How to Clean Bathroom Grout and Remove Mold from Tile

Bathroom grout and tile take a beating. The constant moisture, temperature swings, and soap residue create the exact conditions mold and mildew love. Left alone, grout darkens, mold spreads into tile joints and behind walls, and what started as a cosmetic problem becomes a structural one. The good news: you can reclaim your tile without chemicals that make you lightheaded or tools that tear into the grout itself. The work is straightforward, the materials are cheap, and the results are visible the same day. Done right, your grout will be bright again and the mold will stay gone for months.

1. Air Out the Space First. Open windows, run the exhaust fan, and leave the bathroom door open. If there's no exhaust fan, prop a box fan in the window facing outward. Ventilation moves the chemical fumes out and helps dry the tile as you work. Wait five minutes for air to circulate before you start.
2. Strip Away Buildup. Use a plastic scraper or old credit card to scrape away soap scum, toothpaste buildup, and loose debris from the grout lines. Work at a 45-degree angle so you don't gouge the grout. Wipe the tile with a damp cloth to clear away the scraped material.
3. Pick Your Weapon. For light staining and surface mold, use white vinegar full-strength in a spray bottle. For moderate to heavy mold or stubborn stains, mix one part bleach to three parts water in a spray bottle. For grout that's never been sealed and needs deep cleaning, use a commercial grout cleaner like oxygen-based tile cleaner. Bleach is the most aggressive; use it only if vinegar doesn't work or mold returns quickly.
4. Let It Soak In. Spray the cleaner directly onto the grout joints and surrounding tile. Work in a 3-by-3-foot section so the solution doesn't dry before you scrub. Let it sit for 5–10 minutes if using vinegar, 10–15 minutes for bleach solution, or follow the product instructions for commercial cleaners. The solution needs time to break down mold and stains.
5. Scrub Into The Lines. Use a grout brush or an old toothbrush to scrub the grout lines with firm, circular motions. Push the bristles into the joint itself. You should see dirt and mold release immediately. For stubborn stains, scrub for 30–60 seconds per line. Move to the next section once the grout appears visibly lighter.
6. Rinse Out All Residue. Use a clean cloth dampened with water to wipe away all cleaner residue. Go over each section twice to ensure no chemical remains on the tile or grout. If using bleach, rinse extra thoroughly. Spray with water if needed, but avoid flooding the bathroom. Wipe dry with a towel to prevent new mold from forming in wet grout.
7. Clean The Tile Faces. If the tile face itself has mold or staining, spray with the same cleaner and let sit for 5 minutes. Wipe with a damp cloth or soft sponge. Tile is non-porous and won't absorb mold the way grout does, so it's usually faster to clean. Avoid abrasive scrubbers on glazed or polished tile—they'll leave scratches.
8. Dry It Completely. Keep the exhaust fan or ventilation running for at least 30 minutes after you finish rinsing. Open the bathroom door and window. Don't take a hot shower for at least 2–3 hours, as moisture will undo your work. Grout needs to be bone-dry before mold can regrow.
9. Seal Against Moisture. Once grout is fully dry, apply a grout sealer using a small brush or the applicator bottle included with most sealers. Work carefully along each grout line, sealing both horizontal and vertical joints. Follow the product instructions for drying time—usually 48–72 hours before the bathroom is used heavily again. Sealer creates a water-repellent barrier that stops moisture from penetrating grout and starves mold of its environment.
10. Control The Humidity. After every shower, run the exhaust fan for at least 30 minutes. If your exhaust fan is weak or your bathroom stays humid, consider installing a more powerful unit or running a small dehumidifier. Cracking a window during and after showers also helps. The goal is to move moisture out of the bathroom rather than letting it settle on tile and grout.
11. Test And Reseal Annually. Grout sealer wears over time as cleaning, showering, and temperature changes take their toll. Once a year, do a water test: drip water on sealed grout. If it beads up, the sealer is still working. If it soaks in, it's time to reseal. Resealing takes 20 minutes and costs $15–30 per bathroom—cheap insurance against mold regrowth.