How to Clean Grout

Grout keeps ceramic tiles in place; it also keeps liquids, such as bath water that spills over the side of the tub, from penetrating the spaces around those tiles. It does the same for your bathtub, where it abuts the floor and walls, and sink (a.k.a. ‘caulk’). There are other applications for grout, but these are the ones you will be most familiar with in your home.

The grout around your tiles, and possibly around your tub and sink, is a mortar-like compound of water, sand, and cement. It dries quickly and becomes rock-hard. It usually comes in white, but it can be stained almost any color.

The other stuff that looks like grout and can even go over grout to seal out moisture is called caulk, or caulking compound. You can tell the difference between this and grout because it has the consistency of toothpaste when you apply it, and it never dries quite as hard as grout. It comes in either small tubes or in the form of long cartridge inserts that load into metal caulking guns.

In at least two ways it is similar to grout: black mold and mildew will grow on it, and you attack both of these problems the same way. These things aren’t just unsightly, they’re also a health risk. Best clean it off. There are several ways to do this:

How to Clean Grout

  • An Easy, Home-Made Grout Cleaner – The natural method also happens to be the cheapest. The last time we checked, a bottle of hydrogen peroxide cost about 88 cents. That and a spray bottle is all you need. Use half a cup of the stuff mixed with one cup of water. Put it in a spray bottle and spray it on the moldy areas. Don’t rinse. Some recommend a bleach solution rather than using hydrogen peroxide, but bleach is a major pollutant and it can turn your grout yellow so you might want to try the peroxide first. Spraying the grout with peroxide on a regular basis will also inhibit the mold from forming so consider keeping the bottle in your shower and spraying everything down periodically. Vinegar seems to have the same effect.
  • Clean Tile Grout with a Toothbrush – Unless dealt with regularly, mold can build up to the point where it needs to be attacked with a toothbrush and cleaning solution. Toothbrushes will not mar tile surfaces. If you’ve got a lot of work ahead of you, a high-speed electric toothbrush will make the work much easier.
  • Beware Harsh Chemicals – A number of environmentally-unfriendly commercial cleaners are touted to do the job, including Commercial Zep Mildew Stain Remover, X-14, and Limeaway. Never use these or other chemicals in combination, however, as poisonous gasses can result.
  • Pure Heresay – Perhaps the ultimate herbal approach to killing mold and mildew on grout is a solution of tea oil, an antifungal; mixed 2 tablespoons per 2 cups of water. Does it work? Try it and let us know using the form at the bottom of the page.
  • Stain it Some More – An alternative approach is to cover over the mold with a grout stain. This can be found at almost any home improvement store and will not fix your problem, only cover it up.

How to Prevent Grimy Grout

You will be cleaning mold and mildew less if your bathroom, kitchen, and anyplace else where tile combines with moisture, is equipped with an exhaust fan that takes the moisture out of the air.

How to Remove Grout

While you’re cleaning tile grout, take a careful look to assess how the stuff is holding up. If you see a lot of cracks and missing pieces, it may be time to replace it. Better to do it now before liquids seep through and start rotting out whatever is underneath the tile. Repairing is actually pretty easy. You only need a few inexpensive tools to remove the old stuff yourself. Grout remover kits can be found online and at most hardware stores.

Once you have gotten out all the loose old stuff, you can begin replacing the grout, tamping it in with your finger. If you have to cover large areas, it’s recommended to first mix the grout with latex additive to make it more waterproof.

Let the grout set for about three minutes, then go over it with a rubber float to force the grout deep into the joints. Follow up by wiping with a clean, damp sponge. The final touch is to add silicone caulk to the horizontal line between the top of the tub and first layer of tiles. Silicone is preferable to latex because it grips better and doesn’t come off as easily as latex caulking.

Finally, once the grout has been applied and allowed to cure, it should be sealed. Grout sealants prevent mold and dirt from penetrating into the grout or calking and make cleaning much easier.

When Grout Mildew Just Won’t Quit

If, after cleaning, the mold returns quickly, you may have more than just a surface mold problem. The mold may be embedded behind the tile and grout. You need to take a look, either by removing some tiles or cutting through an adjoining wall. Extensive mold is going to require some extensive work, so best call in a mold removal expert.

The same caution applies to caulk. If mold is building up with some frequency, inspect it for breaks – the mold could be coming from underneath, and the caulking should be removed.

There is another problem related to cleaning grout, particularly appropriate to those people who have children or have visiting friends or relatives who aren’t too bright. This is the problem of color stains on grout – such things as ink, crayons, hair dye, blood, etc. To clean crayon from grout, you can try using lighter fluid, turpentine, or mineral spirits, being careful not to inspect your work closely by the light of a lit match afterward. However, it would be safer, and probably more effective, just to chip out the damaged sections of grout and replace it with new – or use a grout stain to hide it.


