To clean grout with hydrogen peroxide, mix 1/2 cup baking soda with 1/4 cup 3% hydrogen peroxide into a paste, spread it on the grout lines, wait 10–15 minutes, scrub with a stiff grout brush, and rinse with clean water. It lifts dirt and light mildew without the fumes of bleach and is safe on most ceramic and porcelain tile.
Why Use Hydrogen Peroxide on Grout?
- Oxygen bubbles loosen dirt deep in porous grout
- Brightens dingy grout and helps remove mildew stains
- No harsh chlorine fumes
- Cheap, and you likely have it at home
Best Grout Cleaning Mixes
| Mix | Recipe | Best for |
|---|---|---|
| Peroxide + baking soda paste | 1/2 cup baking soda + 1/4 cup 3% peroxide | Floor grout, general grime |
| Peroxide spray | 3% peroxide straight in a dark spray bottle | Shower grout, light mildew |
| Paste + dish soap | Paste above + 1 tsp dish soap | Kitchen grout with grease |
| Oxygen bleach | Powdered oxygen bleach + warm water | Heavy, old stains |
Do not mix hydrogen peroxide with vinegar in the same container; it forms peracetic acid, which irritates skin and lungs.
What You Need
- 3% hydrogen peroxide
- Baking soda
- Stiff grout brush or old toothbrush
- Bowl, spoon, and gloves
- Microfiber cloth or mop and a bucket of clean water
How to Clean Grout with Hydrogen Peroxide
- Sweep or vacuum the floor so loose grit doesn’t scratch the tile.
- Mix the paste to a toothpaste-like consistency.
- Apply it along the grout lines with a spoon or brush.
- Wait 10–15 minutes while it bubbles; keep it out of direct sun.
- Scrub along each line with a stiff brush.
- Rinse with clean water and wipe dry with a microfiber cloth.
- Repeat on stubborn spots, then seal the grout once fully dry.
Hydrogen Peroxide vs Bleach for Grout
Pros
- Low odor and safer around kids and pets
- Less likely to fade colored grout
- Breaks down into water and oxygen
Cons
- Slower on heavy black mold than bleach
- Can lighten colored grout with repeated use
- Loses strength months after the bottle is opened
Tips to Keep Grout Clean
- Seal grout every 1–2 years
- Run the bathroom fan after showers to reduce mildew
- Mop weekly with a pH-neutral cleaner
- Avoid acidic cleaners on natural stone like marble
For the rest of the room, see how to clean bathroom tiles and our move-in deep cleaning guide.
Frequently Asked Questions
Is hydrogen peroxide safe on all grout?
It is safe on most cement grout with ceramic or porcelain tile. Test colored grout in a hidden spot first, and test before using it near natural stone.
How long should hydrogen peroxide sit on grout?
About 10–15 minutes. Don’t let the paste dry completely before scrubbing.
Can I mix hydrogen peroxide and vinegar to clean grout?
No. Mixing them creates peracetic acid. Use them separately and rinse in between.
Does hydrogen peroxide kill mold on grout?
3% peroxide helps kill and lighten surface mold and mildew. Deep or recurring mold may mean the grout needs replacing.
Should I seal grout after cleaning?
Yes. Once the grout is fully dry (24 hours is safest), sealing helps it resist stains and moisture.
