The most effective way to clean grout between floor tiles is to apply a paste of baking soda and water (or baking soda and hydrogen peroxide), let it sit for 10-15 minutes, then scrub with a stiff grout brush and rinse. For heavier staining or mold, use diluted bleach (1:4 with water) or a commercial grout cleaner like Zep Grout Cleaner. Always seal the grout after cleaning to prevent future buildup.
Floor grout gets dirtier faster than wall grout because it’s horizontal – dirt, grime, and moisture all settle directly into it. The good news is that floor grout is usually more durable than bathroom wall grout and can handle more aggressive cleaning methods.
Cleaning Methods by Grout Condition
|
Grout Condition |
Recommended Method |
Time to Work |
|
Light dirt / regular maintenance |
Warm water + dish soap, stiff brush |
5-10 min |
|
Moderate buildup / grey grout |
Baking soda paste + white vinegar spray |
15 min |
|
Discolored / stained grout |
Baking soda + hydrogen peroxide paste |
20-30 min |
|
Mold or black grout |
Diluted bleach solution (1:4) or Zep |
10-15 min contact |
|
Heavily neglected |
Steam cleaner or professional grout cleaning |
Variable |
Step-by-Step: Baking Soda + Hydrogen Peroxide Method
Step 1 – Sweep or vacuum the floor first to remove loose debris.
Step 2 – Make the paste: Mix baking soda with hydrogen peroxide (3%) to form a thick paste.
Step 3 – Apply to grout lines: Spread the paste along the grout with a spatula, old toothbrush, or gloved finger. Work in small sections.
Step 4 – Let sit: 15-20 minutes minimum, longer for stubborn staining.
Step 5 – Scrub: Use a stiff grout brush or a drill-mounted brush attachment for large areas. Scrub along the grout line direction.
Step 6 – Mop and rinse: Go over the whole floor with a damp mop to remove the paste and loosened grime. Follow with a clean water rinse mop.
Tools That Make the Job Easier
- Drill brush attachment – fits a standard drill and covers large floor areas in a fraction of the time
- Narrow grout brush – for precise work in tight or particularly dirty lines
- Steam cleaner – steam penetrates grout pores and loosens buildup without chemicals; very effective for regular maintenance
- Oxygen bleach powder (OxiClean) – mix with water, mop onto floor, let soak 15-30 minutes, then mop off
Bleach Method for Moldy or Black Grout
Mix 1 part chlorine bleach with 4 parts water in a bucket. Apply to grout with a brush, let sit 10 minutes, then scrub and rinse thoroughly. Work in a ventilated area and wear gloves. Never mix bleach with vinegar – this creates toxic chlorine gas. Do not use bleach on colored grout as it will remove the color.
Sealing Grout After Cleaning
After a deep clean, apply a penetrating grout sealer. It fills the pores in the grout and makes future cleaning dramatically easier – grime stays on the surface instead of soaking in. Most sealers are applied with a small brush along the grout lines and take 30-60 minutes to dry. Reapply every 1-2 years.
Final Thoughts
The baking soda and hydrogen peroxide paste handles most floor grout effectively. For mold or severe discoloration, diluted bleach is faster. Sealing the grout after cleaning is the best investment for long-term maintenance – a sealed floor stays clean with basic mopping rather than periodic scrubbing sessions.










