The grout in my shower is moldy and gross. What is the best grout cleaner to make it look new again?

If your shower grout is genuinely moldy and you want it to look as close to new as possible, I’d go with a bleach-based mold/mildew remover rather than a generic grout cleaner.

My top pick

• Clorox Plus Tilex Mold and Mildew Remover - $6.98 (The Home Depot)

Clorox Plus Tilex Mold & Mildew Remover is my first choice for badly stained white shower grout. It’s specifically formulated for mold/mildew, whitens the staining, and is designed to work with little or no scrubbing. Good Housekeeping's testing also rated Tilex highly for heavily mold-stained grout.

How I'd do it

1. Ventilate the bathroom well—fan on, door/window open.
2. Spray the Tilex directly onto the grout.
3. Let it sit according to the bottle directions.
4. Scrub stubborn areas with a stiff nylon grout brush.
5. Rinse extremely well and let everything dry completely.
6. Once clean and dry, reseal the grout if it's cement-based and unsealed; that helps keep moisture and staining from penetrating.

Important: Don't use bleach products on natural stone such as marble, and don't use them on questionable/unsealed or damaged grout without checking the label. And never mix bleach with vinegar, ammonia, or another cleaner—dangerous fumes can result.

If your grout is colored rather than white, I'd choose a bleach-free option instead. And if the black stuff is actually in the silicone caulk rather than the grout, cleaning may not make it look new—the caulk often needs to be removed and replaced.

If you tell me whether your grout is white or colored and whether your shower tile is ceramic/porcelain, marble, or something else, I can give you the exact cleaner I'd buy and the quickest method.

For moldy, gross shower grout, the "best" cleaner depends on how deep the staining goes, but heavy-duty commercial options and targeted approaches get top marks from experts like The Spruce and The New York Times Wirecutter.

• Best for Heavy-Duty / White Grout: ZEP Grout Cleaner and Brightener Go to product viewer dialog for this item. is an acid-based formula that aggressively lifts deep-set stains, mold discoloration, and grime with minimal scrubbing. (Note: Avoid on natural stone like marble or granite, as acid can etch it).
• Best for Mold & Mildew Stains (Bleach-based): Clorox Clean-Up Cleaner + Bleach Go to product viewer dialog for this item. or Tilex Mold & Mildew Go to product viewer dialog for this item. . Since your issue is specifically mold, sodium hypochlorite (bleach) is unmatched at killing mold roots and instantly whitening dark spores on the surface.
• Best Eco-Friendly / Mild Option: Mrs. Meyer's Clean Day Tub and Tile Cleaner Go to product viewer dialog for this item. is great if you want a pleasant scent and less harsh chemical fumes, though it requires a bit more elbow grease for severe mold.

How to Get the Best Results:

To help narrow down the safest and most effective choice, tell me:

• What type of tile do you have (ceramic, porcelain, or natural stone like marble)?
• Is the grout white or colored?

When dealing specifically with mold and mildew (rather than just general dirt or grease), bleach-based or oxidizing cleaners are your best bet because they actually kill the roots and whiten the dark stains.

Top-Rated Cleaners for Moldy Grout

Add to list Recommended by cleaning experts like The New York Times (Wirecutter) for treating mold and mildew stains. Spray it on, let it sit for a few minutes to let the bleach break down the mold spores, and watch the dark stains disappear with minimal scrubbing.

Add to list Excellent if your grout also has deep-set mineral or dirt grime, though it is acid-based, so use it carefully and avoid letting it sit on nearby metal fixtures.

DIY Hydrogen Peroxide & Baking Soda Paste: If you prefer a non-toxic route, mix equal parts baking soda and hydrogen peroxide into a thick paste, scrub it into the grout lines with a stiff brush, let it sit for 10 minutes, and rinse.

Step-by-Step Game Plan

1. Ventilate the bathroom: Turn on the exhaust fan or open a window; bleach and commercial sprays emit strong fumes.
2. Apply the cleaner: Spray your bleach-based cleaner (like Tilex or Clorox) generously onto the dry, moldy grout lines.
3. Let it dwell: Give it 5 to 10 minutes to work its chemical magic. Don't let it dry completely.
4. Scrub gently: Use a dedicated OXO Grout Brush Go to product viewer dialog for this item. or any medium-stiff nylon bristle brush to agitate the cleaner along the lines.
5. Rinse thoroughly: Wash away the residue with warm water.
6. Seal it (Crucial final step): Once the grout is completely dry (wait 24 hours), apply a penetrating grout sealer . Grout is porous—sealing it blocks moisture and prevents the mold from coming right back.

