How to Clean Mold from Grout Without Bleach

Written by Mike Kapur | Edited by Eric McClure

Last Updated: May 28, 2022 References

If you only see dark gunk in the grout and/or on the shower curtain in your home, the odds are actually extremely low that you’re dealing with actual mold. It’s much more likely that you’ve got mildew—mold’s less scary and less dangerous little cousin.^{[1]
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Expert Source

Mike Kapur
Certified Mold Assessor & Home Inspector, Sonic Home Inspections
Expert Interview. 19 August 2020.} Regardless, it makes sense that you’d want to avoid the noxious fumes of bleach to deal with mildew. The good news is that there are a ton of options. We’ll walk you through how to fix the problem regardless of whether you’ve got mold or mildew.

This article is based on an interview with our certified mold assessor & home inspector, Mike Kapur, owner of Sonic Home Inspections. Check out the full interview here.

1

Put on protective gear to avoid inhaling mold.

The odds are high you don’t have mold, but better safe than sorry. It’s impossible for you to know whether you’re actually dealing with mold without sending a sample into a lab for an analysis.^{[2]
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Expert Source

Mike Kapur
Certified Mold Assessor & Home Inspector, Sonic Home Inspections
Expert Interview. 19 August 2020.} If you only see it in your grout and on your shower curtain, it’s probably mildew, which isn’t nearly as serious as mold.^{[3]
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Expert Source

Mike Kapur
Certified Mold Assessor & Home Inspector, Sonic Home Inspections
Expert Interview. 19 August 2020.} In either case, play it safe by putting on an N-95 mask or respirator, put goggles on, and wear long sleeves and gloves.^{[4]
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Trustworthy Source
United States Environmental Protection Agency
Independent U.S. government agency responsible for promoting safe environmental practices
Go to source}
- On the off chance that it does happen to be mold, you really don’t want to breathe the spores in or get them on your skin. Mold is extremely bad for your health, and it can lead to health complications down the line.^{[5]
  X
  Trustworthy Source
  United States Environmental Protection Agency
  Independent U.S. government agency responsible for promoting safe environmental practices
  Go to source}

2

Try a vinegar and water spray for a non-abrasive option.

Mix your ingredients in a spray bottle and coat the mold thoroughly. Use at least 2 cups (470 mL) vinegar for every 1 cup (240 mL) of tap water. Spray, let the vinegar and water soak for at least 30 minutes, and then wipe the clean with a paper towel.^{[6]
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Expert Source

NW Maids
House Cleaning Service
Expert Interview. 28 August 2019.}
- Rinse the grout with water once all of the mold is gone.
- This will put minimal wear and tear on your grout.

3

Make a vinegar and soda paste for something stronger.

For something stronger, cover the grout with a baking soda paste. This combination will foam up, so mix it in the shower wherever you plan on applying it. Fill a small container with a spoonful of baking soda and pour a little bit of vinegar over it. Mix it up to make a paste-like material and rub it over the mold. Wait a minute or 2 and wipe the paste off to remove the mold.^{[7]
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Expert Source

Marcus Shields
House Cleaning Professional
Expert Interview. 22 September 2019.}
- Rinse the area thoroughly when you’re done.
- This may get a little messy, so wear long sleeves. The mixture will also create a carbon dioxide gas, so do this in a well-ventilated area.^{[8]
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4

Cover the mold with ammonia if you have tile.

Fill a spray bottle with ammonia and cover the mold liberally. Wait a few minutes to give the ammonia time to settle into the grout, and then wipe the grout away with paper towels. If the mold doesn’t come off, you may need to scrub a little bit with a sponge or scrub brush.^{[9]
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Expert Source

Mike Kapur
Certified Mold Assessor & Home Inspector, Sonic Home Inspections
Expert Interview. 19 August 2020.}
- Do not use ammonia if the grout is surrounded by natural stone. Natural stone is porous and ammonia is caustic, so it may damage the stone.^{[10]
  X
  Expert Source
  
  Marcus Shields
  House Cleaning Professional
  Expert Interview. 22 September 2019.}
- Rinse the grout with water when you’re done.
- Ammonia is corrosive, so don’t leave it on the grout for too long. Also, keep the room well-ventilated while you work. Ammonia fumes can damage your lungs.^{[11]
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5

Go for an enzyme cleaner for a natural option.

