Grout starts out white or light grey, then a few years of foot traffic, spills, and mopping with the wrong products turns it grey, blotchy, or black in the lines between your tiles. If you have ever scrubbed a bathroom floor with a toothbrush and barely made a dent, you already know cleaning grout tiles is nothing like wiping down a benchtop.
The good news is that most household grout can be brought back to something close to its original colour without hiring a professional, provided you use the right approach. This guide walks you through how to clean grout using tools and products you likely already have, plus a few tricks that make the job faster and easier on your knees.
We cover the step-by-step method for tackling stained grout lines, when a store-bought cleaner beats a homemade paste, and how to protect your work with sealant so the grime does not creep straight back in. If your grout is too far gone for a weekend DIY fix, we will also explain when it makes more sense to call in professional tile and grout cleaning services instead of wearing out another scrubbing brush.
What you’ll need before you start
Gathering everything before you kneel down on the bathroom floor saves you from tracking dirty water across the house halfway through the job. Grout is porous, so the right combination of tools matters more than brand names, and most of what you need is already under the kitchen sink or in the laundry cupboard.
Tools and products checklist
Start with the basics and add a store-bought grout cleaner only if your stains are old or your grout has gone dark grey to black. A stiff-bristled brush designed for grout does the heavy lifting far better than an old toothbrush, and a spray bottle lets you apply solution evenly without soaking the whole floor.
| Item | Purpose |
|---|---|
| Broom or vacuum | Remove loose dirt and grit before wetting the floor |
| Bucket of warm water | Rinsing and diluting cleaning solutions |
| Spray bottle | Even application of cleaner onto grout lines |
| Grout brush or stiff nylon brush | Scrubbing without damaging tile glaze |
| Bicarbonate of soda | Base ingredient for a homemade paste |
| White vinegar or oxygen bleach | Cutting through grease and mould stains |
| Old towels or a mop | Drying tiles after rinsing |
| Grout sealer | Protecting clean grout from future staining |
| Rubber gloves and eye protection | Skin and eye safety when using acidic or bleach-based products |
Ten minutes spent gathering the right gear saves an hour of stopping mid-scrub to search the cupboard for something that actually works.
Safety precautions worth taking
Remember that oxygen bleach and vinegar should never be mixed with chlorine bleach, since the combination produces toxic fumes in an enclosed bathroom. Open a window or turn on the extractor fan before you start, and keep pets and kids out of the room while you work. Rubber gloves protect your hands from the drying effect of bicarbonate soda pastes and the acidity of vinegar-based cleaners, and safety glasses are worth wearing if you are spraying anything overhead on wall tiles.
Testing a small hidden patch of grout with your chosen cleaner first is a habit worth building, particularly on coloured or older grout that may react differently to acids than the white grout most guides assume you have. Once you know your gear is ready and your bathroom or kitchen is ventilated, you are set to move on to the actual cleaning process.
Step 1. Sweep and rinse the tiles
Begin by clearing every bit of loose grit, hair, and dust from the floor with a broom or vacuum, working right into the corners where debris likes to hide. Skipping this step means you will grind sand and grit straight into the grout lines the moment you start scrubbing, turning fine particles into tiny scratches on the tile glaze. Loose debris removal takes two minutes and saves you from undoing your own hard work before you have even reached for a cleaning solution.
Once the floor is free of grit, rinse the whole area with warm water using a mop or a damp cloth. This first rinse softens any surface grime and gives you a clearer look at exactly which grout lines are genuinely stained versus just dusty, which helps you decide how strong a cleaner you actually need for step two.
A quick sweep and rinse before you touch a single cleaning product is what separates a smooth job from a scratched, muddy mess.
Dampening the tiles first also stops porous, unsealed grout from soaking up your cleaning solution too fast, which would leave the surface dry and patchy before you have had a chance to scrub it in properly. Kitchens and laundries often need an extra pass here, since cooking grease and detergent residue settle into grout lines and resist a plain water rinse, which is why kitchen floor grout usually takes more work than a bathroom. Give those areas a second go with warm water and a splash of dish soap if the first rinse still leaves the water looking cloudy. With the tiles clean of loose dirt and evenly damp, you are ready to bring in the grout cleaning solution itself.
Step 2. Apply a grout cleaning solution
With the tiles damp and grit-free, decide whether a homemade paste or a store-bought grout cleaner from Bunnings suits your stains. Bicarbonate of soda paste handles everyday grime and light grey grout well, while oxygen bleach or a commercial gel cleaner works faster on black mould or years of built-up staining. Mix your paste in a small bowl rather than straight on the floor, since a thick, spreadable consistency clings to vertical grout lines and stays put on horizontal ones instead of running off before it can work.
