How to Clean Grout: Pro Tips for Sparkling Tile

Updated March 28, 2026 • 7 min read • By National Cleaner Connect

Grout cleaning is one of the most searched home cleaning topics — and for good reason. Dirty grout makes even spotless tile look grimy. The good news: you don't need expensive tools or harsh chemicals to get great results. Here's what professional cleaners actually use.

Why Grout Gets Dirty

Grout is porous cement. Unlike glazed tile, grout absorbs moisture, dirt, oils, soap residue, and mold spores. Over time, this buildup discolors the grout from light to dark — especially in high-moisture areas like showers, kitchen floors, and entryways.

Regular mopping actually makes grout dirtier if you use too much cleaning solution — the soap residue settles into grout lines and attracts more dirt. This is why "the cleaner the tile, the dirtier the grout" is such a common complaint.

Method 1: Baking Soda + Hydrogen Peroxide (Best DIY Method)

This is what most professional cleaners use for routine grout cleaning:

1. Mix baking soda with hydrogen peroxide (3%) into a thick paste
2. Apply the paste directly to grout lines
3. Let it sit for 10–15 minutes (longer for heavily stained grout)
4. Scrub with a stiff nylon brush (old toothbrush for corners, grout brush for larger areas)
5. Rinse thoroughly with clean water
6. Wipe dry — don't let dirty water sit on the grout

For stubborn stains, add a squirt of dish soap to the paste. The surfactants in dish soap help lift grease and body oils.

Method 2: Oxygen Bleach (OxiClean)

Oxygen bleach is the professional's go-to for heavy grout staining:

• Dissolve oxygen bleach powder in warm water per package directions
• Pour or spray onto grout lines generously
• Let sit 15–30 minutes (up to an hour for severe staining)
• Scrub and rinse

Oxygen bleach is color-safe, non-toxic, and won't discolor colored grout — unlike chlorine bleach, which can.

Method 3: Steam Cleaning

Steam cleaners are the chemical-free option. The high-temperature steam (212°F+) sanitizes and loosens grime without any cleaning products. Best for:

• Homes with children or pets (no chemical residue)
• Bathrooms with mold and mildew
• Regular maintenance cleaning

A quality handheld steamer with grout attachments costs $50–$150. Professional cleaning services use commercial steam units that are even more powerful.

What NOT to Use on Grout

• Chlorine bleach: Can discolor colored grout and break down sealant
• Vinegar on natural stone: Acid damages marble, travertine, and limestone tile and grout
• Wire brushes: Scratch tile and destroy grout — use nylon brushes only
• Ammonia-based cleaners: Can discolor grout over time

Sealing Grout: The Key to Staying Clean

After deep cleaning, applying a grout sealer prevents future staining by blocking the pores that absorb dirt. Apply sealer once per year in high-traffic areas and every 2–3 years elsewhere. Sealers cost $10–$20 per bottle and take about 30 minutes to apply.

When to Hire a Professional Cleaner

Call a pro when:

• DIY methods haven't worked after multiple attempts
• Grout has deep mold growth (black spots that don't come clean)
• Large areas need cleaning (full kitchen floor, entire shower)
• You want professional steam or rotary cleaning
• Grout needs recoloring or regrouting

Professional grout cleaning typically costs $1–$3 per square foot. Find qualified cleaners in the National Cleaner Connect directory.