Scrub shower grout about once a month, and bathroom floor and wall grout every two to three months. Your weekly bathroom clean handles the surface; the monthly scrub gets into the joints before soap scum and mildew settle in. Shower grout that stays wet for hours, or a bathroom without a window, may need it every two weeks.
Grout gets dirty faster than tile because most of it is cement-based and porous. Marazzi's tile care instructions say grout darkens over time and needs periodic cleaning to remove surface buildup, even when it's sealed. What builds up is mostly soap scum, body oil, and mildew, which is why the bottom rows of the shower go first.
Grout cleaning schedule by location#
| Where |
Scrub the grout |
Notes |
| Shower floor and lower walls |
Monthly |
Squeegee after showers to stretch this |
| Upper shower walls |
Every 2 to 3 months |
Look for mildew near the ceiling |
| Bathroom floor |
Every 2 to 3 months |
Monthly near the toilet |
| Backsplash and dry wall tile |
Every 3 to 6 months |
Wipe splashes as they happen |
| Cement grout sealer |
Check yearly |
Reapply when water soaks in fast |
How to clean bathroom grout#
You'll need a stiff nylon grout brush (an old toothbrush works for small areas), a tile and grout cleaner that is safe for your tile, a bucket of clean water, and a towel.
- Sweep or vacuum the floor first, or rinse loose hair off the shower walls. Otherwise the brush just grinds grit into the joints.
- Wet the grout with warm water.
- Apply the cleaner and leave it for the time on the label. For routine cleaning, a household tile cleaner is enough. For heavy buildup, Marazzi recommends a professional-strength tile and grout cleaner made to remove soap scum, oils, and mildew stains.
- Scrub along each joint with short back-and-forth strokes. Work in sections a few feet wide so the cleaner doesn't dry on the wall.
- Rinse with clean water, changing it once it turns gray. Dirty rinse water just puts the grime back.
- Dry the floor or wall with a towel. Grout that dries fast stays cleaner longer.
For light grime, a paste of baking soda and water on the brush is a gentle option that won't hurt glazed tile or cement grout.
Skip the wire brush. It cleans by removing grout, and scraped grout is rougher, so it gets dirty faster afterward.
Is vinegar safe for grout?#
Not as a regular cleaner. Marazzi's care guide says acids can damage grout and glazed tile surfaces, and that ammonia can discolor grout. Cement grout is alkaline, and repeated vinegar scrubs slowly dissolve the surface and leave it rougher.
Natural stone is worse. Marble, limestone, and travertine react to mild acids, and Marazzi's guide says even a light vinegar-and-water solution will etch them. The etch is a dull mark in the stone, not a stain you can wash off, and it takes refinishing to remove. Stone showers need a pH-neutral cleaner made for stone, with no acid or bleach.
Mildew on grout: can you use bleach?#
You can, but you often don't need it. The EPA's mold cleanup advice for hard surfaces is to scrub with detergent and water and dry completely. Bleach can lighten surface stains on white grout, but test colored grout first because it can fade.
If you use bleach, use it on its own and rinse it off before any other cleaner touches the tile. Bleach plus an acid, which includes many limescale and bathroom cleaners, releases chlorine gas, as the Tennessee Poison Center explains. Run the fan with the door open while you work.
Is that grout, or is it caulk?#
The flexible line where the tub meets the wall, and usually the inside corners of the shower, is silicone caulk, not grout. Mold that has grown into silicone sits inside the material, so scrubbing won't reach it. If the black marks are still there after a clean, cut the old caulk out, let the joint dry for a day, and recaulk. The EPA specifically warns against caulking over moldy surfaces.
Should you seal bathroom grout?#
Cement grout, yes. Marazzi recommends sealing it with a penetrating sealer that doesn't contain silicone, and says you may need to reapply every year depending on the sealer, traffic, and how it's cleaned. Some sealers last several years, so follow your product's label. Epoxy grout is chemically cured and doesn't need sealing.
To check whether your grout needs it, drip some water on a joint. If it darkens within a minute or so, the water is soaking in and it's time to reseal. Sealing slows staining, but it won't stop buildup, so you still have to scrub.
When grout needs repair#
Cleaning won't help grout that's cracked, crumbling, or missing chunks. Water gets through those gaps into the wall or subfloor. Dark grout that stays dark when dry, tiles that move when pressed, or a soft spot in the wall usually mean water is getting behind the tile. Get that looked at before regrouting or recaulking over it.
Mildew that keeps coming back in the same corner is a ventilation problem as much as a cleaning one. Check that the bathroom exhaust fan actually clears the steam, and clean the shower curtain liner or glass doors on the same day, so the whole shower starts from clean. For the rest of the floor, see how to clean tile floors.
If you put the monthly shower scrub in ChoreLists.com as its own recurring task, it won't keep getting folded into a weekly clean that never quite reaches the grout.