If you're staring at grimy grout lines and a recipe that calls for borax, here's the short version: borax is hard to find for cleaning use in the UK in 2026, and washing soda plus a stiff brush does the same job for most households.
- Washing soda (sodium carbonate) is the closest borax substitute for cleaning grout in 2026 — cheap, alkaline, and easy to find.
- Regn's Toilet Cleaning Tablets tackle limescale-heavy bathroom grout without bleach — Buy for hard water areas.
- Pair any paste with a stiff coconut scourer, not a flat sponge, or you'll just move the grime around.
- Skip bleach-based grout pens on coloured grout — they lighten unevenly and don't touch mineral buildup.
Why this matters
Borax used to be the go-to grout paste ingredient because it's alkaline enough to cut through soap scum and mild enough not to strip grout sealant. Most UK shops stopped stocking it for cleaning use years ago, and the old recipes floating around blogs still assume you can buy a box at the supermarket.
That's the gap. You need something with similar alkalinity, similar safety profile, and similar price — not a specialist product that costs more than the problem is worth. Regn's guide on using a borax substitute for natural cleaning covers the chemistry in more depth; this page is about matching the substitute to grout specifically, because grout behaves differently to laundry stains or oven grease.
Who this is for
This is for anyone with tiled kitchens, bathrooms, or hallways where the grout has gone from white to grey and the usual spray-and-wipe isn't cutting it. It's especially relevant if you've got hard water, kids or pets tracking dirt across tile, or you're simply trying to cut plastic bottles and harsh chemicals out of the cleaning cupboard without losing cleaning power.
What to look for in a borax substitute for cleaning grout
Alkalinity that actually lifts grime
Grout grime is a mix of soap scum, mineral deposits, and trapped dirt — all of which respond to an alkaline solution, not an acid. Washing soda sits at a pH of around 11, close enough to borax's 9.5–11 range to do the same job. Anything milder than a pH of 9 will need much more scrubbing time to shift the same stain.
Safe for daily-use rooms
Kitchens and bathrooms are the two rooms you're in every single day, so whatever you're mixing needs to rinse clean and not leave residue kids or pets can pick up. This rules out anything requiring gloves and ventilation warnings for a job you'll repeat every few weeks.
Won't strip or discolour grout sealant
Sealed grout has a thin protective layer, and anything too abrasive or too acidic breaks that seal down over a handful of uses. A paste that's alkaline but not caustic — washing soda, bicarbonate, or a mineral-based powder — cleans without eating through the sealant the way neat bleach does.
Works with a brush, not just a spray
Grout lines are recessed, so a spray-and-wipe approach leaves paste sitting on the surface tile while the actual grout line stays untouched. You need something with a stiff enough brush to physically agitate the mixture down into the line — this matters more than the cleaning agent itself for genuinely dirty grout. Regn's piece on cleaning brushes for grout and tile lines goes into brush shapes if you want the full comparison.
Actually available to buy
The whole point of finding a substitute is that borax itself isn't sitting on a shelf near you in 2026. Washing soda, bicarbonate of soda, and mineral-based cleaning powders are all stocked in supermarkets or available online, which is more than you can say for the thing you're replacing.
Cost per clean
Grout cleaning is a repeat job, not a one-off, so a £15 specialist product that lasts two cleans isn't a substitute — it's a downgrade. Anything you pick should cost pennies per application if you're making a paste, or a few pounds per use if you're buying a ready-made tablet or powder.
Top picks
Washing soda paste — the default swap Mix three tablespoons of washing soda with a small amount of warm water until it forms a thick paste, then work it into the grout with a brush and leave for 10 minutes before rinsing. A 500g box costs under £2 and lasts through dozens of cleans. Buy — this is the closest like-for-like replacement for borax on grout, full stop.
Regn Toilet Cleaning Tablets, 10-pack — the hard water pick If your grout problem is really a limescale problem — chalky white buildup rather than grey grime — a mineral-based tablet designed for limescale removal does more than an alkaline paste ever will. Regn's Toilet Cleaning Tablets are formulated for deep-clean limescale removal and work on bathroom floor grout the same way they work on the bowl. Buy for hard water areas, Skip if your water's already soft.
