtubs is the thing to reach for.
Before you start
What bathtubs can take
Safe to use1
- Water
Use with care4
- Soaking
- Chlorine bleach
- Acids (vinegar, lemon)
- Scrubbing and abrasives
Avoid1
- Solvents (alcohol, spot removers)
7 items
What you'll need
Tap an item to get it on Amazon, or tick what you already have.
- Mild liquid dish soapThe first scrub for hard tub surfaces, mixed into warm water. (opens Amazon)
- White vinegarFor the mold left after the soap scrub. Use white only. (opens Amazon)
- Soft spongeThey keep the scrub gentle on the tub surface. (opens Amazon)
- Soft brush (opens Amazon)
- Gloves, goggles without vents and an N-95 respiratorThey keep spores off your skin and out of your lungs. (opens Amazon)
- Clean towelsTo dry the tub completely before you use it again.
- Bathroom fan or a windowKeeps the room ventilated while you clean and dry. (opens Amazon)
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6 steps
Step by step
Step 1 of 6
Fix the water problem first
Find the leak or other water problem and fix it before you clean, because mold needs water or moisture to grow. Plumbing leaks should be dealt with as soon as possible. Dry any items in the room completely as you go.
Step 2 of 6
Gear up and ventilate the room
Put on gloves, goggles without vents and an N-95 respirator so you don't breathe in or touch the spores. Run the bathroom fan or open a window before you start, and keep the room ventilated while you work.
Tip. If the mold is loose, brush it off outdoors if you can, so the spores don't scatter through the house.
Step 3 of 6
Scrub with mild detergent and water
Mix mild dish soap into warm water and scrub the mold off the hard tub surface with a soft sponge. Rinse the sponge often so you aren't spreading spores back onto clean areas. Work from the top of the tub down so runoff doesn't cross the parts you've already cleaned.
Careful. Don't use steel wool or wire brushes on cast iron.
Step 4 of 6
Apply white vinegar to what remains
Spray white vinegar onto any mold still there after the soap scrub, then brush it gently with a soft brush while the surface is still wet. The vinegar is for stubborn spots, so you don't need to flood the whole tub with it.
Careful. Use white vinegar only; colored vinegar can leave a stain.
Step 5 of 6
Rinse off every trace of cleaner
Rinse the whole tub and nearby surfaces with clean water until no soap or vinegar film is left. Overspray can land on the walls, tile and fixtures, so rinse those too.
Careful. Don't let cleaners soak on the surface; rinse them off right away.
Step 6 of 624 to 48 hours
Dry the tub completely
Dry the tub with clean towels and run the fan until everything is dry. Wet areas dried within 24 to 48 hours usually won't grow mold, so check the corners and joints before you use the tub again.
Tip. Keep the fan running or the window open for part of the drying time.
If you'd rather buy than mix
Best products for mold on bathtubs
Pick a cleaner labeled for mold or mildew on hard surfaces rather than a general all-purpose spray. Check it against your tub material before you use it.
MOLD ARMOR Rapid Clean Remediation
How we picked these: each product is made for this type of stain, its maker doesn't warn against using it on bathtubs, and its directions fit the steps above.
Finished the steps? How does it look?
Nice work. Let it dry completely and check it again in good light. Here is what done looks like:
How to tell it's really gone →A faint mark usually needs one more round, not a stronger product.
See what to do for what you're seeing →Heavy buildup usually takes more than one round.
Heavy or long-standing buildup →When to call a professional →How to tell it's working
When the tub is right, the surface looks clean in daylight and no fuzzy or dark specks remain once it's fully dry. A faint mark that stays after drying means the stain has set in, and the stronger options below are the next step.
What changes for yours
Adjust for your bathtubs
Tub caulk and caulking
Caulk sits where water collects along the tub edge, so mold often shows up there. Use the same soap scrub first, then the vinegar on anything left, and keep the pressure light so you don't dig into the sealant.
If the mold is still dark after the caulk has dried fully, the sealant may be stained all the way through. At that point it's better to cut out the old caulk and recaulk the joint once the area is clean and dry.
Bathtub grout
Grout is porous, so mold can sit deep in the lines. Vinegar isn't safe on cement grout, so use only the mild dish soap and warm water with a soft brush there.
Scrub the lines, rinse them well and let them dry completely before you judge the result. If they're still dark after several rounds, the grout may need replacing rather than more scrubbing, since porous material can keep mold in its crevices.
