You scrub the tiles until they shine, but the floor still looks dingy. The culprit? It’s usually the grout. Many homeowners are shocked to discover their “gray” grout lines were actually white all along.
Grout is porous, meaning it soaks up dirt, grease, and grime like a sponge. If you want to restore your floors and banish mold, we have the solutions.
We have compiled nine effective methods to clean floor grout, ranging from natural DIY pastes to heavy-duty steam cleaning. Here is how to make those lines pop again.
Key Takeaways
- Grout is porous and absorbs spills, making it a breeding ground for bacteria and mold.
- White grout can handle bleaching agents, while colored grout requires milder, non-bleach solutions to prevent fading.
- Always identify if your grout is sealed or unsealed; acidic cleaners like vinegar can damage unsealed cement over time.
- Top cleaning methods include hydrogen peroxide pastes, oxygenated bleach, steam cleaners, and specialized alkaline cleaners.
Why Grout Gets So Dirty
Grout is essentially a mixture of sand and cement. Because of this composition, it is highly porous. It absorbs dirt, grease, and liquid spills, which eventually stain the lines and make your entire floor look discolored and neglected.
In high-moisture areas like bathroom floors, grout becomes a hotel for mold spores. Dark, damp spots around the toilet, behind the sink, or in the shower are prime real estate for mold (1).
Cleaning these lines improves the look of your home and eliminates potential health hazards.
Colored vs. White Grout
Your cleaning strategy must match the color of your grout. Using the wrong chemical on colored grout can ruin the dye.
1. Colored Grout
Avoid chlorine bleach on colored grout. It will pull the color out, leaving you with patchy, uneven lines. It can also damage natural stone tiles.
Some home remedies suggest hydrogen peroxide. While effective, it acts as a mild bleach. It can still dull the color of your grout over time, so use it with caution.
Your best bet is a pH-neutral commercial cleaner or an alkaline cleaner designed for colored grout. If the grout is permanently stained, you might skip cleaning and go straight to a Grout Pen. These pens paint over the line to restore the original color.
Do A Test
2. White Grout
White grout shows every speck of dirt, but it is also more forgiving with harsh cleaners. You can use bleaching agents to brighten it back to its original state.
Hydrogen peroxide is excellent here. For a natural approach, a 50/50 mix of white vinegar and water works well on sealed grout, though you should limit vinegar use on unsealed cementitious grout to avoid erosion.
Sealed vs. Unsealed Grout
Most grout is cement-based and porous, so it usually requires a sealant. Knowing if yours is sealed changes how you clean it.
1. Sealed Grout
A sealer acts as a protective shield, filling the “pores” so liquids cannot penetrate.
Cleaning sealed grout is much easier because the dirt sits on the surface rather than deep inside. If you are deep cleaning your tiles, a quick mop might be enough.
You can generally use mild acidic cleaners (like diluted vinegar) on sealed grout, but rinse it quickly. If the sealant is worn down, acid can eat away at the grout beneath.
Note: If you have natural stone tiles (marble, travertine, slate), never use vinegar or acid. It will etch the stone permanently.
2. Unsealed Grout
If your grout absorbs water immediately, it is unsealed.
Standard cement grout should be sealed. If it isn’t, it will stain rapidly. However, epoxy grout is the exception. Epoxy contains resin rather than just cement and sand, making it waterproof and stain-resistant without a sealer.
To clean epoxy grout, you can use a mix of bleach and water or vinegar and water (2). For unsealed cement grout, avoid heavy acids and stick to alkaline cleaners or oxygen bleach.
Best Tools to Clean Grout
Elbow grease is often the main ingredient, but the right tools save you time. Here are the best weapons for your arsenal:
- Grout Brush: These have stiff nylon bristles cut in a narrow V-shape or line to fit perfectly inside the grout joint.
- Drill Brush Attachment: This is a game-changer. It is a round nylon brush that attaches to your power drill. It does the scrubbing for you at high speed.
- Old Toothbrush: Perfect for tight corners or small spills. An electric toothbrush works even better.
- Steam Cleaner: The ultimate tool for sanitizing. It uses high-heat steam to blast dirt out of the pores without chemicals.
How to Clean Floor Grout: 9 Methods
From pantry staples to heavy-duty chemicals, here are nine ways to tackle dirty grout.
Hydrogen Peroxide, Baking Soda, and Dish Soap
This is the “DIY Gold Standard” for grout. It combines abrasion, lifting power, and mild bleaching.
The Recipe:
Mix 3/4 cup baking soda, 1/4 cup hydrogen peroxide, and 1 tablespoon of dish soap.
The baking soda acts as a gentle scrubber (3), while the hydrogen peroxide releases oxygen ions to break down stains (4). The dish soap cuts through surface grease.
Apply the paste with a brush. You might see some bubbling, which is a good sign. Let it sit for 15 minutes, then scrub thoroughly. Rinse with hot water and wipe dry.
Save Your Back
Oxygenated Bleach
If you want the whitening power of bleach without the toxic fumes, use oxygenated bleach (sodium percarbonate). It is safer for the environment and highly effective on organic stains.