If you'd like, let me know:

• Is your tile natural stone (like marble or travertine) or standard ceramic/porcelain? (Bleach can ruin natural stone!)
• Do you prefer a commercial bleach spray or a natural/DIY approach?

I can help you adjust the cleaner choice to protect your specific shower surfaces.

If your shower grout is black, moldy, and looks beyond “dirty,” you’ll usually get the best results from a mold/mildew remover first, then a grout cleaner if needed. A regular grout cleaner often removes grime but won’t tackle stubborn mildew staining as well.

My top picks:

1. **Best for “make it look new again” results:

**

• Best for white shower grout with black mold/mildew staining.
• The bleach-based formula is very effective at whitening grout and removing mildew stains.
• Use with good ventilation and don’t mix it with other cleaners.

1. **Best heavy-duty option:

**

• Great for stubborn black staining on grout and caulk.
• It’s designed to attack mold/mildew stains quickly, often with little scrubbing.

1. **Best grout-specific cleaner after mold removal:

**

• Good if the grout is stained from soap scum, mineral buildup, and mildew.
• It’s bleach-free and has an EPA Safer Choice designation.

1. **Best non-bleach grout cleaner for regular maintenance:

**

• A strong grout cleaner for dirt and discoloration, especially if you have colored grout or don’t want bleach.

The method that usually works best

1. Spray a mold/mildew remover onto the grout.
2. Let it sit according to the label (don’t let it dry out).
3. Scrub with a stiff grout brush or an electric scrubber.
4. Rinse thoroughly.
5. After it dries, apply a grout sealer if the grout is porous.

A small grout brush makes a huge difference; powered scrubbers can save a lot of elbow grease on a large shower.

A couple of cautions:

• If your grout is colored, avoid bleach products unless the label says they’re safe for it.
• If the “mold” is actually in silicone caulk, cleaning may not restore it; replacement is often the only way to get it white again.
• Don’t mix bleach products with vinegar, ammonia, or other cleaners.

If you tell me whether your grout is white or colored, and whether the mold is surface black spots vs. deep black staining, I can narrow it down to the best product.

If your shower grout is black/moldy and you want it to look as close to new as possible, I’d go with a bleach-based mold & mildew remover, rather than a general-purpose grout cleaner.

🥇 Best overall: Clorox Tilex Mold & Mildew Remover

Clorox Plus Tilex Mold and Mildew Remover

$6.98

It’s specifically designed for mold/mildew stains on bathroom surfaces and grout, and its bleach formula is particularly good at whitening the grout back toward its original color. It currently has a 4.7/5 rating from more than 1,600 reviews in the product results I checked.

🥈 If the grout is really nasty: Zep Mold & Mildew Stain Remover

Zep Mold Stain & Mildew Stain Remover Gel

$98.76

I especially like the gel version for shower grout because it clings to vertical grout lines instead of immediately running down the wall. Zep also makes a spray specifically formulated for grout and tile.

🥉 Best bleach-free option: CLR Mold & Mildew

CLR Mold & Mildew Clear Cleaner Remover

$6.58

This is a good choice if you don't want bleach. It's formulated for mold/mildew stains on surfaces including bathroom tile and grout.

What I'd actually do

1. Ventilate the bathroom well and wear gloves/eye protection.
2. Spray Tilex directly onto the moldy grout.
3. Let it sit for the label-specified dwell time rather than immediately scrubbing.
4. Scrub stubborn grout with a stiff nylon grout brush.
5. Rinse thoroughly.
6. Repeat once if necessary.

Very important: Never mix bleach-based cleaners with vinegar, ammonia, acids, or other bathroom cleaners. That can create dangerous fumes.

One caveat: if the grout itself has deteriorated, cracked, or permanently discolored, no cleaner will truly make it look new. In that case, cleaning followed by grout recoloring/sealing can produce a much more dramatic transformation.

If you want, I can also give you the “nuclear option” for absolutely disgusting shower grout—the method I'd use when ordinary Tilex doesn't get it white again.

