How to Clean Grout: Floors, Showers, and Counters

Grout is the soft, porous line between tiles, and it holds on to everything: soap, oils, dirt, and moisture. White grout turns gray, gray turns brown, and in a Florida shower it can turn black at the edges. The tile may look fine while the grout looks like a mess.

The good news is that grout cleans up better than most people expect, and you do not need harsh chemicals. This guide covers the method for floors, showers, and kitchen counters, and how to seal grout so the work lasts.

What this post covers:

• Know your grout first
• Everyday cleaning with baking soda
• Stronger options for stained grout
• Shower grout and mildew
• Floor and kitchen grout
• Sealing, and how to keep it clean

Know Your Grout First

Before you scrub, find out what you have. The wrong cleaner can etch or discolor certain grout and tile.

• Cement-based grout is the most common. It is porous, so it stains easily and needs sealing.
• Epoxy grout is non-porous and stain-resistant. It cleans easily and does not need sealing.
• Natural stone tile, such as marble, travertine, or limestone, can be etched by acids like vinegar and lemon juice. Use a pH-neutral stone cleaner and keep acid away.
• Colored grout can fade with strong chemicals. Test a hidden spot first.

To test whether grout is sealed, put a few drops of water on it. If the water beads up, it is sealed. If it soaks in and darkens the grout, it needs sealing.

Everyday Cleaning With Baking Soda

This is the gentlest method, and it works on most light to medium staining. It takes more time than force.

1. Sweep or vacuum the area so grit does not scratch the tile while you scrub.
2. Mix baking soda with a little water into a thick paste, like toothpaste.
3. Spread the paste along the grout lines with a spoon or an old toothbrush.
4. Let it sit for 10 to 15 minutes.
5. Scrub with a stiff nylon brush or a grout brush, working along the line rather than across it.
6. Rinse with clean water and wipe dry with a towel.

Skip the wire brush and steel wool. They scratch the tile and wear down the grout, which makes it even more likely to stain later.

Stronger Options for Stained Grout

If baking soda does not do the job, step up gradually. Start with the mildest option, and move on only if you need to.

• Baking soda and hydrogen peroxide: mix into a paste using 3 percent hydrogen peroxide. Apply, let it sit for 15 to 20 minutes, scrub, and rinse. Test a hidden spot, since peroxide can lighten colored grout.
• Baking soda and vinegar: sprinkle baking soda, spray white vinegar, let it fizz, scrub, and rinse. Do not use on natural stone or on grout that is not fully cured.
• Commercial grout cleaner: follow the label, wear gloves, ventilate the room, and rinse well. Never mix products.
• Steam cleaner: a handheld steamer lifts grime from grout without chemicals. Keep it moving, and avoid unsealed grout on delicate tile.

Our own standard services follow a no-bleach policy, and the same is a good idea at home. Chlorine bleach can discolor grout, and it should never be mixed with ammonia or vinegar.

Shower Grout and Mildew

Showers are the hardest place, because they are wet every day and Florida's humidity keeps them damp. Black and pink spots are usually mildew growing on soap film in the porous grout.

• Scrub weekly with a bathroom cleaner or detergent and water. Soap film is the food that mildew grows on.
• Squeegee the walls after every shower. Dry grout does not grow mildew.
• Run the fan during and after the shower for at least 20 minutes.
• If mildew keeps coming back to one spot, check for a crack in the caulk or a leak behind the tile.

EPA's guidance says to scrub mold off hard surfaces with detergent and water and to dry them completely, and that if mold in the shower keeps reappearing, more ventilation and more frequent cleaning will usually keep it to a minimum. Read more in EPA's mold and moisture guide. Our guide to preventing bathroom mold in Florida goes deeper on the routine.

Floor and Kitchen Grout

Floor grout takes the most foot traffic, and kitchen floor grout takes grease too. A few tricks help.

• Mop with a mild cleaner, but use a clean mop head. A dirty mop spreads dirty water into the grout.
• Spray the line with an all-purpose cleaner, wait 5 minutes, and scrub with a brush before you mop.
• For kitchen counters and backsplashes, use a degreaser and a soft brush. Rinse well so food surfaces stay clean.
• Dry the floor after mopping with a towel or a fan, since damp grout attracts dirt.

Heavily stained floor grout may not come all the way clean. If the color will not lift, a grout colorant or regrout can reset the look.

Sealing, and How to Keep It Clean

Cement grout should be sealed after it is clean and completely dry, and again every year or two depending on use. A sealer slows stains and makes everyday cleaning easier.

1. Clean the grout and let it dry for at least 24 hours.
2. Apply the sealer to the grout line with a small brush or applicator bottle, following the label.
3. Wipe sealer off the tile surface before it dries.
4. Wait the time on the label before getting the area wet.

Daily habits help more than a yearly deep scrub: wipe up spills fast, use a mat at the shower and sink, and keep humidity in check. If you would rather hand the job to someone else, our bathroom cleaning service is one way to hand it off, and our deep clean guide lists where grout fits in a full clean.