Prep first
Before you start
- Keep chlorine bleach away from rust. It sets the stain and makes it more intense.
- Remove any rusty object and blot up wet residue before anything dries.
- Work one small section at a time so the rust doesn't spread across the grout.
Rust stains on grout are iron that water or rusting metal has left in the lines between your tiles. Cement grout needs careful handling with acid, and a stain that has soaked in can become part of the grout itself. Epoxy grout lifts clean even after a stain has set, so find out which type you have before you pick a method.
Test the method on a small line of shower grout before you treat the whole wall. Harsh scrubbing roughens grout and gives the next stain more to grab, so keep to a soft brush. If rust stains on white grout keep coming back, iron is still getting in from the water, and that needs fixing before you scrub again.
Before you start
What grout can take
Safe to use4
- Water
- Hot water
- Enzyme cleaners
- Heat, once the stain is out
Use with care5
- Soaking
- Chlorine bleach
- Solvents (alcohol, spot removers)
- Acids (vinegar, lemon)
- Scrubbing and abrasives
8 items
What you'll need
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- Commercial rust removerThe acid that dissolves rust. Use it exactly as its label directs. (opens Amazon)
- Heavy-duty rubber glovesProtect your skin from the remover. (opens Amazon)
- White nylon padScrubs grout without scratching it, and nylon is the recommended tool. (opens Amazon)
- Soft nylon brushWorks the cleaner down into the grout lines. (opens Amazon)
- Mild cleaner made for tile and groutRemoves leftover residue without harsh chemistry. (opens Amazon)
- Mop or wet vacuumPicks up the dirty solution before it dries. (opens Amazon)
- Paper towels or white clothsBlot up residue without spreading it. (opens Amazon)
- Bucket of clean waterFor rinsing as you go and at the end.
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6 steps
Step by step
Step 1 of 61 minute
Clear the spill and blot
Take away any rusty object sitting on the grout, then wipe up the spill right away with a paper towel or white cloth. Blot wet residue instead of rubbing it across the lines, so the rust doesn't spread.
Step 2 of 6
Scrub with warm water
Wet the stained grout with warm water and scrub it with a white nylon pad for at least 60 seconds. Rinse with clean water and let the grout dry so you can see what's left.
Careful. Use only a white nylon pad, since abrasive cleaners can damage grout and greatly reduce sealer stain repellency.
Step 3 of 6About 2 minutes
Pretest the rust remover
Dampen a hidden patch of grout, apply a little of the rust remover, and leave it no longer than the label allows, 2 minutes at most. Rinse it off and check for any color change before you treat the stain.
Step 4 of 6
Apply the rust remover
Put on heavy-duty rubber gloves and apply the commercial rust remover to the stain only, following the label exactly, and don't leave it on longer than 2 minutes. Rinse thoroughly with clean water once it has done its work, and keep it off the tile around the grout.
Careful. Oxalic acid removers are poisonous and hydrofluoric acid removers are extremely corrosive to skin, so keep both away from children and bare skin.
Step 5 of 6A few minutes
Clean up any shadow left
If a shadow of the stain remains, apply a mild cleaner made for tile and grout and let it sit a few minutes without drying out. Agitate the grout with a soft nylon brush so the cleaner gets down into the lines.
Step 6 of 6
Lift the dirty solution
Pick up the dirty solution with a mop or wet vacuum before it dries, then rinse the grout with clean water. Let the area dry fully, then check the result.
Careful. Don't let cleaning solution dry on the surface, since leftover cleaner leaves a sticky film that attracts dirt.
If you'd rather buy than mix
Best products for rust on grout
Look for a commercial rust remover, and read its label before you buy, since strength and contact time differ between products. Pair it with a mild cleaner made for tile and grout.
RUST AID Bathroom Rust Remover
Zep Concentrated Calcium, Lime and Rust Stain Remover
How we picked these: each product is made for this type of stain, its maker doesn't warn against using it on grout, and its directions fit the steps above.
Finished the steps? How does it look?
Nice work. Let it dry completely and check it again in good light. Here is what done looks like:
How to tell it's really gone →A faint mark usually needs one more round, not a stronger product.
Heavy buildup usually takes more than one round.
Heavy or long-standing buildup →When to call a professional →How to tell it's working
Fresh rust often lightens after the warm-water scrub, and a clean rinse shows the true color of the grout. If the grout is still orange-brown once it has dried, the stain is set and needs the rust remover or a repeat of it.