Coconut kitchen scourers — the scrubbing partner A paste is only half the job; you need something abrasive enough to work it into the line without scratching the sealant. Regn's Coconut Kitchen Scourers are made from 100% coconut fibre, tough enough for kitchen grout, soft enough not to score the tile edges. Buy — pair with the washing soda paste above.
7-piece kitchen cleaning brush set — the detail pick Flat scourers can't reach into a narrow grout line the way a dedicated grout brush can. A multi-head brush set covers everything from wide floor grout to the tight corners around a sink splashback, and having the right head size cuts scrubbing time roughly in half compared to a single flat sponge. Consider — worth it if you're doing a full room rather than a quick touch-up.
Vinegar and bicarbonate paste — the light-maintenance option For grout that's only mildly dull rather than genuinely stained, a simple bicarbonate-and-vinegar paste applied weekly keeps things from building up in the first place. It fizzes on contact, which loosens surface dirt but won't shift set-in mineral deposits the way washing soda or a limescale tablet will. Consider for upkeep, Skip if you're already dealing with grey, ingrained grout.
What to avoid
- Neat bleach on coloured grout — it lightens patchily, leaving uneven pale patches that look worse than the original grime, and it does nothing for limescale.
- Old recipes that still list borax as an ingredient — most weren't updated once it disappeared from general retail, so you'll be shopping for something you can't easily buy.
- Fine microfibre cloths for scrubbing — they're built for wiping, not agitating paste into a recessed line, so you'll spend twice as long for a worse result.
If the paste doesn't fizz or foam slightly when it hits the grout, you haven't got enough alkalinity in the mix to lift mineral deposits.
Verdict comparison
| Option | Best for | Cost per use | Verdict |
|---|---|---|---|
| Washing soda paste | General grey grime, all rooms | Pennies | Buy |
| Regn Toilet Cleaning Tablets | Hard water, limescale-heavy grout | Under £2 | Buy for hard water |
| Coconut Kitchen Scourers | Scrubbing partner for any paste | Under £1 | Buy |
| 7-piece brush set | Detail work, full-room jobs | One-off cost | Consider |
| Vinegar and bicarbonate paste | Light, weekly maintenance | Pennies | Consider |
FAQ
What is the best borax substitute for cleaning grout in 2026?
Washing soda (sodium carbonate) is the closest borax substitute for cleaning grout, matching its alkalinity at a similar cost. Mix it into a paste with warm water and scrub with a stiff brush for grey, grimy grout lines.
Can I still buy borax in the UK for cleaning?
Borax is difficult to find for general retail cleaning use in the UK, which is why substitutes like washing soda and bicarbonate of soda have become the standard swap. Most supermarket and online cleaning ranges no longer stock it under that name.
Is washing soda safe to use on grout?
Washing soda is safe on sealed grout when rinsed thoroughly after use, though it shouldn't be left to sit for more than 10-15 minutes at a time. It's an alkaline mineral, not a caustic chemical, so it doesn't carry the same handling warnings as bleach.
How often should you clean grout with a borax substitute?
Once every 2-4 weeks for high-traffic kitchens and bathrooms keeps grout from building up mineral deposits or soap scum. Lighter maintenance with a vinegar and bicarbonate paste weekly can stretch that interval further.
Does vinegar work as well as borax on grout?
Vinegar handles light surface dirt but doesn't match washing soda or borax on set-in mineral deposits and grey grime. It's better suited to weekly upkeep than a deep clean.
What should I avoid using on coloured grout?
Avoid neat bleach on coloured grout, since it lightens unevenly and leaves patchy pale marks rather than a uniform clean. A mineral-based paste or limescale tablet cleans without stripping colour.
Do I need a special brush for grout cleaning?
A stiff-bristled brush that fits into the recessed grout line does more for results than the cleaning agent itself. Flat sponges and microfibre cloths sit on the tile surface rather than working paste into the line.
Is a mineral-based cleaning powder better than washing soda for grout?
Mineral-based powders formulated for limescale outperform washing soda specifically in hard water areas where chalky white buildup is the main problem. For general grey grime without limescale, washing soda does the job for less.
One last thing
The grout itself rarely needs replacing — what looks like permanent staining in 2026 is almost always mineral buildup sitting on top of the sealant, which is exactly what an alkaline paste is built to shift. Test a small patch first if you're not sure whether your grout is sealed or bare; unsealed grout absorbs paste faster and needs a shorter contact time to avoid over-saturating the line.
