Limescale in water: a nuisance or healthy?

When most people think of limescale, they think of unsightly deposits on the tap, ugly stains on the laundry or a broken washing machine - in short: annoyance. However, limescale is not a pollutant, but a chemical compound that is naturally present in Tapwater 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 examples of what happens when calcareous soils react with acid rain. The chemical substance consisting of calcium, carbon and oxygen with the formula CaC03 is less desirable in the household. 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 our health.

Limescale does not cause problems everywhere, as the limescale content is only high in some places and very low in others. The limescale content determines the hardness of the water. In some regions, the water is "hard" and the limescale content in the water can also cause technical problems, especially there. For example, when water evaporates, the limescale leaves behind deposits. Particularly in places where limescale builds up over a long period of time and cannot be easily removed, there is a risk of damage. Washing machines, steam irons and coffee machines become calcified and energy consumption increases.

The calcium and magnesium contained in lime is even important for the body's mineral balance. Calcium is necessary for building bones and teeth. Magnesium, on the other hand, is an important substance for protecting muscles and bones. Excess minerals are excreted naturally. However, there are always misunderstandings here: Calcium in water definitely has nothing to do with calcification in the body. Arteriosclerosis (hardening of the arteries) is caused by fats, high blood pressure and other stressful factors and not by calcareous water.¹ From a medical point of view, there is no reason to filter limescale out of drinking water.

Water with a high limescale content affects the taste. This can be particularly noticeable when drinking hot drinks such as coffee or tea. Passionate tea connoisseurs often refuse to prepare their favorite 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-top jug filters are often used. However, these also have disadvantages and must be in perfect condition to prevent germs from accumulating.

The water hardness can be easily determined using test strips, or more conveniently via the website www.wasserhaerte.de

Anyone who wants to reduce limescale in the 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 metal 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, high installation costs and the need for regular maintenance. Another way to reduce the limescale content in the water is to add certain substances. However, these in turn lead to contamination or changes in the water. Methods of biological or physical limescale treatment, sometimes also called "alternative" limescale removal, are more environmentally friendly. This involves the use of electric and magnetic fields or technical devices such as water turbulence. When removing limescale from the water, it should also be noted that the water becomes more aggressive and can therefore clog pipes. Alternatively, a water filter can be used at selected connections.

Warm or hot water promotes limescale deposits in household appliances

As water hardness varies greatly from region to region, measurement parameters were developed early on. The lime content of the water is continuously monitored by the local waterworks. Based on the water hardness at your place of residence, which is easy to determine, you can decide for yourself whether you want to reduce the limescale content or not.
The limescale content is divided into three levels: "soft", "medium" and "hard" with the unit "dh", i.e. "degree of German hardness". However, the Detergents and Cleaning Agents Act uses the new unit of millimoles per liter, which can also be used for 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 soft water in coastal regions in northern Germany and hard water in southern Germany. However, this cannot be generalized.

Very high degrees of hardness are found in southern Germany in particular.

"Hard, but healthy" - this is a simple formula for limescale in water. A certain calcium and magnesium content in Tapwater is supportive due to its anabolic effect. There is no risk of physical calcification due to the use of calcareous water. However, limescale in water can have problematic consequences for technical appliances, pipes and installations. Certain water filtration processes can effectively reduce the limescale content in water.