Prep first
Before you start
- If the bleach mixture touches your skin, wash it off quickly.
- Rinse thoroughly between products so nothing is left on the surface.
- If the stain doesn't respond after one full round, it may be damage rather than dirt.
Black stains in a shower are most often mildew, though soot, manganese from well water, tarnish and greasy residue can look almost identical. Chlorine bleach needs care in a shower, and if the mixture touches your skin, wash it off quickly. Some black marks are damage rather than dirt, so a mark that doesn't respond may not come out fully.
Black spots in shower corners and black stains on the shower floor usually respond to a mold and mildew remover, once you've checked the surface. Shower glass doors need a gentler touch, so keep a scouring cleanser away from them. If the black marks keep coming back within a few days, call a professional.
Before you start
What showers & glass doors 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
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- Household liquid bleachThe mildew treatment, mixed at one part to three parts water. (opens Amazon)
- BucketFor mixing only the amount of solution you need. (opens Amazon)
- Protective eyewearKeeps splashes out of your eyes while you mix and scrub.
- Protective clothing and waterproof glovesKeeps the bleach solution off your skin. (opens Amazon)
- Ventilated maskRecommended while you mix and scrub.
- Soft scrub brushLifts the mildew without scratching the surface. (opens Amazon)
- Soft clothFor drying the surface after the final rinse. (opens Amazon)
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5 steps
Step by step
Step 1 of 5
Check the stain before you wet it
Brush or vacuum any dry growth off before the surface gets wet, and do it outdoors if you can. Then look closely at the spot to confirm it's mildew and not a metal or soot stain that needs a different approach.
Careful. Try any cleaner on a hidden spot before the full area.
Step 2 of 5
Put on protective gear
Put on protective eyewear, protective clothing and waterproof gloves before you open the bleach. A ventilated mask is also recommended while you work.
Step 3 of 5
Mix the bleach solution
Mix one part liquid bleach with three parts water in a clean bucket. Make only as much as you need for the area in front of you.
Careful. Never add detergents or ammonia to the bleach solution, and never mix bleach with acids such as vinegar.
Step 4 of 510 minutes
Scrub the mildew and let it sit
Apply the solution to the mildewed area and scrub it. Leave it on the surface for 10 minutes before you move on to the rinse.
Tip. Work in small sections so the scrubbing stays even across the whole shower.
Careful. Rinse any overspray off nearby surfaces right away.
Step 5 of 5
Rinse well and let it dry
Rinse thoroughly with water, then let the surface dry completely. Check the corners and edges for any dark spots you missed.
Tip. If a few dark spots remain, the set-in section below explains the next round.
If you'd rather buy than mix
Best products for black stains on showers & glass doors
Use plain household liquid bleach for the solution, and skip any product that mixes bleach with other cleaners.
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 showers & glass doors, 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.
Heavy buildup usually takes more than one round.
Heavy or long-standing buildup →When to call a professional →How to tell it's working
Once the surface has dried, the black should be gone rather than just lighter, and the area should look even. Check the corners and edges too, since they're easy to miss.
What changes for yours
Adjust for your showers & glass doors
Shower floor
The same bleach method works on the floor, so the steps above stay as they are. If the floor is an acrylic pan, keep the scrubbing gentle with a soft brush.
If the black is mainly in the grout lines, the Grout guide goes deeper on that surface. Work the floor in small sections so you can rinse each one before you start the next.
Shower glass doors
Black marks on shower glass are often the same mildew or soot, but glass has its own rules, so start with the Glass, Windows & Mirrors guide. That guide covers the glass itself before you choose a treatment.
If the black is on the frame or seal rather than the glass, the steps above still apply to that mildew. Keep the bleach off any trim until you've checked its finish.
Heavy or long-standing buildup
If the black is still there after one pass, it's probably ingrained rather than fresh. Some black marks are damage rather than dirt, and those won't lift however hard you work.
Repeat the bleach solution on the same spot, one part liquid bleach to three parts water, and leave it for 10 minutes before you rinse thoroughly. Let it dry, then look again, because a wet surface hides what's left.
If the surface looks dull or scratched after the black is gone, that's damage that cleaning won't fix. Stop after a second round if nothing changes, and accept that a faint mark may stay.
Vinegar, baking soda, peroxide and more
Do home remedies work on black stains on showers & glass doors?
The bleach solution is what handles mildew, so none of the other remedies can stand in for it. Some are unsafe on common shower materials or shouldn't be mixed with bleach, so skip them.
Skip4Avoid2
What makes it worse
Mistakes to avoid
Don't paint over mildew
Paint over mildew and it keeps growing underneath the coating, so the black comes back through. Clean the area first and only decide on paint once it's fully clean and dry.
Don't use bleach on a stain you haven't identified
Chlorine bleach can intensify manganese or iron stains, which can look similar to mildew. If the stain could come from well water or metal, check the cause before you reach for the bleach.
Don't scrub acrylic with abrasives or solvents
Abrasive cleansers and solvents damage the bath surface, so use a soft brush and water instead. Aerosol cleaning products are also a poor choice on acrylic.
Don't let bleach reach the faucet finish
Don't let bleach, ammonia or acid cleaners touch PVD faucet finishes, because they can damage them. Keep the solution off the fixtures and wipe any splashes off them straight away.
When to call a professional
For dull or scratched acrylic, contact the manufacturer's customer service for repairs. If the stain stays after repeated rounds and the surface looks damaged, a professional cleaner can assess it before you try anything stronger.
Questions
How do you clean black spots in a shower?
Brush off any dry growth, then scrub with one part bleach to three parts water and let it sit for 10 minutes. Rinse thoroughly and let the surface dry. Test a hidden spot first, and stop if the stain turns out to be a metal stain.
Is black in a shower always mold?
No, it's often mildew, but it can also be soot, manganese from well water, tarnish or greasy residue. The steps here are built for mildew, so check the cause if the stain doesn't respond.
Can I use this on shower floor grout?
The bleach solution works on mildew wherever it sits in the shower, grout included, as long as the black is mildew. For grout lines in particular, the Grout guide covers that surface in more detail.
Should I leave the bleach on longer for a tough stain?
No, let it sit the full 10 minutes and no longer. For a tough stain, repeat the bleach round on the same spot and check again once it's dry.
Can I use black shower glass cleaning steps on the glass door?
Start with the Glass, Windows & Mirrors guide, since glass has its own rules. If the black is mildew on the frame or seal, the steps here still apply to that area.
Can I use vinegar or dish soap instead of bleach?
No, the bleach solution is the treatment for this mildew. Vinegar isn't safe on cement grout or natural stone, and dish soap isn't a shower choice here.
Black Stains on other materials
Other stains on showers & glass doors
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.