How to Clean Grout Between Tiles

Grout is the porous cement-based material that fills the joints between tiles. Because it's porous, it absorbs dirt, grease, soap scum, and moisture over time — turning from bright white or gray to a dingy, discolored mess. Regular grout cleaning is one of the most impactful things you can do to make your tile floors and walls look fresh and well-maintained. Here's a complete guide.

Why Grout Gets Dirty So Fast

Grout is essentially a porous sponge. Every time you mop the floor, dirty water flows into the grout lines and deposits soil. Foot traffic grinds dirt into grout. In bathrooms, soap scum and mildew accumulate. Without regular cleaning and sealing, grout darkens progressively and becomes increasingly difficult to restore.

What You'll Need

• Nutricost Baking Soda (2 LBS) – gentle abrasive and deodorizer
• Lucy's Family Owned Distilled White Vinegar (1 Gallon) – for light grout cleaning (not on natural stone)
• FOLEX Instant Carpet Spot Remover – surprisingly effective on grout stains
• Hydrogen peroxide (3%) – for whitening and mildew
• A stiff grout brush or old toothbrush
• HOMEXCEL Microfiber Cleaning Cloths (Pack of 12)
• Empty Spray Bottles (16oz, 2-Pack)
• Warm water
• Grout sealer (for after cleaning)

Method 1: Baking Soda and Vinegar (Best for General Grout Cleaning)

This is the most effective and safest home method for cleaning grout on ceramic and porcelain tile. Do not use vinegar on natural stone tile grout.

1. Sprinkle baking soda generously along the grout lines.
2. Spray white vinegar over the baking soda. It will fizz — this reaction helps lift dirt from the porous grout.
3. Let the fizzing reaction work for 5–10 minutes.
4. Scrub the grout lines firmly with a stiff grout brush or old toothbrush. Use short, back-and-forth strokes along the grout line.
5. Rinse thoroughly with warm water and wipe clean with a microfiber cloth.
6. Repeat for heavily soiled areas.

Method 2: Baking Soda Paste (Gentle, Safe for All Grout)

For natural stone tile or when you want to avoid vinegar:

1. Mix baking soda with just enough water to form a thick paste.
2. Apply the paste directly to the grout lines using your finger or a brush.
3. Let it sit for 10–15 minutes.
4. Scrub firmly with a grout brush.
5. Rinse thoroughly with warm water.

Method 3: Hydrogen Peroxide (For Whitening and Mildew)

Hydrogen peroxide is a mild bleaching agent that whitens grout and kills mildew without the harshness of chlorine bleach.

1. Pour 3% hydrogen peroxide into a spray bottle.
2. Spray directly onto the grout lines.
3. Let it sit for 10–15 minutes.
4. Scrub with a grout brush.
5. Rinse thoroughly.

For extra cleaning power, make a paste of hydrogen peroxide and baking soda. Apply to grout, let sit 15 minutes, scrub, and rinse.

Method 4: Steam Cleaning (For Deep Grout Cleaning)

A steam cleaner is highly effective for deep grout cleaning — the high-temperature steam penetrates the porous grout and loosens embedded dirt without chemicals. Use the grout attachment nozzle and work slowly along each grout line. Wipe away loosened dirt with a microfiber cloth immediately after steaming.

For Severely Stained or Moldy Grout

For grout that hasn't been cleaned in years or has significant mold:

1. Apply undiluted hydrogen peroxide or a commercial grout cleaner to the grout lines.
2. Let it dwell for 20–30 minutes.
3. Scrub vigorously with a stiff grout brush.
4. Rinse thoroughly.
5. For black mold in grout, a diluted bleach solution (1 part bleach to 10 parts water) on ceramic/porcelain tile is effective. Never use bleach on natural stone.

Sealing Grout After Cleaning

This is the most important step that most people skip. After cleaning grout, apply a grout sealer to fill the pores and create a protective barrier that prevents future staining.

• Allow cleaned grout to dry completely (24–48 hours) before sealing.
• Apply grout sealer with a small brush or applicator along each grout line.
• Wipe away any sealer that gets on the tile surface immediately.
• Allow to cure according to product instructions before getting wet.
• Reseal annually or every 2 years depending on traffic and use.

Maintaining Clean Grout

• Seal grout annually to prevent staining.
• Wipe up spills on grout immediately before they absorb.
• Include grout lines in your regular floor cleaning routine.
• Use a pH-neutral floor cleaner that won't break down grout sealer.
• Run the bathroom exhaust fan during and after showers to reduce moisture and mildew in bathroom grout.

Final Thoughts

Clean grout transforms the entire appearance of a tiled surface. The baking soda and vinegar method handles most grout cleaning effectively, while hydrogen peroxide whitens and kills mildew. The single most impactful thing you can do after cleaning is to seal the grout — it dramatically reduces how quickly grout re-soils and makes future cleaning much easier.