Lime is a natural mineral that can be found as limestone, or, dissolved in water, as calcium carbonate (CaCO3) and magnesium. If the content of calcium and magnesium is high, the water is called hard. In Switzerland, water hardness, or total permanent hardness (GH in Switzerland) - is divided in 6 degrees.
What is lime?
How hard is my water?
Total permanent hardness in °fH / designation
0 to 7 / very soft
7 to 15 / soft
15 to 25 / slightly hard
25 to 32 / moderately hard
32 to 42 / hard
> 42 / very hard
Since 2004, the Ordinance on Foodstuffs has required all water companies to inform about the quality of drinking water supplied at least once a year. Many water companies publish their data at www.wasserqualitaet.ch.
Consumers can search for a certain location and thus obtain the desired water quality data from the data base. Should the desired water company not appear in the data base, we would ask you to call your local authority for further information.
How does lime get in my water?
The greater part of the lime gets into the soil and then into the ground water through seeping rain water, when, depending on the type of subsoil, different minerals dissolve into the water. Among them is calcium carbonate as a component of lime. The lime content may vary greatly depending on the region.
Lime is generally very poorly soluble in water. It can be converted into a readily water-soluble form by reacting with carbonic acid, which is generated when carbon dioxide is dissolved in water. The amount of dissolved lime depends on the content of carbonic acid in the water. This balance is called lime - carbon acid ratio.
A change in this lime - carbon acid equilibrium causes the lime to transform into its water-insoluble form, which deposits on surfaces and can form a layer of limescale.
What are the effects of lime?
Lime and other minerals give the water its natural flavour. The calcium contained in lime also fulfils important functions in the human body, such as in the formation of bones, teeth and cell walls. In addition, a thin layer of lime prevents metal pipes from corroding.
However, if the lime content in the water is very high, this may impair the plumbing and household appliances. When heating the water, carbon acid evaporates as carbon dioxide into the air, which disturbs the lime - carbonic acid equilibrium. Consequently, lime is no longer in its water soluble form.
The precipitated lime deposits on the surfaces of pipes, boilers, household appliances and taps, forming limescale. The consequences can be far-reaching:
- Frequent cleaning and maintenance
- Heat transfer loss in the boiler
- Reduced flow in pipes
- Hygienic problems in the piping system (micro-organisms are protected by the limescale in the plumbing which will facilitate the formation of a biofilm)