Water hardness and limescale

Hard water and limescale

Most of the water we supply is from groundwater sources - it is naturally hard after dissolving calcium and magnesium salts after percolating through layers of limestone, chalk or rock. Here are a few tips on what you can do.

While there is evidence to suggest that hard water can be good for your health, it can cause limescale in household appliances.

How to deal with limescale


Plastic kettles tend to be worse than metallic ones because they are smoother and hold the scale less firmly. 

Try brushing the sides of the kettle with a stiff nylon brush to dislodge the scale or fill it with a solution of vinegar and water and leave it for four hours. The kettle should be rinsed, boiled and rinsed again before re-use.  

Descaling solutions are also available from most hardware shops and chemists.


A built-in softener in dishwashers uses salt to reduce water hardness. This stops a white film forming on glassware or crockery and will prolong the life of the appliance itself. Don’t forget to refill the dishwasher containers with salt and rinse aid when they need it. 

Some dishwashers need setting to a water hardness level to get the best performance – check your appliance manual for instructions and remember to use the correct value which will be given as a degree of hardness (Clark/UK, French or German).

Use our postcode checker to get information on the hardness of our water supply. 

Showerheads and taps

Limescale can build up in and around taps and shower heads. To clean use descaler or vinegar or citric acid (lemon juice) solution. Rinse fully afterwards.

Water softeners

We do not soften water artificially during the treatment process and do not recommend softened water for drinking and cooking purposes. 

If you prefer your water to be soft, you can install a domestic water softener in your home. 

If you do so, it is recommended that you have a separate tap installed to supply unsoftened water straight from the mains for drinking and food preparation.

Water conditioners

These alter the nature of the hardness minerals which form hard scale when the water is heated. Unlike softeners, they do this without changing the chemical content of the water.

There have been reports that in some cases conditioners do not work or are not as effective as expected. We don't recommend using water conditioners.