  1. JackMan says:

    Seriously, this stuff is such a PITA to clean; once you’re done, make sure you seal it up good so you don’t have to do it all over again.

  2. Angie F. says:

    Kaboom Shower, Tub and Tile Cleaner works wonders on floor grout. I spray it on, and let it sit about five minutes. I use a grout brush I picked up at Target to scrub the grout line. I then use a wet rag to rinse. I keep a bucket of hot water next to me with the brush and a couple of rags in it. After I have done my kitchen, I reseal it with a silicone based sealant. I have cream colored grout and tile, and this is the most effective combo I have found. Work in small sections, and do not let the product dry on the grout.

  3. LLL says:

    Use a 3:1 ratio of baking soda and water to form a paste. Brush it into the grout and rinse. Repeat for stubborn stains.

  4. Elmo says:

    Drugstore hydrogen peroxide turns into harmless water quickly. Between dumping it in spray bottle – and probably keeping the nozzle open – and mixing it with water, it will be useless in a day or two.

    Tea oil, or tea tree oil? Tea tree oil is very useful for molds and has some a$$-kicking anti-bacterial properties, too. However, it’s not cheap. Some people like the smell. I hate it. Also, cat owners need to be very careful with natural oils. Natural does not mean harmless.

  5. JerryP says:

    Grain alcohol is great to kill mold and mildew although it can’t be gotten in all states. It’s either 175 proof or 190 proof. You can spray it on, but beware the effects of breathing the fumes and whatever you do, don’t light a match until it has evaporated.

  6. PB&AJ says:

    Bleach has not worked at all on my grout, neither has commercial grout cleaner. I’m trying baking soda, peroxide, and then vinegar, in that order. If that doesn’t work, I’m throwing a hand-grenade in there and ducking for cover. We just moved in and I have NO idea how long it’s been since it was cleaned and I’m sure the maintenance people have NO clue what grout sealer is since they didn’t even install the tiles correctly!

  7. Bernadette says:

    CLEANING GROUT: Easy off oven and grill cleaner for grout with years of buildup; vinegar works on the easy jobs…I have tried everything; let it sit at least one half hour. Use an electric toothbrush. It’s still time consuming, but it works. I also used a clothing steamer first with a towel wrapped around the end in one location with grout that seemed to be mixed with caulk-like material.

  8. Deena says:

    CLEANING GROUT: Keep a Clorox bleach pen in the shower and before you are done showering, go over the lines of the grout with the pen once a week and your grout stays white!

  9. Alan says:

    Tile and grout cleaning is a difficult and labor intensive task. Typically, the problems arise within the grout and the exterior because both accumulate soap scum or other materials. By hand, to clean this surface effectively, it requires the right cleaners and a lot of scrubbing. The good news is that Daimer Industries have developed steam cleaners that take all of the work out of tile and grout cleaning. We have a wide variety of products to help with this task including portable steamers, pressurized vapor cleaners, and other tile cleaning equipment.

  10. Vie says:

    A cup of borax and 2 cups of water mixing together in a sprayer will do the trick, especially for the grout on the floor. Spray the mixture and leave it for 15-25 minutes and dry it with a towel or paper towel; viola, you have a nice, clean and disinfected grout. For the stubborn stains, spray the mixture in the affected area, leave it for 5-10 minutes and then brush it hard and dry it with the towel. Thank you.

  11. Ciel says:

    I am using the Sonic scrubber instead of my electric toothbrush and the results so far have been far better than before. But, the brush tips come with NO instructions as to which to use where and today (second use), I am having some trouble changing heads. Could be just the one I am using, the head, or my hands today. But, try it yourself.

  12. Jen says:

    Tea tree oil is a fantastic anti-fungal, bacterial, etc. Again, you do need to be careful of how concentrated you use it as it can cause irritation, etc. (i.e use gloves).

    It is also an “oil,” i.e it does not dissolve in water. I would suggest mixing the tea tree oil with a small amount of dish washing liquid and then adding the water; the dish washing liquid will allow it to mix evenly throughout the water. After, you can then just use some hot soapy water to wipe away the excess.

  13. Nat says:

    Mineral turpentine works great, but you need about two scrubbing brushes and two toothbrushes because all that scum lifts off onto the brushes, etc., and you CAN’T get it off. I just too them after that. I figured this out after I used turps to get blue tack off a wall and thought if it can get that off then what can it do to soap scum and mold. It kicks butt!!