Getting mold and grime out of shower grout can be a real pain, but you can definitely get it looking brand new again. Here are the best options depending on how tough the stain is:

• Commercial Heavy-Duty Cleaner: Clorox TileX Mold and Mildew Remover Go to product viewer dialog for this item. or Zep Grout Cleaner and Whitener Go to product viewer dialog for this item. are fantastic commercial options. Zep is an acid-based cleaner that eats right through tough mineral deposits and deep-set grime, while TileX uses bleach to instantly blast away black mold stains.
• DIY Oxygen Bleach / Baking Soda Paste : If you prefer a non-toxic approach, mix equal parts baking soda and hydrogen peroxide (or water) into a thick paste. Scrub it into the grout lines with a stiff-bristled brush, let it sit for 10–15 minutes, and rinse. It lifts stains naturally without harsh fumes.
• Steam Cleaning : If chemicals aren't doing the trick, a handheld pressurized steam cleaner uses high heat to blast mold, mildew, and bacteria straight out of the porous grout lines without any scrubbing at all.

Pro-tip : Once it’s clean and completely dry, apply a penetrating grout sealer (like Miracle Sealants 511 Impregnator Go to product viewer dialog for this item. ) to block out future moisture, mold, and stains.

If you'd like, let me know:

• Is your tile ceramic, porcelain, or natural stone (like marble or travertine)?
• Are the grout lines sealed or unsealed?

I can tell you which cleaner is safest so you don't damage your specific tile surface.

If your shower grout is white and badly moldy/mildewed, I’d go with a bleach-based mold/mildew remover, rather than a generic grout cleaner.

Clorox Plus Tilex Mold & Mildew Remover

$6.98

My top pick: Clorox Plus Tilex Mold & Mildew Remover

It’s particularly good for the black/gray discoloration that makes shower grout look disgusting. Good Housekeeping rated Tilex its best bleach-based grout cleaner, noting that it can kill mold/mildew and whiten the staining with little or no scrubbing.

How I'd use it:

1. Ventilate the bathroom well and put on gloves.
2. Spray the grout thoroughly.
3. Let it sit according to the label—Clorox's foaming version specifies 5 minutes of wet contact time.
4. Rinse very thoroughly.
5. For stubborn spots, use a stiff nylon grout brush and repeat rather than attacking it with excessive force.

Important: Don't use bleach products on natural stone such as marble, and don't mix bleach with vinegar, ammonia, or other cleaners. The EPA specifically cautions against mixing bleach with ammonia-containing products.

If you want something less harsh

CLR Mold & Mildew Clear

$6.58

This is bleach-free and EPA Safer Choice certified, but it's more of a stain/mildew cleaner than the nuclear option for really black, nasty grout.

One important caveat

If the grout is actually deteriorating, cracked, or permanently black despite cleaning, the problem may be underneath the surface or in the caulk. Cleaning can make it dramatically better, but it can't restore missing grout. Also, keeping the shower dry afterward—fan running and/or squeegeeing—helps prevent the mold from coming right back.

If you tell me whether your grout is white or colored and whether your shower tile is ceramic/porcelain, glass, or natural stone, I can tell you the exact cleaner I'd buy and the fastest way to get it looking almost new.

To make moldy, gross shower grout look new again, the "best" cleaner depends on whether you are dealing with stubborn surface mold stains or deeply embedded grime. Because grout is porous , surface-level bleaching isn't always enough—you need something that kills the mold roots and lifts the discoloration.

Top Commercial Grout & Mold Cleaners

• Best for Severe Mold Stains (Scrub-Free): Clorox Plus Tilex Mold and Mildew Remover Go to product viewer dialog for this item. or Zep Mold and Mildew Stain Remover Go to product viewer dialog for this item. . These bleach-based sprays instantly whiten dark mold and mildew stains on contact. You simply spray them on, let them sit for 5 minutes, and rinse—minimal scrubbing required. (Note: Wear a mask and ventilate well; do not mix with other cleaners.)
• Best for Deep-Set Grime & Restoration: Zep Grout Cleaner and Brightener Go to product viewer dialog for this item. . This is an acid-based liquid designed for neglected, deeply discolored grout. It literally bubbles up to lift embedded dirt, though it requires careful rinsing and shouldn't be used on natural stone.
• Best Gel-Based Option for Vertical Walls: Mold Stain Remover Gels (such as *Active Go to product viewer dialog for this item. * or *Skylarlife Go to product viewer dialog for this item. * gel). Instead of running down the wall like a liquid spray, you squeeze these thick gels directly onto vertical grout lines, let them sit for 3 to 5 hours (often while you sleep or go out), and wipe/rinse them away to reveal stark white grout.

