How to Clean Grout and Keep It White

Dirty grout is almost always a surface problem, not a permanent one. With the right cleaner and a few minutes of dwell time, most grout goes back to white (or close to it) without any professional help.

The catch is that different grout types and different levels of buildup call for different approaches. Using the wrong cleaner on the wrong surface can etch stone, bleach colored grout, or just waste your time.

What You're Actually Cleaning

Grout picks up two kinds of grime, and they respond to different treatments.

Soap scum and mineral deposits are what turn white grout gray in showers. These are alkaline or neutral deposits, so you need an acid to cut them. Mild acids like diluted white vinegar or citric acid work well here. Just note: if your tile is natural stone (marble, travertine, slate), vinegar will etch the surface. Use a pH-neutral stone cleaner instead.

Mold and mildew show up as black or pink spots, mostly in wet areas like showers and tub surrounds. These need an oxidizing agent to kill the spores, not just scrub them away. Oxygen bleach (sodium percarbonate) or diluted chlorine bleach are the go-to options. If you see recurring mold in the same spot, there may be a moisture issue behind the wall worth investigating.

Body oils and general grime in floor grout respond well to alkaline cleaners: dish soap, baking soda paste, or a diluted all-purpose cleaner.

DIY Grout Cleaner Recipes by Soil Type

These are the formulas I keep coming back to. Measurements matter more than people think: too diluted and nothing happens, too concentrated and you risk damaging the grout or the tile surface.

For soap scum and hard water buildup

Mix 1 part white vinegar with 1 part warm water in a spray bottle. Spray the grout lines and let it sit for 5–10 minutes. Scrub with a stiff-bristled grout brush, then rinse. For stubborn mineral buildup, undiluted white vinegar applied with an old toothbrush and left for 15 minutes cuts through faster.

Do not use this on: natural stone tile, epoxy grout, colored or dyed grout (the acid can fade pigment over time with repeated use).

For hard water stains that vinegar can't touch, see how to get rid of hard water stains in the bathroom. The citric acid soak covered there works on grout too.

For mold and mildew

Mix 3/4 cup oxygen bleach powder (like OxiClean, though any sodium percarbonate product works) with 1 gallon of warm water. Apply to the grout, let it dwell for 20–30 minutes, scrub, and rinse. This is safer for colored grout and natural stone surrounds than chlorine bleach.

For heavy mold, chlorine bleach diluted 1:10 with water (roughly 1/4 cup bleach per 2.5 cups water) applied directly to grout lines and left for 10 minutes is more aggressive. Rinse well, keep the bathroom ventilated, and never mix this with any ammonia-based cleaner. Chlorine bleach plus ammonia creates toxic chloramine gas.

Critical: If mold keeps returning within a few weeks of cleaning, read up on how to remove bathroom mold and mildew safely before treating again. Recurring mold usually means the surface treatment isn't enough.

For floor grout and general grime

Make a paste: 3 parts baking soda to 1 part dish soap (about 3 tablespoons baking soda + 1 tablespoon dish soap). Apply to grout lines, let sit for 5 minutes, scrub, and rinse. This is mild enough for any grout type, including colored and epoxy grout, and it won't touch natural stone negatively.

Step-by-Step: Cleaning Shower Grout

Shower grout takes the most abuse, so it helps to work methodically.

1. Ventilate the space. Open the window or run the exhaust fan. This matters even for oxygen bleach; you don't want to be breathing cleaning solution fumes in a tight shower.
2. Rinse the walls with hot water. This softens deposits and helps the cleaner penetrate rather than bead off.
3. Apply your cleaner to dry or damp grout (not soaking wet, or you're just diluting it). Work from top to bottom so drips hit untreated areas.
4. Set a timer for the dwell time. The cleaner needs time to do its job. Wiping it off at 30 seconds is a common mistake.
5. Scrub with a stiff-bristled brush. A dedicated grout brush or an old electric toothbrush head gets into the grout line without scratching tile. Avoid steel wool or wire brushes on any finished surface.
6. Rinse thoroughly with warm water, starting from the top. Leftover cleaner residue attracts new grime faster.
7. Dry the surface with a towel or squeegee. Don't leave standing water in the grout lines. That's how mold starts.

For glass shower doors with water spots, the cleaning guide for glass shower doors has a compatible routine you can run at the same time.

How to Keep Grout White After Cleaning

Cleaning grout is satisfying. Watching it get gray again in six weeks is not. These habits make a real difference.

Seal it. Unsealed grout is porous and stains almost immediately. After a deep clean, apply a penetrating grout sealer (a foam applicator brush makes this easy). Most sealers need to be reapplied once a year in showers, every 2–3 years on floors. You can test whether your grout is sealed by dripping a few drops of water on it. If the water beads, you're fine; if it soaks in within a minute, reseal.

Squeegee after every shower. Takes 20 seconds. Removes the standing water that feeds mold and deposits mineral residue. This one habit extends cleaning intervals significantly.

Weekly spray. A light mist of diluted white vinegar (1:1 with water) on shower walls and grout after your last shower of the week, no scrubbing needed, slows soap scum accumulation. Skip this on natural stone.

Fix the ventilation. If the bathroom fan isn't pulling enough air out, no amount of cleaning will keep mold away. The fan should run during showers and for 20–30 minutes after.

Grout Types and What They Can Handle

Grout type	Can use bleach?	Can use vinegar?	Can use baking soda?	Notes
Cement (sanded/unsanded)	Yes, diluted	Yes, diluted	Yes	Most common; needs sealing
Epoxy grout	No (can discolor)	No (can break down)	Yes	Very stain-resistant; rarely needs deep cleaning
Colored/pigmented grout	Use carefully	Use sparingly	Yes	Acids and bleach can fade color over time
Natural stone tile grout	Yes, diluted	No (etches stone)	Yes	Stick to pH-neutral or alkaline cleaners

Frequently Asked Questions

How often should I clean grout in the shower?

A light cleaning every 2–4 weeks keeps buildup from getting ahead of you. If you squeegee after every shower, you can stretch that to monthly. Deep cleaning (oxygen bleach or diluted chlorine bleach for mold) is usually a once or twice a year job if you're maintaining regularly.

Why does my grout turn yellow instead of gray?

Yellow tinting usually comes from one of three things: hard water iron deposits, certain cleaning products (especially some pine-based cleaners) reacting with the grout, or cigarette smoke residue. An oxygen bleach soak handles the first two. Iron-specific stain removers (oxalic acid based) work for stubborn rust-yellow spots, but test in an inconspicuous area first.

Can I use a steam cleaner on grout?

Yes, and it works well on cement grout. The heat and pressure loosens grime without any chemicals. Keep the steam head moving; holding it in one spot on ceramic tile for too long can crack the glaze. Avoid steam on epoxy grout; repeated high heat can soften the binder over time.

My grout is clean but still looks dark. What's happening?

If the grout looks clean when wet but darkens when dry, the grout may be permanently stained (often from oils that have polymerized into the surface). At that point, sealing won't help. You'd need to either regrout or use a grout colorant/paint product designed for this. These are trickier to apply evenly but work reasonably well on straight grout lines.

Is it worth hiring someone to clean grout professionally?

If you've got a large tiled shower that's been neglected for years, or floor grout that's deeply ground-in, a professional with a rotary brush and a truck-mounted extractor can get results a brush and bucket can't match. For regular maintenance though, the DIY recipes above are genuinely sufficient. You don't need professional cleaning more than once every few years, if that.