  14. SIJS says:

    The answer… A product called “Kaboom” cleans the hard to clean mineral deposits and grime off shower glass if you follow their instructions. It is hard to find however you can go on line and find where they sell it or order it on line. It works exceedingly well and I believe it has pumas in it, much like “Lava” soap for cleaning and dissolving grease and hard grime off your hands, which perhaps could be used too or other products as such, with a toothbrush and some elbow grease however, Kaboom works well on the glass with little effort. Too, you should know that when they build wealthy homes, they usually coat the grout within the showers with a special, clear substance that literally keeps the grout looking beautiful for 15-20 or even more years before you have to reapply it again. Purchased at almost any home improvement store, they can show you where it is and the various options, all lasting different lengths of time and costing different amounts with the 20 year one around $60.00 dollars I believe or perhaps less. Go for the really long lasting one. One large container will do more than one bathroom and you could even split the cost with a friend, neighbor, or relative for their home as well. You also can purchase either online or at Bed Bath and Beyond type of establishments a good steamer for clothes and grease areas that has all kinds of attachments and apply really hot steam to the grout like the professionals would come in and do for you for cleaning it. Once you have it clean and very dry, apply the barrier mentioned above and you will have nipped this problematic situation in the bud for many, and I do mean, many years. Sincerely, S

  15. SIJS says:

    I forgot to tell you, “to keep the glass inside of your shower cleaner,” once clean and dry, it perhaps would be
    worth it to try applying “Rain-X” on the inside according to the directions, just like you would on your car
    windshield so that the glass would then tend to repel water off of it. I know when “applied properly” on your car
    windows, it works well. I do know that if you use liquid bath soap instead of bar soap, you have far less residue
    on glass and tubs left behind as well. You perhaps would have to apply the Rain-X twice a month. I have not
    done this one, but it may work as well as it does on car glass. Sincerely, S.

  16. John P. says:

    The title paragraph has a couple of misconceptions.

    Grout is not impervious to water. Water can weep through grout. That is why a barrier (Kerdi, Red Guard, etc.) that IS impervious to water is applied to the substrate, and the tile is adhered to that. Also,
    grout does not keep tiles in place. That is the job of the tile adhesive, such as Thinset. Grout just fills in the spaces between the tiles.

  17. Lynn says:

    Just used baking powder and a toothbrush, and all my orange grout is now whitish.


  18. Mommy truth says:

    After using your cleaner of choice, then a battery-operated scrub brush, scrub the grout with a Mr. Clean Magic Eraser. The Magic Eraser also works on shower doors along with your cleaner of choice!

  19. Arnold says:

    Hydrogen peroxide works pretty good as a natural cleaner. Another great natural cleaner is vinegar and baking soda. Both of these items mixed together help to create an oxidizing effect that helps to get rid of tough stains. Baking soda or vinegar only do not work nearly as well.

  20. Wayne says:

    Bleach is a good starting point for cleaning the grout, but if all else fails, the one tip that always works and is a tiler’s best kept secret, is a product called “Aqua Mix Grout Colorant.” You apply it to the surface of the grout, leave it a while and then clean off the excess with a scouring pad, leaving behind an epoxy coating color. You can even change the color of grout using this stuff. Tilers tend to keep it in their vans to deal with efflorescence issues and other grout anomalies. If you want to re-grout, then rake out a couple of millimeters and then cap the grout; it will then have a key to the existing grout. I’ve done my fair share over the years. :-)

  21. Peter says:

    An excellent way to remove mold from tiles is using a CS (colloidal silver) solution.
    Rinse the tiles with a baking soda solution and wash. Afterwards, spray on a CS solution. This will penetrate the grout and kill the mold for a very long time!
    For a new application of grout, mix the grout not with water, but with a water/CS mixture and the grout will stay clean for many years.
    Regarding caulk: in most cases, the caulk is applied without sterilizing the area of application and mold will grow under the caulk. This mold (Anaerobic bacteria) cannot be removed without taking away the caulk! In case of new caulking, rinse the area with water, apply CS (spray), dry, and than apply the new caulk; no mold can grow on such a sterilized surface!

  22. Sandy says:

    I agree with Arnold (2012); baking soda and vinegar worked WONDERFULLY! Now, to seal it. I also like the Rain-X idea on a shower door. Hmmm. :0

  23. Vanessa says:

    Sandy, How much baking soda do I use and how much vinegar? Also, how long do you think I can let the solution stay before I start the painful scrubbing, like a couple of hours or just minutes? The apartments finally came and recaulked around the tub so now I just want to get the tiles and grout clean so I can feel normal while taking a shower instead of really gross, lol, it is already hard enough because of my hair that comes out in the shower and touches me, lol, a little OCD about things like that. Thanks for your help.

  24. Help!!! says:

    I have used everything and scrubbed and scrubbed. It’s a pretty old house, so it’s been like this for a long time!

  25. Dawn says:

    I have tried peroxide and also a paste mix, but the only thing I have found to clean my grout is straight up vinegar. I got a short hard bristle brush (XO from Target) and it makes a good scrub brush. I let the vinegar set for five minutes, scrubbed and then rinsed. The smell is not good, but the results are!

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