Water hardness and limescale

Hardness and limescale


About 80% of the water we supply is from groundwater sources - it is generally hard after dissolving calcium and magnesium salts as it percolated through layers of limestone, chalk or rock. Signs of hard water are poor lathering of soap and limescale. The rest comes from surface water stored in reservoirs which is generally softer.


Signs of limescale include:

  • deposits of scale around taps or basins
  • layers of scale in kettles, which can flake and lead to chalky particles in hot drinks
  • a thin layer of white film on glassware or items from dishwashers
  • flakes in water drawn from taps. This is caused by flaking scale in the pipes and is usually seen in the hot water system
  • floating white film or scum on boiled water (this may pick up colour from tea, etc).

Below are a few tips on how to deal with limescale in your home: