How to Clean Grout Lines in Tile

Grout lines trap moisture, soap scum, and dirt faster than any other surface in your bathroom. They're porous by nature, which makes them functional but fragile—and cleaning them the wrong way can damage the grout itself or discolor your tile. The goal here is to restore clarity and brightness without using methods so aggressive they compromise the joint between your tiles. Done well, clean grout makes an entire bathroom look sharper, and it takes an afternoon, not a weekend.

1. Vacuum or dry-brush the lines first. Use a dry brush or the brush attachment on your vacuum to remove loose dirt, hair, and surface debris from the grout lines. This keeps you from turning dry dust into a paste that spreads around. Work in rows and don't skip this step—it makes the actual cleaning much more effective.
2. Mix baking soda paste for light to moderate buildup. Combine three parts baking soda with one part water in a bowl, stirring until you get a thick paste that clings to your brush without dripping. This is your first-line cleaner for everyday grime, soap scum, and mild discoloration. It's gentle enough not to etch or weaken the grout.
3. Apply paste and scrub with a stiff brush. Use a grout brush or old toothbrush to work the paste into the lines with firm, linear strokes along the grout joint. Don't scrub sideways across the tiles—you'll spread paste everywhere. Let the paste sit for 5 to 10 minutes to break down stains, then scrub again with a little more pressure. Work in sections so the paste doesn't dry out on you.
4. Rinse thoroughly with clean water. Use a damp sponge or cloth to wipe away all baking soda residue, then rinse with fresh water from a spray bottle or hose. Go over each line twice—baking soda left behind will lighten the grout's color and look dusty. Make sure the tiles are fully rinsed before moving on.
5. Use bleach solution for deep stains and discoloration. If baking soda didn't fully remove stains, mix one part household bleach with one part water in a spray bottle. Spray the affected lines, let sit for 5 to 10 minutes, then scrub with a stiff brush. This step is harsh—only use it on non-porous tile and grout you're certain can handle it. Never mix bleach with other cleaners.
6. Dry completely and inspect. After final rinsing, use a clean, dry towel to wipe the tile and grout lines. Let the entire area air-dry for at least 30 minutes. Walk through and check for missed spots, streaks, or residue. Any white haze left means there's still baking soda or mineral deposits; rinse again if needed.
7. Apply grout sealer if appropriate. Once everything is completely dry, consider applying a grout sealer (penetrating or membrane type, depending on your grout and tile). This prevents future staining and makes cleaning easier next time. Follow the product instructions—most cure in 48 to 72 hours before you can expose the grout to water. This step is optional but worth the $15 to $30 investment.