A simple homemade mix looks like this:
3 parts bicarbonate of soda
1 part water
(optional) a splash of white vinegar for extra lifting power
Spoon or spray the paste directly onto the grout lines, avoiding the tile faces where possible, and leave it to sit for ten to fifteen minutes. This dwell time is what actually loosens the dirt, so resist the urge to scrub straight away.
Patience during the soaking stage does more of the actual cleaning work than the scrubbing that follows.
For heavily stained bathroom grout, an oxygen bleach solution diluted in warm water and applied with a spray bottle often outperforms bicarbonate soda alone, particularly when you are removing mould from grout in shower recesses. Check the product label for correct dilution ratios, since oxygen bleach loses effectiveness quickly once mixed and needs to go straight onto the grout rather than sitting in the bottle overnight. Whichever solution you choose, keep the room ventilated and avoid letting it dry out completely on the tiles before you move on to scrubbing, as a crusted paste is harder to work into the grout than one that is still slightly moist.
Step 3. Scrub the grout lines
Once the paste has had its ten to fifteen minutes to work, grab your grout brush and scrub along the length of each line rather than across it, using short, firm strokes. Working in the direction of the grout line stops the bristles from flicking dirty paste onto the surrounding tile faces and keeps the pressure focused exactly where the stain sits. Put some weight behind the brush on stubborn black patches, but check every minute or two to see how much colour is lifting, since over-scrubbing soft or ageing grout can wear it down faster than the dirt ever will.
Scrub along the grout line, not across it, and let the brush do the work rather than your shoulder.
For tight corners, edges around a bathtub, or narrow lines between small mosaic tiles, an old toothbrush or a purpose-built corner grout brush reaches where a full-size brush cannot. Corner and edge grout tends to hold onto grime longest because standard brushes glance off it, so give these spots a second pass once the main floor area is done. If a line is still dark after a solid scrub, reapply a small amount of paste directly to that section and let it sit for another five minutes before going over it again rather than forcing it with brute strength.
Keep a bucket of warm water nearby to rinse the brush regularly, since a bristle head clogged with old paste and grime loses its scrubbing power fast and just smears dirt back into the lines you have already cleaned. Cleaning grout on wall tiles needs the same technique, just work top to bottom so dirty runoff does not drip back over grout you have already scrubbed clean.
Step 4. Rinse, dry and seal the grout
After scrubbing every line, flush the whole area with clean warm water, going over it two or three times to lift every trace of paste, oxygen bleach, and loosened grime. Thorough rinsing matters here because leftover cleaning residue attracts dust and dirt just as fast as the original stain did, undoing your work within a few weeks. Wipe the tiles dry with old towels or a flat mop rather than letting them air dry, since standing water can seep back into porous grout and leave it looking patchy once it dries unevenly.
Give the grout a full 24 to 48 hours to dry out completely before you think about sealing, especially in bathrooms where humidity slows things down. Sealing damp grout traps moisture underneath the sealant, which invites mould rather than blocking it.
Skipping the sealer is the single biggest reason clean grout turns grey again within a few months.
Once the grout is bone dry, seal the grout after cleaning with a penetrating sealer applied by a small applicator brush or foam roller, running it along each line and wiping any excess off the tile face before it cures. Most sealers need a second coat for proper protection, so check the product instructions rather than guessing. A few practical points to keep in mind:
- Test the sealer on a small patch first to confirm it doesn’t discolour light-coloured grout
- Apply in a well-ventilated room and avoid walking on the tiles for several hours
- Reapply sealer every twelve to eighteen months in high-traffic areas like entryways and kitchens
Sealing grout pays off because it resists staining, sheds water, and makes your next clean far quicker than this one.
Keeping your grout looking new
Follow these four steps and most household grout comes up looking close to new, without a professional visit or a specialist toolkit. Sticking to a sensible grout cleaning schedule is what actually keeps it that way: a quick wipe with a damp mop after cooking, and a light scrub every few weeks, stops grime building up into the kind of stain that needs a full paste-and-scrub session again. Sealant does the rest of the heavy lifting, so mark a reminder for twelve to eighteen months out and reapply before the grout starts drinking in every spill.
Some grout, though, has soaked up years of grease, mould, or old stains that no amount of bicarbonate soda will shift, and that’s when scrubbing harder just wastes a weekend. If your tiles need that level of attention, or you’d rather skip the knee work altogether, see what professional grout cleaning costs and involves and get in touch with SMK Carpet Cleaning for a free quote.