Oxygen bleach usually comes as a powder. When mixed with water, it creates oxygen bubbles that lift dirt from the grout pores (5).
Dissolve two tablespoons of oxygen bleach powder into two cups of warm water. Mix it fresh, as it loses potency after a few hours.
Pour the solution onto the grout lines. Let it soak for 10 to 15 minutes. This dwell time is critical. Scrub with a nylon brush, then rinse well. For tough spots, dip your wet brush directly into the powder for extra grit.
Steam Cleaner
Cleaning grout with steam is the chemical-free option. It relies on heat (over 200°F) to kill bacteria, mold, and loosen deep-set grime (6).
Attach the grout nozzle (usually a small, stiff brush) to your steamer. Apply steam directly to the grout line while scrubbing back and forth. Wipe the loosened sludge immediately with a microfiber cloth before it dries back onto the tile.
Steam is safe for most sealed and unsealed grout, but double-check your tile manufacturer’s guidelines.
Alkaline Grout Cleaner
Sometimes DIY mixes aren’t enough. Commercial “alkaline” cleaners are formulated with a high pH to dissolve fats, grease, and general soil. They are generally safer for tile than acidic cleaners.
Look for products labeled specifically as “Grout and Tile Cleaner” or “Degreaser.” Follow the bottle instructions, apply, let it dwell, scrub, and rinse. These are great for kitchen floors where grease buildup is the main issue.
Chlorine Bleach
Chlorine bleach is a potent disinfectant and whitener, making it effective for killing mold (7). However, it is harsh. It can damage clothes, irritate lungs, and erode grout if used too often.
Safety First: Open windows and turn on fans. Wear gloves, safety glasses, and old clothes (8).
Dip a brush into undiluted bleach (or a 50/50 water mix) and scrub the stained area. Rinse thoroughly with clean water to remove all chemical residue.
Warning: Do not use this on colored grout or natural stone.
Ammonia
Ammonia is excellent for cutting through grime and killing mildew.
Mix equal parts ammonia and water. Scrub the grout vigorously, then rinse well.
Danger
Warm Water and a Stiff Brush
For maintenance cleaning or slightly dirty floors, keep it simple. Hot water loosens dirt, and a stiff brush does the rest.
Pour hot water on the lines, scrub immediately, and dry with a towel. This prevents soap scum buildup from cleaning products.
Homemade Grout Cleaners (Use with Caution)
Baking Soda and Vinegar
This classic science experiment combo creates a bubbling reaction that can help lift dirt.
Make a paste with baking soda and water. Apply it to the grout lines. Spray a solution of vinegar and water over the paste. Once the fizzing stops, scrub with a brush and rinse.
The Risk: Vinegar is acidic. While it cleans well, frequent use on cement-based grout can weaken the cement over time. The Tile Council of America advises against using vinegar on unsealed alkaline-based grout (10).
Stone Warning
Lemon Juice
Like vinegar, lemon juice is acidic and works to break down grime and bleach stains naturally.
Saturate the grout with lemon juice, let it sit for 10 minutes, scrub, and rinse. Only use this on ceramic or porcelain tiles, never on natural stone.
Final Tips for Maintenance
Keeping grout clean prevents the need for intense scrubbing sessions later.
- Clean spills ASAP: Coffee, wine, and juice can penetrate sealed grout if left too long. Wipe them up immediately.
- Use a wand: Save your knees. Buy a grout brush with a long, extendable handle so you can scrub while standing up.
- Avoid metal tools: Steel wool and wire brushes are too harsh. They can scratch your tile and strip the grout away. Stick to nylon brushes.
- Seal your grout: This is the best defense. Apply a penetrating grout sealer once a year. You can use a spray-on sealer or a brush-on applicator bottle.
- Cheat with a pen: If the stains won’t budge, buy a Grout Pen. It is essentially paint for your grout and makes the floor look brand new instantly. For white grout, the Clorox Bleach Pen is also a handy tool.
FAQs
How Can You Tell If Grout is Sealed?
Place a few drops of water on the dry grout. If the water beads up and sits on the surface, it is sealed. If the water darkens the grout and soaks in immediately, it is unsealed and needs a fresh coat of sealer.
How Often Do You Need to Seal Grout?
You should reseal grout every 12 to 18 months, or whenever the “water test” shows absorption. High-traffic areas like entryways and shower floors may need sealing more frequently than guest bedrooms.
Does Magic Eraser Clean Grout?
Yes, melamine sponges like the Mr. Clean Magic Eraser are abrasive and effective at scrubbing surface dirt and scuffs from grout lines, though they may shred quickly on rough sanded grout.
Can You Use Toilet Bowl Cleaner on Grout?
While popular on social media, using toilet bowl cleaner is risky. These cleaners are highly acidic and contain harsh chemicals that can strip grout sealer, eat away at the cement, and damage stainless steel appliances nearby. It is safer to use an oxygen bleach paste.
Does Vinegar Ruin Grout?
Vinegar can ruin grout over time. Because grout is alkaline (cement-based) and vinegar is acidic, frequent use can chemically dissolve the cement, causing the grout to crumble or crack. It is best to use vinegar sparingly or stick to pH-neutral cleaners for regular maintenance.