What changes for yours
Adjust for your grout
Shower grout
Shower grout stays damp, so it looks darker and a rust stain can seem to come back after a rinse. Work one wall section at a time so you can pick up the solution before it dries, and rinse the walls well afterwards so no splashes dry on the tile face.
If the rust is on the tile face itself rather than the grout lines, the Tile guide covers that surface. Otherwise, repeat the rust-remover step on the stained section alone once the grout is dry.
White grout
White grout shows every mark, and a rust stain looks sharper against it, so check the result closely at each stage. Keep the pretest on a hidden patch and watch that patch for any change in color.
If the patch changes, stop and use the mild cleaner made for tile and grout on the stain instead. Rinse the white grout fully so no cleaner film dulls it.
Iron in shower water
Iron in household water leaves orange-brown marks on shower grout, and they tend to return after cleaning. Treat them with the same steps, but expect them to come back for as long as the water keeps carrying iron.
Rinse the walls and floor well after each treatment so no residue is left behind to catch more iron. If the rust keeps showing up in the same spots, the water is the real source to deal with.
Heavy or long-standing buildup
If the stain is old, it has usually soaked deeper into the grout, so one pass rarely finishes the job. Expect to run the whole sequence again, starting with the pretest, rather than scrubbing harder.
Stains that have dried and survived a first treatment respond better to a second pass with the rust remover, pretested again and rinsed well. Whether the grout is cement or epoxy also matters: stains become part of cement grout, while epoxy grout can usually be cleaned back to its original color.
If the stain still won't come out, pressurized steam can lift stains that don't respond to conventional cleaners. Be realistic about deep stains on cement grout, which may never fully disappear, and contact the grout maker's technical support before you try anything harsher.
Vinegar, baking soda, peroxide and more
Do home remedies work on rust on grout?
Many home remedies were written for fabric, laundry or limescale, and most don't belong on grout. Here's where each one stands for this stain, so you know what to leave out.
Helps1Skip4Avoid2
What makes it worse
Mistakes to avoid
Don't mix rust remover with bleach or ammonia
Bleach mixed with rust removers, vinegar or other acids can release toxic gas, and bleach with ammonia forms a toxic gas as well. Keep the bottles apart and rinse the grout well between products.
Don't use strong acid on grout
Strong acid solutions make grout lose its color or turn powdery or sandy, and they dull glazed tile. Stick to the rust remover at its label strength rather than mixing a stronger batch.
Don't leave rust remover on for more than 2 minutes
Acid rust removers should never sit longer than 2 minutes, and never where they can't be rinsed off thoroughly. Keep them off natural stone such as marble or granite and off painted, coated or sealed surfaces, since they can strip sealers and pit these materials.
Don't use oil- or wax-based cleaners on grout
They leave a film in the grout that holds dirt. Keep to a cleaner made for tile and grout.
Don't let rust remover touch porcelain or enamel
Rust removers can ruin porcelain and enamel finishes, such as a tub or a kitchen appliance. Mask off the tub and fixtures before you start, and keep a damp cloth close by for splashes.
When to call a professional
If the stain survives the steps and a repeat, or the affected area is large, a professional is the safer choice. Acid cleaning needs extreme care, and the grout maker's technical support can advise on the specific product you have.
Questions
What causes rust stains on grout?
Rust is iron oxide, and it usually comes from iron in household water or from rusty metal sitting on the grout. Once you know the source, deal with it, or the stain can keep coming back.
Can I make my own rust remover for grout?
It's better not to. Homemade acid mixes are hard to control, and acid can etch cement grout and strip its color. Use a commercial rust remover at label strength, pretested first, and rinse it well.
Is my grout epoxy or cement?
If you don't know, check any product information from the installer, and treat the grout as cement to be safe. Epoxy grout can usually be cleaned back to its original color, but stains become part of cement grout.
Will warm water alone remove rust from grout?
Warm water and a white nylon pad can lift fresh rust, so always start there. Set-in rust needs the commercial rust remover, pretested and used according to its label.
Is an orange water stain the same as rust?
Orange water stains are iron stains from the water, so they are rust stains and respond to the same steps. Pretest first, and expect them to return unless the water source is dealt with.
When should I call a professional?
Call one if a large area is affected or if the stain survives the steps and a repeat, since acid cleaning needs extreme care. Your grout maker's technical support can also advise on a specific product.
Rust on other materials
Other stains on grout
Start from the bigger picture
How we know this
Every method, amount and warning here comes from university extension services, industry bodies and product makers. We read them, check every step for unsafe combinations and changed amounts, and write it up so you can follow it.