How to Clean Grout: What Works, What Ruins It

Put the vinegar down. Seriously. Before we get into how to clean grout, I need to talk you out of the thing half the internet tells you to do first, which is pour vinegar on it and scrub. I’ve been cleaning floors around Baltimore County since 1998, and some of the worst grout I’ve ever seen was “clean” grout that somebody had been treating with vinegar every Saturday for five years. Crumbly. Pitted. Lines a sixteenth of an inch lower than the tile.

Grout Is Basically a Sponge

Most grout in houses around here is cement-based, basically sand and cement with some color mixed in. Looks solid. It isn’t, not really, it’s more like a hard sponge full of little holes, and those holes drink up whatever lands on them, mop water, apple juice, the stuff the dog brought in from the yard in March. So the dirt doesn’t sit on top where your mop can get it. It sinks. That’s why mopping on its own never fixes dirty grout, you’re kind of just giving it a grey drink every Saturday.

Your glazed tile, meanwhile, shrugs all that off. Which is how you end up with a nice clean tile floor framed by grout lines that look like they came out of a truck stop bathroom off I-83.

If yours has gone full black, not just grey, I wrote a whole thing about why grout turns black.

Vinegar Is Not Your Friend Here

Okay, back up on my soapbox. Vinegar’s an acid and cement grout is alkaline, and those two just don’t get along (basic chemistry, nothing fancy, but it matters here). Splash it once, no big deal. Do it every week for a couple years and it eats the top of the grout, the holes get bigger, the grout gets dirtier faster, so you use more vinegar. Fun little loop. Got marble or travertine? Then it’s worse, because vinegar etches the stone itself and leaves these dull cloudy patches that only a polishing machine brings back.

Bleach? Eh, Kind Of

People love bleach because the grout goes white in about four minutes, and yeah, it’s decent on mildew in a shower corner. Problem is the dirt’s still in there. You just dyed it lighter. On tan or grey grout you can end up with a blotchy, kind of camo look that’s worse than where you started. As a grout cleaner, bleach is mostly makeup, and if you do use it, rinse like you mean it.

And please, please don’t mix bleach with ammonia or with other cleaners. That makes toxic gas. The CDC has warnings about exactly this, and it’s not a theoretical thing. People end up in the ER from cleaning a bathroom with the door shut.

What I’d Actually Use at Home

Here’s the order I’d go in if I were doing my own kitchen on a Sunday and wanted the best way to clean grout without hurting anything. Gentle stuff first, and you only move up a round when the last one quits on you.

Hot water and a brush (yes, really)

Everybody who googles how to clean grout wants to jump straight to the chemicals. I get it. But hot water from the tap and a stiff nylon brush (nylon, not wire, I’ll come back to wire) gets more off than you’d guess. I do about a three-by-three patch at a time and then towel it up right away, because if that grey water dries in place it just goes back into the grout and you’ve basically scrubbed for nothing.

Then the baking soda

Didn’t do it? Okay. Grab the box of baking soda out of the fridge door (you were gonna replace it anyway) and add water till it’s about like toothpaste. Smear it on, go get a coffee, scrub when you’re back. It’s a little gritty so it does some of the work for you, it won’t hurt cement grout, and the box costs less than the coffee.

Oxygen bleach, my favorite

If I could only keep one DIY grout cleaner in the house, it’d be the oxygen bleach powder from the laundry aisle (sodium percarbonate, a dozen brands sell it). Dump a scoop in hot water and it fizzes like a science fair volcano, and that fizz is what lifts the food and dirt stains. Won’t wreck your colored grout the way the jug stuff does. Give it ten minutes, scrub, rinse twice because you’ll want to skip the second one, then dry it.

That’s pretty much how to clean grout at home without making it worse. Not glamorous. Your knees will complain.

Showers Are a Different Fight

Floors get dirt. Showers get soap scum, hard water and mildew, sometimes all three in the same corner. So how to clean grout in a shower is a little different from the kitchen.

That black or pinkish gunk down in the corners and along the bottom row of tile is mildew. And that’s the one place I’ll let you use watered-down bleach, fan on, door open, nothing else mixed in. Soap scum’s a different animal, and for that the oxygen bleach mix or plain dish soap in hot water does fine.

Two things that help more than any grout cleaner you can buy. Run the exhaust fan for twenty minutes after every shower. And keep a squeegee in there. Thirty seconds of squeegeeing the walls keeps dirty grout from ever getting started. Boring advice. Works anyway.

