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Fix mildew on a shower

We'll confirm it is surface mildew, clean it with vinegar or bleach, improve ventilation, and tell you when to call a pro.

Troubleshooting · Home maintenance
15–30 min
What you'll need
  • White vinegar
  • Spray bottle
  • Stiff brush or old toothbrush
  • Bleach (optional, if vinegar fails)
  • Rubber gloves and eye protection (if using bleach)
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Steps

Goal: Confirm surface mildew, clean it, improve ventilation, and prevent recurrence.

  • Inspect the shower. Surface mildew is pink, gray, or small black spots that wipe off. Black mold is thick, slimy, dark, and covers large areas.
  • Good: Surface mildew—proceed to Confirm ventilation.
  • Bad: Black mold or area >10 sq ft—see When to get help.

Confirm ventilation

Goal: Ventilate the bathroom before cleaning. Bleach fumes require strong ventilation.

  • Turn on the exhaust fan or open a window. If the fan does not run, check that it is on and the duct is clear.
  • Good: Air is moving. Proceed to Clean with vinegar.
  • Bad: No ventilation—open a window or delay until you can ventilate.

Clean with vinegar

Goal: Remove surface mildew with vinegar. Safe and effective for most shower mildew.

  • Mix white vinegar (1:1 with water) in a spray bottle. Spray walls, grout, caulk, and corners.

  • Let sit 15 minutes. Scrub with a stiff brush or old toothbrush.

  • Good: Mildew disappears or lightens. Proceed to Rinse and dry.

  • Bad: Mildew remains—try Clean with bleach.

Clean with bleach

Goal: Use diluted bleach when vinegar fails. Never mix bleach with vinegar.

  • Rinse vinegar off completely first. Mix 1/2 cup household bleach per gallon of water. Spray or apply to affected areas. Let sit 5–10 minutes. Scrub with a brush. Wear gloves and eye protection.

  • Good: Mildew is gone. Proceed to Rinse and dry.

  • Bad: Mildew is still embedded—see Replace grout or caulk.

Rinse and dry

Goal: Remove cleaner residue and reduce moisture so mildew does not return quickly.

  • Rinse all surfaces with clean water. Use a squeegee or towel to remove standing water. Run the exhaust fan 30 minutes. Wipe down the shower after each use. You should see less moisture buildup.

Replace grout or caulk

Goal: If mildew is embedded in grout or caulk and cleaning does not remove it, reseal or replace.

  • Remove old caulk with a utility knife and reseal with a mildew-resistant caulk. For grout, clean and reseal with a grout sealer, or replace if cracked. See fix-grout-is-moldy for grout repair. When you reseal and improve ventilation, mildew should not return.

When to get help

Call a mold remediation professional if:

  • You see thick black mold (slimy, dark, large patches).
  • The affected area is larger than 10 square feet.
  • You have asthma or respiratory issues and are concerned about exposure.
  • You have tried cleaning and mildew returns within days.

Do not attempt to remove large black mold yourself.

Verification

  • The shower surface is pink-, gray-, or black-spot-free. Grout and caulk look clean.
  • No mildew odor. Exhaust fan runs during and after showers.
  • Mildew does not return within a week when you wipe down the shower after use and run the fan.

Escalation ladder

Work from the device outward. Stop when the problem is fixed.

  1. Confirm symptom Verify it is surface mildew (pink, gray, or small black spots), not thick black mold.
  2. Clean with vinegar Spray vinegar, let sit, scrub, rinse.
  3. Clean with bleach If vinegar fails, use diluted bleach (never mix with vinegar).
  4. Improve ventilation Run exhaust fan during and after showers; fix leaks.
  5. Call a pro Black mold, large area (>10 sq ft), or respiratory concerns—call mold remediation.

What to capture if you need help

Before calling support or posting for help, have these ready. It speeds everything up.

  • Whether it is surface mildew or black mold
  • Approximate area affected
  • Whether exhaust fan works
  • Whether vinegar or bleach was tried
  • Steps already tried

Is it surface mildew or thick black mold?

Surface mildew is pink, gray, or small black spots that wipe off. Black mold is thick, slimy, dark, and covers large areas.

Inspect the shower. Surface mildew: pink, gray, or small black spots that wipe off easily. Black mold: thick, slimy, dark green or black, large patches. Good: surface mildew—proceed to clean. Bad: black mold or area >10 sq ft—call a mold remediation pro.

Surface mildew Black mold

You can change your answer later.

Is the bathroom ventilated?

Run the exhaust fan or open a window before cleaning. Bleach requires strong ventilation.

Turn on the exhaust fan or open a window. If using bleach, keep the fan running. Good: air moving. Bad: no fan or window—open a window or delay cleaning until you can ventilate.

Yes No

You can change your answer later.

Open a window or delay until ventilated

If the bathroom is not ventilated, open a window or delay cleaning until you can ventilate. Do not use bleach in a closed room. Once ventilated, proceed to clean with vinegar.

Done

Does vinegar remove the mildew?

Spray white vinegar (1:1 with water), let sit 15 min, scrub with a brush.

Spray white vinegar (1:1 with water) on affected areas. Let sit 15 minutes. Scrub grout and caulk with a brush. Good: mildew disappears or lightens. Bad: mildew remains—try bleach.

Yes No

You can change your answer later.

Does diluted bleach remove the mildew?

Rinse vinegar off first. Never mix bleach with vinegar. Use 1/2 cup bleach per gallon of water.

Rinse vinegar off completely. Mix 1/2 cup bleach per gallon of water. Spray or apply. Let sit 5–10 minutes. Scrub. Wear gloves. Good: mildew gone. Bad: mildew still embedded—may need to replace grout or caulk.

Yes No

You can change your answer later.

Rinse and dry

Rinse all surfaces. Squeegee or towel dry. Run the exhaust fan 30 minutes. Wipe down the shower after each use. Mildew should return more slowly.

Done

Replace grout or caulk

If mildew is embedded in grout or caulk, remove old caulk and reseal. For grout, clean and reseal or replace. See fix-grout-is-moldy. Improve ventilation.

Done

Call a mold remediation pro

Call a mold remediation professional for thick black mold, areas >10 sq ft, or if you have respiratory concerns. Do not DIY large black mold removal.

Done

Reviewed by Blackbox Atlas

Frequently asked questions

Why does mildew grow in my shower?
Mildew thrives in warm, damp, poorly ventilated areas. Soap residue, body oils, and standing water feed it. Run the exhaust fan during and after showers and wipe down walls to reduce moisture.
Can I use vinegar and bleach together?
No. Mixing vinegar and bleach produces toxic chlorine gas. Use one or the other. If cleaning with vinegar first, rinse thoroughly before using bleach.
When should I call a pro for shower mildew?
Call a mold remediation professional if you see thick black mold (slimy, dark, large patches), if mildew covers more than 10 square feet, or if you have respiratory issues and are concerned about exposure.

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