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Water Hardness

The hardness of water depends on the amount of calcium per litre – the more it contains, the harder the water is. See the map below for hardness levels in the UK:

Hard Water Map

When rain falls, it doesn't contain calcium. But as it flows over the land and filters through rocks, it dissolves minerals and becomes harder.

The amount it picks up depends upon the geology of the area, and the hardness of water varies widely throughout the country.

The majority of water supplied in the UK is hard; it comes from underground chalk aquifers where the levels of calcium are very high, but the hardness varies from source to source.

Hard water can lead to the formation of lime scale in water systems and household appliances, but this can be avoided by using water filters.

How water hardness is defined:

  • Soft water contains less than 30mg of calcium per litre
  • Moderately hard water contains between 30 and 60mg
  • Hard water between 60 and 120mg
  • Very hard water contains more than 120mg of Calcium per litre

When hard water is heated, harmless lime scale is formed.

Regular cleaning of kettles will prevent the 'scum' floating to the surface, while keeping the temperature of the hot water systems below 60°C will reduce the formation of lime scale in boilers, on heating elements and in hot water pipes.  However the most effective way of protecting your kettle and taps is to use a water filter.

A white film or spots on shower doors, glassware or fixtures may also indicate hardness. The film may also be left on skin and hair after bathing, resulting in dryness and the use of extra hair products and lotions. Additionally, hard water can leave mineral deposits in pipes and water using appliances. This is apparent when the flow of water is decreased or when appliances become inefficient or need multiple repairs. According to the Water Quality Association, a consumer's water heating costs could increase as a result of hard water. When hard water is heated, the minerals can precipitate and form scale. This scale build-up forms an insulating barrier between the heating element and the water to be heated.

Hardness also has an effect on soaps and detergents. The cleaning properties of detergents and the amount of suds produced are diminished. Calcium and magnesium ions actually react with soaps and detergents to create “soap curd”, sometimes called “soap scum”. Soap curd reduces the life of clothing and makes them look grey or faded!

At Finerfilters Ltd we have over 25 Years of experience in water filtration to help you, whether it be a simple under sink filter system to protect your kettle and taps. Whether it is for an on demand boiling water system, or even commercial coffee and vending machines, we have the answer.

Check out our website for a full range of water filters, or contact our friendly knowledgeable sales team, who will happily give you the best advice for you needs.