Heavy or long-standing buildup
Old mold that has sat on the tub for weeks is harder to lift, because it has had time to work into the surface and the caulk or grout around it. Start with the steps above and give the spot a second, slower pass before you reach for anything stronger.
If a dark spot is still there after it has dried, try 3% hydrogen peroxide, the mild antiseptic sold in drugstores, on the spot. Test it on a small hidden area first, don't use the stronger solution sold for bleaching hair, and rinse it off well with clean water afterward.
Be realistic about what a tub can do, because porous grout and caulk can keep a mark that cleaning doesn't fully remove. If the mark is still there after the stronger pass, the answer may be recaulking or regrouting rather than more scrubbing.
Vinegar, baking soda, peroxide and more
Do home remedies work on mold on bathtubs?
Many home remedies for mold get passed around, but some can damage a tub and others do nothing for mold. Only mild dish soap, warm water and white vinegar are worth using, and the rest can be skipped.
Works2Helps1Skip2Avoid1
What makes it worse
Mistakes to avoid
Don't mix vinegar and chlorine bleach.
Chlorine bleach should never be combined with vinegar or lemon juice. It should also never be mixed with ammonia or any cleaner that contains it, because toxic fumes could be produced.
Don't rely on bleach as a routine fix.
Chlorine bleach isn't a good everyday mold cleaner on a tub. If you do use one, ventilate and exhaust the air outdoors, and never use full-strength bleach on an airjet acrylic bath.
Don't scrub with abrasives alone.
Never use abrasive cleaners without water, and skip abrasive cleansers entirely on acrylic. Strong abrasive cleaners also scratch and dull vitreous china, so the soft sponge in the steps is the right tool.
Don't paint or caulk over mold.
Paint applied over mold is likely to peel, so clean and dry the surface before you touch it with paint or caulk. Wait until the whole area is fully dry before any new sealant goes down.
Don't use aerosols or solvents on acrylic.
Avoid aerosol cleaning products on acrylic, and don't use solvents on acrylic, cast iron or vitreous china. Both can damage the finish.
Troubleshooting
If the stain is still there
Pick what you're seeing:
Mold keeps coming back within days
The bathroom is staying damp. Run the fan longer, open a window and wipe the tub dry after each use.
The caulk stays black after scrubbing
The mold has likely worked into the caulk. Remove it, clean and dry the joint completely, and then recaulk.
The acrylic looks dull after cleaning
Stop using whatever product or pad caused it. Dull or scratched acrylic needs repair from the manufacturer.
A stubborn stain stays on a cast iron tub
Kallista allows abrasive cleaners sparingly on cast iron for stubborn stains, always with water. Rinse thoroughly afterward.
When to call a professional
Call an experienced professional if the mold covers more than about 10 square feet, or if it came from sewage or contaminated water. Those jobs need full remediation with proper protection and cleanup, which is more than a tub scrub can handle.
Questions
Is black mold in a bathtub different from regular mold?
The same steps apply, so start with the water fix and the soap scrub. If the black stain doesn't lift after drying, the set-in treatment above is the next thing to try.
Do I need a special mold cleaner for the bathtub?
Usually not. The mild dish soap and warm water handle most tub mold, and the vinegar covers what's left. A commercial cleaner is an option if you'd rather use one, as long as it's safe for your tub material.
Will the mold stain stay on my bathtub after cleaning?
Often the mark lifts with the scrub and the drying. A stain that stays after a full dry may be set in, so try the hydrogen peroxide treatment before deciding it's permanent.
How do I know what my tub is made of?
Check the paperwork that came with the tub or ask the installer. If you still don't know, use only mild dish soap and warm water with a soft sponge, and skip the vinegar and any stronger products.
When should I call a professional for tub mold?
Call a professional if the mold covers more than about 10 square feet, or if it came from sewage or contaminated water. Those cases need full remediation, not a tub scrub.
What if my acrylic tub is already scratched or dull?
Dull or scratched acrylic needs repair from the manufacturer, so contact its customer service first. Keep to the mild steps here in the meantime.
Mold on other materials
Other stains on bathtubs
Start from the bigger picture
How we know this
Every method, amount and warning here comes from university extension services, industry bodies and product makers. We read them, check every step for unsafe combinations and changed amounts, and write it up so you can follow it.