Enzyme cleaners are an organic way to remove moldy residue with no odors. Any enzyme cleaner should work, although Bio Clean is a popular option that should get the job done. Simply spray the moldy area and scrub the mold off with a stiff brush. When you’re done, rinse the area off.^{[12]
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Expert Source

Marcus Shields
House Cleaning Professional
Expert Interview. 22 September 2019.}
- Bio Clean is a 100% organic cleaner that is even capable of cleaning septic tanks.^{[13]
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6

Use a steam cleaner to physically erode the mold.

Put a brush on your steam cleaner and rub the mold away. This may seem like a counterintuitive option since mold feeds on moisture.^{[14]
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Expert Source

Mike Kapur
Certified Mold Assessor & Home Inspector, Sonic Home Inspections
Expert Interview. 19 August 2020.} The extreme heat and pressure from the steam cleaner will physically break the fungal spores apart, though! Use the highest temperature and pressure setting. Then, move the brush back and forth along the moldy grout until it totally dissipates.^{[15]
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- The moisture from the steam may end up deep in the grout. Air out the area thoroughly over the course of 1-2 days to keep the grout from developing more mold.

7

Try hydrogen peroxide if the tile or stone isn’t colorful.

Any solution 3% or stronger will do the trick with grout. Bleach is a great way to kill mold, but only on non-porous surfaces—hydrogen peroxide is actually better than bleach for porous materials like grout. Fill a spray bottle with the hydrogen peroxide, coat the moldy grout, and wait 10 minutes. Then, scrub the area with a sponge or stiff brush.^{[16]
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- Rinse the area off with water when you’re done.
- If you have painted tiles or grout, the hydrogen peroxide may cause discoloration. You may want to spot test the peroxide in an inconspicuous area first.

8

Use a grout cleaner for any non-mold dirt.

If you’re pretty sure it’s just mildew, use a standard grout cleaner. These cleaners may kill mold too, but they’re probably not the best at that. If you’ve got discolored grout, swing by a home cleaning supply store and pick up any specialized grout cleaner. Follow the instructions on the label to apply the cleaner to your grout.^{[17]
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- Read the labels carefully! Some of these cleaners actually contain bleach. If you’re actively trying to avoid using bleach, pick up a grout cleaner that doesn’t list it in the ingredients.^{[18]
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9

Hire a professional if the moldy area is huge.

If the mold covers more than a 3 by 3 ft (0.91 by 0.91 m) area, call a pro. If you do suspect you have mold and it’s covering an especially large area, contact a mold remediation company. Larger and particularly aggressive mold infestations are not DIY jobs, and you are unlikely to be able to handle the issue on your own. Play it safe and reach out to a pro.^{[19]
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United States Environmental Protection Agency
Independent U.S. government agency responsible for promoting safe environmental practices
Go to source}
- When a mold infestation is this large, the problem may have spread to your HVAC system, wall interior, or pipes. Since mold poses a health risk, you really need a professional to resolve the issue 100%.^{[20]
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  Trustworthy Source
  United States Environmental Protection Agency
  Independent U.S. government agency responsible for promoting safe environmental practices
  Go to source}

10

Reseal the grout to keep the mold from coming back.

Once your grout is clean, reseal it to keep the problem out for good. Regardless of the cleaning method you chose, the problem may come back again if you don’t seal the grout off.^{[21]
X
Research source} Let your bathroom air out for 48-72 hours and pick up a grout resealer. If it’s a liquid or gel sealant, follow the directions on the label to apply it directly to the grout. For foam sealers, you spray or paint the sealant onto the grout.^{[22]
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- It may take multiple applications depending on the specific sealant you choose. You typically must wait 24 hours between coats for the layers to dry.^{[23]
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- You should reseal your grout at least once a year to keep the grout from falling apart over time.^{[24]
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11

Keep the area well-ventilated to prevent new mold growth.

To keep the mold/mildew from coming back, improve your ventilation. Both mold and mildew thrive on moisture. Improving the airflow in your bathroom or kitchen should help prevent this issue from coming back. Crack a window, run some fans, or turn a dehumidifier on if need be. Whatever you can do to decrease the moisture and relieve steam will dramatically help prevent this in the future.^{[25]
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Expert Source

Mike Kapur
Certified Mold Assessor & Home Inspector, Sonic Home Inspections
Expert Interview. 19 August 2020.}
- If the mold or mildew keeps showing up after you improve the ventilation, there may be a leak in your wall behind the tile. Reach out to a plumber to see if they can investigate the source of the problem.^{[26]
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  Trustworthy Source
  United States Environmental Protection Agency
  Independent U.S. government agency responsible for promoting safe environmental practices
  Go to source}