Lime in water: annoyance or also healthy?
What is lime?
When people think of limescale, they think of unsightly deposits on the tap, ugly stains on the laundry or a broken washing machine - in short: annoyances. However, lime is not a harmful substance, but a chemical compound that is naturally present in tap water in varying concentrations. In nature, the calcium carbonate dissolved in water is present in calcareous rock layers and is absorbed by rainwater. Stalactite caves with their stalagmites are wonderful witnesses of what happens when calcareous soils react with acid rain. In the household the chemical substance of calcium, carbon and oxygen with the formula CaC03 is less desirable. The poorly soluble salt must be removed with cleaning agents with a low pH value, for example table vinegar or citric acid. But despite all the problems, lime is better than its reputation and is even necessary for health reasons.
What problems does lime cause?
Lime does not cause problems everywhere, because only in some places the lime content is high, in others also very low. The lime content determines the hardness of the water. In some regions the water is "hard", and especially there technical problems can be caused by the lime content in the water. For example, when water evaporates, the lime leaves deposits. Particularly in places where lime deposits are formed over a long period of time and cannot be easily removed, there is a risk of damage. Washing machines, steam irons and coffee machines calcify and energy consumption increases.
In the worst case, the devices become unusable. In pipelines, calcification reduces the flow rate and eventually leads to clogging. This can be unpleasant and expensive, especially in kitchens. Fittings break down when the mixer tap lets only a little water through. Or an aerator can no longer be unscrewed because it has seized up. However, many of the problems caused by lime can be solved with household remedies.
But what about health risks? In fact, calcification in pipes or on jet regulators can pose a health risk because bacteria can attach themselves more easily. This is especially true for pipes that are rarely used and where water stagnates (the water stands for several hours). However, the lime content is not a health problem in itself; on the contrary, it is actually beneficial.
No health damage due to lime in the water
The calcium and magnesium contained in lime is even important for the mineral balance of the body. Calcium is necessary for building bones and teeth. Magnesium in turn is an important substance for protecting muscles and bones. Excess minerals are excreted naturally. Again and again, however, misunderstandings arise here: Lime in water definitely has nothing to do with calcification in the body. The so-called arteriosclerosis (hardening of the arteries) is caused by fats, high blood pressure and other stress factors and not by water containing lime.1 From a medical point of view, there is no reason to filter out lime from drinking water.
Impairment of taste by hard water
Water with a high lime content influences the taste. This can be particularly noticeable when enjoying hot drinks such as coffee or tea. Passionate tea connoisseurs often refuse to prepare their favourite drink where the water has a high degree of hardness. The aroma of tea and coffee can develop better in soft water. This is one reason why table pot filters are often used. However, these also have disadvantages and must be in perfect condition to prevent germs from accumulating.
Reduce lime in tap water
Anyone who wants to reduce limescale in water usually does so to protect the domestic drinking water installation and connected appliances. A domestic water filter is required for this. Such filters are even mandatory for metallic pipes. However, very special filters are required to remove limescale: one of the most common methods of water softening is the use of ion exchange filters. The disadvantages of this method are the increased sodium content in the water, a high installation effort and the regularly necessary maintenance. Another way to reduce the lime content in the water is to add certain substances. However, these in turn lead to a contamination or change in the water. More environmentally friendly are methods of biological or physical lime treatment, sometimes called "alternative" lime removal. This involves the use of electric and magnetic fields or technical devices such as turbulence of the water. When removing lime from the water, it should also be noted that the water becomes more aggressive and can clog pipes. Alternatively, a water filter can be used at selected connections.
Water hardness as decision criterion
Since water hardness varies greatly from region to region, measured variables were developed at an early stage. The lime content of the water is continuously monitored by the local waterworks. Based on the water hardness at the place of residence, which is easy to determine, you can decide for yourself whether you want to reduce the lime content or not.
The lime content is divided into the three levels "soft", "medium" and "hard" with the unit "dh", i.e. "degree of German hardness". However, the Detergents and Detergents Act uses the new unit millimol per litre, which is also applicable to other salts and substances in water. One mmol/l corresponds to 5.6 °dh.
The three hardness ranges are divided into:
-less than 8.4 °dh = soft water
-8.4 to 14 °dh = medium-hard water
-more than 14 °dh = hard water2
In general, there is a tendency towards rather soft water in coastal regions in northern Germany and hard water in southern Germany. However, this cannot be generalised.
Exemplary water hardness at selected German locations:
|Berlin (14 °dH)||Stuttgart (13 °dH)||Hamburg (7 °dH)|
|Munich (16.3 °dH)||Leipzig (13.5 °dH)||Bremen (7 °dH)|
|Cologne (18 °dH)||Nuremberg (14 °dH)||Flensburg (8 °dH)|
If you look more closely, you will often find different information on water hardness at the same place of residence. In fact, the water hardness can also vary considerably over a small area. Good examples are Hamburg and Leipzig. The different values depend on the source from which the drinking water is obtained. If you want to know exactly, in order to take measures if necessary, you can search for the right water hardness with a postcode search at Wasserhaerte.net3 inform.
"Hard, but healthy" - this is how you could put the topic of lime in water in a simple formula. A certain calcium and magnesium content in tap water is supportive due to its anabolic effect. There is no risk for physical calcification symptoms due to the use of water containing lime. However, lime in water can have problematic consequences for technical equipment, pipelines and installations. Certain water filtration processes can effectively reduce the lime content in water.
- Water test online https://www.wassertest-online.de/blog/kalkhaltiges-wasser-trinken/
- Berliner Wasserbetriebe www.bwb.de
- Water hardness https://www.wasserhaerte.net/