How to Clean Grout

A person cleaning grout with hydrogen peroxide.

I live in an old apartment, where I’m lucky enough to have a ceramic tile bathroom floor. Of course, that also makes me unlucky enough to have grout in between those tiles. Unlucky because grout, the concrete-like substance used to adhere tiles to the floor and to fill the spaces between them, attracts dirt and is notoriously unpleasant to clean. If you’re trying to clean green, the difficulty is multiplied by the fact that most commercial grout cleaners are full of corrosive chemicals, and the most commonly recommended household alternative is chlorine bleach. Baking soda and vinegar are suggested fairly often for non-toxic grout cleaning, but I tried both and was disappointed. If your grout is lightly soiled, one of the two may work, but they simply didn’t have enough oomph for my grimy grout.

Finally, I discovered a lesser-known but far more effective solution: oxygen bleach. Despite the scary word “bleach,” oxygen bleach is absolutely safe for you and the environment. Hydrogen peroxide is one form of oxygen bleach, but it’s sold in such dilute concentrations (typically just 3% hydrogen peroxide and 97% water) that it probably won’t get your grout clean. Sodium percarbonate and sodium perborate, on the other hand, are usually sold as powders that can contain anywhere from 50% to 100% oxygen bleach. OxiClean is probably the easiest oxygen bleach to come by, but I found Biokleen’s more concentrated Oxygen Bleach Plus at my neighborhood food co-op. Good job, hippies.

Steps to Cleaning Tile Grout

  1. mixing the oxygen solutionFirst, mix the oxygen bleach solution in a bowl or bucket, according to the directions on the package. The brand I used called for 2-4 tablespoons of sodium percarbonate powder per 2 cups of water. I started with 10 cups of water, and that was way more than enough for my little bathroom floor. Just a heads up: oxygen bleach powder doesn’t dissolve instantly when it hits water, so you may need to do a little stirring and waiting until it’s all (or at least nearly all) in solution.
  2. pouring solution on groutNext, apply the oxygen bleach solution to the grout. I simply poured it onto the tile from a small measuring cup, then used my grout brush like a paintbrush to spread the pools of liquid over a larger area. If you want to deliver the oxygen bleach more directly to the grout, you might try using a turkey baster or an eyedropper. I recommend starting at the back of the room and working your way toward the door, always working with sections no larger than an arm’s length square.
  3. kitchen timerLet the oxygen bleach sit undisturbed on the grout for at least five minutes. If you watch closely during this time, you’ll see bubbles or white foam forming. This is the chemical reaction that enables oxygen bleach to lift stains, and the longer you allow it to work, the more dirt it’ll loosen. The reaction does eventually run its course, however, so if you want to give it more than 15 minutes, it’s a good idea to wipe the surface and apply fresh oxygen bleach.
  4. brushing the groutNow you can loosen the stains even further by scrubbing with a grout brush. An old toothbrush might also do a passable job, but a grout brush has much stiffer bristles and will be more effective.
  5. drying the groutAt this point, the floor is still wet and—if your grout is as grubby as mine was—pretty dirty. You should wipe away the moisture with a rag before the dirt gets a chance to resettle in your grout. If the rag gets saturated, just rinse it with plain water and squeeze it out before mopping up more liquid. After wiping the dirty oxygen bleach solution from the last section of your floor, wash or mop the floor with clean water to rinse.
  6. cleaned groutYou may not be able to see the final result of your work until the floor has been allowed to dry completely, since grout is porous and can appear darker when it’s wet. Once it dries, if you still think it can get cleaner, you may want to repeat the process to let the oxygen bleach lift even more dirt. The grout in my bathroom floor may get a bit lighter if I clean it again, but I suspect it was never actually bright white. Even no-traffic areas like under the radiator are the same light gray color as the post-oxygen-bleach picture you see to the left. As a person who has to walk barefoot on that floor, I can say I’m pretty impressed.

Grout Sealer

It’s possible that once you’ve cleaned your tile grout once, you won’t ever want to do it again. Even though, with this method, the oxygen bleach does most of the hard work, cleaning grout is always a little tedious and a little rough on your knees and back. So you may be thinking about applying a grout sealer or protector to keep the grout from getting dirty in the future. My advice? If you’re concerned about exposing yourself and the planet to hazardous chemicals, don’t.

Unless a cleaning product’s contents are beyond reproach, it’s usually tricky to find their ingredients listed anywhere. And the contents of grout sealer are not beyond reproach. Some varieties are certainly worse than others, but most are not as safe as the companies that sell them want you to think. Many manufacturers tout water-based formulas, but this does not mean they are completely free of harsh chemicals. A water-based grout sealer may nevertheless be flammable, irritating to the skin or lungs, or hazardous if it enters the water supply. If you’re absolutely opposed to cleaning grout again as long as you live, water-based grout sealers aren’t the most harmful products you can use in your home, but they aren’t natural by any measure.

Cleaning Grout Naturally

Spray bottle of Clean & GreenClean & Green Tile & Grout Cleaner uses a formula that the U.S. Environmental Protection Agency helped develop, so you know it’s easy on the environment. And, of course, it doesn’t pose any health risks, either..

Container of Oxy-GroutOxy-Grout is an oxygen bleach-based cleaner formulated especially for cleaning grout. It contains an (apparently secret) ingredient to speed up the reaction, so you don’t have to wait as long for the oxygen bleach to lift the stains.

Bottle of Hydroxi ProHydroxi Pro Grout Smart is a solution containing hydrogen peroxide and orange oil. This product is nice because you can use its concentrated formula for heavy-duty grout cleaning, and then dilute it when you need to do routine mopping. Also, the smell is nice. You can order HydrOxi Pro Grout from Amazon.

Pureclean Bath BlockEarthstone’s PureClean Bath Block is a scouring pad made from recycled glass. It combines awesome scrubbing power with a complete lack of chemicals, and can be used not only on grout but also on most of your bathroom fixtures.