How to Clean Grout: 4 Methods That Actually Work

Grout is porous, which means it soaks up dirt, soap scum and mildew much faster than the tiles around it. If your bathroom or kitchen floor looks dingy even after you mop, the grout is usually the reason. Here are four methods, from the gentlest to the strongest, so you can choose the one that fits how dirty your grout is.

What You'll Need

• A stiff grout brush or an old toothbrush
• Baking soda
• 3% hydrogen peroxide
• Oxygen bleach powder (optional)
• A spray bottle
• Warm water and a bucket
• Rubber gloves

Method 1: Baking Soda Paste (Light Dirt)

1. Mix baking soda with a little water until it forms a thick paste.
2. Spread it along the grout lines with your finger or the brush.
3. Let it sit for 10 minutes.
4. Scrub along the lines, then rinse with warm water and wipe dry.

This is a great routine clean and is safe for all grout types.

Method 2: Baking Soda and Hydrogen Peroxide (Stains and Discoloration)

1. Mix 1/2 cup baking soda with about 1/4 cup hydrogen peroxide to form a paste.
2. Apply it to the grout and let it sit for 10–15 minutes. You may see it bubble slightly.
3. Scrub and rinse.

Hydrogen peroxide has a mild whitening effect, which makes this method especially good for white or light-colored grout that has turned gray.

Method 3: Oxygen Bleach (Deep Cleaning)

Oxygen bleach (sodium percarbonate) is gentler than chlorine bleach and doesn't have the strong smell.

1. Dissolve oxygen bleach in warm water according to the package directions.
2. Pour or sponge the solution over the grout lines and let it soak for 10–15 minutes.
3. Scrub well, then rinse the floor with clean water.

This is the best option for large floors with heavily stained grout.

Method 4: Steam Cleaning (Tough, Set-In Grime)

A handheld steam cleaner with a small brush attachment can blast dirt out of grout without any chemicals. Work in small sections and wipe away the loosened dirt right away. Check your tile manufacturer's guidelines first, since steam isn't recommended for some natural stone or older, cracked grout.

What About Vinegar?

Vinegar is popular, but it's acidic, and using it often can slowly break down cement-based grout and etch natural stone like marble or travertine. It's fine for an occasional clean on sealed ceramic tile, but it shouldn't be your go-to grout cleaner.

Safety Note

Never mix chlorine bleach with vinegar, ammonia or other cleaners. If you use chlorine bleach on very stubborn mildew, use it on its own in a well-ventilated room and rinse thoroughly.

How to Keep Grout Clean

• Seal your grout once it's clean and completely dry. A grout sealer helps stop stains from soaking in. Most grout should be resealed every 1–2 years.
• Squeegee shower walls after each use to reduce soap scum and mildew.
• Clean grout lines lightly once a month with Method 1, so they never get badly stained again.

FAQ

How do I know if my grout needs sealing? Drop a little water on the grout. If it darkens quickly, the water is soaking in, and the grout needs sealing.

Can I use a drill brush? Yes. A drill brush attachment saves a lot of time on large floors. Use a medium-stiff brush and don't press too hard.

What if the grout is still stained after cleaning? Some stains are permanent. A grout colorant or grout pen can refresh the look without replacing the grout.