Last Updated on October 26, 2026 by Royal Stone Care
Thames Water says that more than 60% of us in the UK live in areas where the water is hard. And that includes London and Kent (among other areas), due to their limestone and chalk geology. Essentially, hard water means high levels of magnesium and calcium compounds, which cause limescale.
Granite is comparatively impervious, and minimally absorbent. But liquid can still soak into its pores if the stone is unsealed.
So while it may sound unlikely, hard water can cause staining, And this can seriously dull the overall appearance of your natural stone. When the minerals in it combine with soap, you get a chemical reaction which leaves a soapy, filmy scum in its wake. With time, these deposits from standing water can form a scaly build-up which can spoil your beautiful worktops’ appearance.
Of course, not all watermarks are caused by hard water. Simpler stains can happen when a drinking glass has been on, say, a worktop for too long. When this happens, small drops of condensation from the glass can mark your granite.
And this can be dispiriting if this discolouring remains, especially if you have spent a lot time on granite cleaning.
However, there are a number of simple things you can do to deal with this problem. Here are some of them:
How to prevent watermarks in the first place
- Frequent cleaning: Mop up any spillages, especially water droplets, immediately. If they dry in place, they could stain the surface of the stone. So be quick!
- Adequate sealing: Seal your granite and then reseal it regularly, typically every year or so. Over time, sealants can lose their effectiveness.
- Avoid prolonged contact with liquid: Don’t leave water (or indeed any liquid) on the stone for any length of time – wipe up promptly.
Clean your stone regularly
This really is the best thing you can do to prevent water marks. Clean your surface with a soapy sponge, but make sure you rinse thoroughly afterwards to remove any lingering soap scum traces. Equally, be sure to dry the surface with a microfibre cloth. This will mop up all the water. And it also means you won’t scratch the sealant.
For regular cleaning, you can use washing-up liquid and water or a natural stone cleanser. Also use a brush with soft bristles, or a sponge. (A natural-stone cleaning product also helps preserve the sealant and so reduces the chances of damage to your granite.)
As well as cleaning, remember also to seal your granite regularly.
Tackle immediately
Even small volumes of standing water can leave behind hard-to-remove mineral deposits which build up. So wipe up water from granite countertops straight away.
Dealing with water stains
For lighter staining, such as that from condensation drops, try cleaning using a combination of mild washing-up liquid, warn water and a little rubbing alcohol. If the mark appears to be a little more stubborn, you may need to apply a specialist granite cleaning product. Alternatively, make up a poultice of baking soda and hydrogen peroxide and place over the mark where it can draw out the moisture. Leave under a plastic wrap for at least 24 hours before removing with a damp, soft cloth. (Clearly, you don’t want to use any abrasive tools which could scratch your surface.)
Try a poultice or paste
If you have a scaly build-up of hard water, reach for something stronger. Clearly, you’ll want to give abrasive products a swerve. But you could consider using a paste of water and baking soda. Just apply it to the area affected and rub with soft-bristled brush before rinsing and drying off with a microfibre cloth.
For a poultice, make the same paste of water and baking soda, apply and cover with a plastic wrap and leave for 24 hours. Reapply if you need to.
The last resort: a razor blade
It really is the last resort, this option. But if you’re feeling brave, use a single-edged razor to scrape away carefully at the mineral build-ups on the granite surface. This idea certainly wouldn’t be for everyone, but you can get rid of scaly deposits without damaging your stone. So it could just do the trick.
Is there anything I shouldn’t use?
Don’t use neat rubbing alcohol or hydrogen peroxide. This can ultimately do more harm than good to your granite. Equally, as ever, steer clear of lemon juice, bleach, ammonia and vinegar. At the same time, don’t use abrasive cleaning implements like steel wool or Brillo pads.
Steer clear of vinegar
While this mat seem like an obvious choice for granite cleaning, vinegar contains acids. These can erode the sealant protecting the surfaces of your natural stone.
Talk to us
If you’re in the London area, we specialise in granite cleaning, granite chip repair in London and everything else related to the care of this beautiful natural stone. Contact us to learn more, and for an informal, free and no-obligation quote, whether you’re a private or business customer.