The Best DIY Natural Alternative

If you prefer a non-toxic approach without harsh bleach fumes, a paste made from baking soda and 3% hydrogen peroxide is a favorite among cleaning experts:

1. Mix baking soda and hydrogen peroxide in a small bowl until it forms the consistency of a runny toothpaste.
2. Smear the paste directly onto the grout lines.
3. Let it fizz and sit for 10–15 minutes, then scrub it in using an angled grout brush or an old toothbrush.
4. Rinse thoroughly with warm water.

Pro-Tip for Long-Term Results

Once your grout is clean and completely dry, apply a grout sealer (like Custom Building Products or Miracle Sealants ). Grout is a sponge for moisture, soap scum, and mold spores; sealing it creates a barrier that keeps future mold from embedding itself into the pores.

To help narrow down the best fix, tell me:

• Is your tile made of ceramic/porcelain or natural stone (like marble or granite)?
• Is the mold mostly on the surface or deeply embedded into the grout?

If your shower grout is actually moldy/black and you want it to look as close to new as possible, I’d go with a bleach-based mold/mildew remover, rather than a generic grout cleaner.

Clorox Plus Tilex Mold & Mildew Remover

$9.88

🥇 My pick: Clorox Plus Tilex Mold & Mildew Remover

It’s specifically formulated for shower mold and mildew, and Clorox says it kills 99.9% of mold and mildew while removing the discoloration. Good Housekeeping also ranks it among its top mold/mildew removers.

For really stubborn grout:

Zep Mold & Mildew Stain Remover Gel

$7.98

The Zep gel is excellent because it clings to vertical grout instead of immediately running down the wall. It's particularly good for those little black spots that have been there forever.

How I'd do it

1. Ventilate the bathroom well and put on gloves.
2. Spray the Tilex directly onto the moldy grout.
3. Let it sit according to the bottle directions—don't let it dry out.
4. Scrub with a stiff nylon grout brush.
5. Rinse extremely well.
6. Let the grout dry completely.

For severe staining, a second application may make a huge difference. Bleach-based cleaners are particularly effective at whitening badly stained grout.

Important: Don't mix bleach products with vinegar, ammonia, toilet-bowl cleaners, or other cleaning chemicals. And if your grout is colored or your tile is natural stone (marble, travertine, etc.), tell me before using bleach—the recommendation changes.

If you want, send me a picture of the grout, and I can tell you whether I'd use Tilex, Zep gel, peroxide/oxygen bleach, or whether the grout is too far gone and should be regrouted.

• Oxygen bleach powder is fantastic for overall maintenance and lifting deep-seated grime without harsh chlorine fumes. Mix it with a little warm water to form a paste, scrub, let it sit for 15 15 1 5 to 30 30 3 0 minutes, and rinse.
• Chlorine bleach-based sprays (like Tilex Go to product viewer dialog for this item. or Clorox Cleanup Go to product viewer dialog for this item.) work quickly to kill and bleach out active mold/mildew stains on white grout, though they have a strong chemical smell and require good ventilation.
• Hydrogen peroxide and baking soda is a great DIY powerhouse. Mix them into a thick paste, apply it to the grout lines, scrub with a stiff-bristled brush, and rinse.
• Commercial acid-based or heavy-duty alkaline cleaners (like Miracle Sealants Heavy Duty Cleaner Go to product viewer dialog for this item. or Sulfamic Acid Go to product viewer dialog for this item. alternatives) are best if the grout is severely discolored, stained, or scaled with hard water deposits.

Tips for the best results:

1. Preparation : Spray the area with warm water first and make sure the space is well-ventilated.
2. The Right Tool : Use a dedicated grout brush (which has stiff, V-shaped bristles) rather than a regular toothbrush to get deep into the lines.
3. Sealing : Once the grout is completely clean and dry (24 24 2 4 to 48 48 4 8 hours later), apply a penetrating grout sealer to prevent future mold and mildew from taking root.

Would you like recommendations on whether to use a natural DIY option or a store-bought chemical cleaner , depending on whether your tile is ceramic, porcelain, or natural stone?