Stuff I’d Skip

• Magic erasers on grout (they shred and leave bits in the lines)
• Wire brushes, ever
• Steel wool, especially near any metal trim
• Colored grout pens over dirty grout, you’re just painting over dirt

Steamers, I go back and forth on. The little home ones loosen stuff up okay, then the dirt just sort of floats there in a puddle unless somebody’s right behind with a towel. Touch-ups, sure. Deep clean, nah.

When the Best Way to Clean Grout Is a Truck in the Driveway

There’s a point where you’ve done three rounds and the lines are still the color of a wet paper bag. That dirt is way down in the holes, and a brush isn’t reaching it, not yours, not mine. That’s where the truck earns its gas money.

Our version of how to clean grout is pretty simple to explain. We pre-treat with an alkaline grout cleaner made for the job, let it dwell, agitate the grout lines, then go over everything with a high-pressure tool hooked to the truck. Hot water blasts down into the pores and gets vacuumed straight back up in the same pass, so the dirty water doesn’t sit there and soak back in. Then we rinse, dry, and talk about sealing.

People are kind of shocked when they see the grout come back to its original color. “Oh, it was grey? I thought it was brown.” Happens on half the kitchens we do.

Keeping It Clean Between Deep Cleans

This one sounds backwards. Honest to God, most grout gets dirty from the mop. Picture your bucket by the third dunk, kind of grey, little bits floating in it, and now picture where all of that goes when you spread it across the floor. Right into the lines. Every week, like clockwork.

Long term, the best way to clean grout is to quit feeding it. I’d switch to a pH-neutral floor cleaner (the soapy ones leave film), dump the bucket way more often than feels reasonable, and ditch the string mop for a flat microfiber one, which holds a lot less dirty water. Sweep or vacuum before you mop, too. Otherwise you’re just making mud.

Stick with that and dirty grout turns into an every-couple-years thing instead of every spring.

Sealer, the Step Nobody Does

Nobody seals. I’d bet most of the kitchens I walk into haven’t seen sealer since the tile guy packed up. A penetrating sealer soaks into those little holes and makes the grout way less thirsty, so the spaghetti sauce beads up for a minute instead of diving in. Stain-proof? No. It just gives you a head start with the paper towel.

How often? Depends on traffic. Kitchen floors and showers, every year or two is reasonable. A guest bath, longer. Do a water drop test. If a drop of water darkens the grout in a few seconds, it’s time. If it sits on top, you’re fine. And if your grout is epoxy (newer showers sometimes are), it doesn’t really need sealing at all.

One thing, though, and I’ve watched people get this wrong. Seal it after it’s clean, because sealer over dirty grout locks that dirt in there for keeps.

A Few Local Notes

In Baltimore, a lot of rowhomes and older houses have those little white hex tiles in the bathroom with a ton of grout lines, and the grout’s often original or close to it. Be gentle with that stuff. And if it’s crumbling out when you touch it, no cleaning in the world fixes that, it’s time for somebody to regrout. When we do tile and grout cleaning Baltimore MD jobs in those houses, a lot of it is honestly just being careful with old material.

Up our way, it’s more big kitchen floors and mudrooms. Big tile, big grout lines, lots of foot traffic from the garage. Our tile and grout cleaning Cockeysville customers usually call because the path from the back door to the fridge is a different color than the rest of the floor. Classic. Nine times out of ten that’s mop water and grit, not a stain, and it comes right out.

And a lot of those same houses have hardwood running right up to the tile. Please don’t use your grout cleaning stuff on the wood. Different floor, different chemistry. If the wood’s looking dull, we handle hardwood floor cleaning Baltimore MD too, and we can usually do both rooms in one visit.

My Whole Take on How to Clean Grout, Short Version

If you skipped straight down here (no judgment, I would too), it goes brush, then baking soda, then oxygen bleach, with a towel after each one. Vinegar stays in the salad. Bleach is for shower mildew only. Seal when it’s clean. And if you did all of it and the lines still look rough, that’s not a you problem, the dirt’s just deeper than any brush reaches. Kind of the whole reason a guy like me has a job.

Extreme Carpet Cleaning LLC is still the same family outfit we started back in 1998, working out of the shop on Beaver Dam Road in Cockeysville. Our techs are IICRC certified, we run truck-mounted gear, and if our cleaning or repair work doesn’t hold up, the 150% money-back guarantee kicks in. We also do new carpet sales and carpet installation in Perry Hall and all over the county, and every install comes with a lifetime warranty.

Tired of scrubbing? Request a free quote or call (410) 666-6600 and tell us what your grout’s up against.