The most important information and tips on the hardness of water
People in Germany receive drinking water from the water suppliers in their respective home regions. The water is extracted from groundwater in wells or from surface waters such as rivers, lakes or reservoirs. But the forest also serves as a waterworks. The water is then purified according to very strict quality specifications. The drinking water obtained in this way is continuously extracted and analysed at various points in the process and distribution system. The health authorities are also involved in this, as they monitor the proper tests at the water suppliers by approved laboratories. All this ultimately leads to the fact that the drinking water is of very high quality and can be used safely as a daily thirst quencher. You can find out more about this in our guide "Interesting facts about drinking water". Good to know: The hardness of water has nothing to do with its quality.
What does the hardness of water mean?
Depending on the soil conditions, the so-called water hardness can vary greatly in a region. The terms "hard water" and "soft water" refer to the amount of minerals such as magnesium and calcium in the water that are dissolved from the soil. How high their concentration is depends on the different rock layers through which the water flows. In regions with a lot of sandstone and limestone, the hardness of water is high, in regions where the subsoil consists of granite or basalt, for example, it is rather low.
How many degrees of hardness are there in water?
In Germany, we have been classifying water hardness in three levels since 2007. Level one means a rather soft water with a low proportion of calcium and magnesium. These minerals are mainly responsible for the formation of lime (calcium carbonate) and determine the hardness of the water. In other words, the hardness of water is equivalent to its lime content. That's why level two water has a medium lime content, and level three water is called hard water with a high lime content.
The local waterworks are obliged to publish the current water hardness at least once a year. It is given in °dH (degree of German hardness). The officially defined classification of the water hardness can be found in the following table:
|
Hardness range |
Calcium carbonate per liter in millimoles |
Hardness (°dH) |
|
soft water |
Less than 1.5 mmol/l |
under 8.4 |
|
medium-hard water |
1.5 to 2.5 mmol/l |
8.4 to 14 |
|
hard water |
over 2.5 mmol/l |
over 14 |
What is the ideal water hardness?
The good news is that a high lime content, which causes unsightly calcifications on tiles or fittings as well as inside household appliances, for example, is still completely harmless to health. In fact, the human body needs various minerals. If it absorbs these through drinking water, among other things, this can have a positive effect on the supply of the organism. However, many people find soft water more pleasant, for example when showering, or they prefer the taste. Soft water is also best for household appliances, as there are only minor limescale deposits.
Good to know: All drinking water suppliers in Germany offer corresponding legally required overviews on their websites on the Internet, in which substances and their quantities in the respective water are listed. The total hardness in enercity's supply area is in the "medium" range. An exception is made in sub-areas in Seelze and Laatzen, where the degree of hardness "soft" is indicated. More on this on our Water quality overview page.
Three methods to measure water hardness
There are a few different ways to find out what hardness your water is. The easiest way is to inquire directly online with the water supply company. If you want to measure yourself, there are the following alternatives:
- Dipstick: You can buy water hardness test strips at the pharmacy or on the Internet. If you put the test strip in a glass of water, it changes color and indicates how hard the water is.
- Titration solution: A test with titration solution is also fast and effective. You can buy the chemical liquid online. To test, simply drip the amount described in the instructions into a glass of water with a pipette and determine the degree of hardness based on the discoloration.
- TDS Device: Total Dissolved Solids devices are used to measure the water quality of aquariums. They use the electrical conductivity of the water to measure how many solids such as minerals, salts and metals are contained. The degree of hardness of the water can be derived from the measured value.
Can the hardness of water be influenced?
If you live in a region with very hard water and prefer softer water, there are different ways to soften the water. The easiest way to do this is with a water filter or a water softening system. The latter is a more costly investment, but it provides softer water throughout the home when integrated directly into the pipe. Alternatively, a filter system can be attached to the sink, for example, and decalcifies the water before it comes out of the tap.
A special filter jug can be used to descale smaller amounts of water, for example for making coffee or tea. But boiling water also decalcifies this. You can observe the process on the lime edge that forms in the pot. However, this method consumes a comparatively large amount of energy and is not only a burden on your wallet, but also on the environment.
What role does the hardness of water play in detergent dosage?
In the past, special descalers had to be added to the machine in addition to the detergent to soften the water and thus protect the appliance and reduce limescale deposits in the laundry. Since modern detergents already contain limescale removers, descaling the washing machine is no longer necessary nowadays - provided that the agents are dosed according to the recommendation on the packaging. To do this, it makes sense to know what water hardness prevails in your region.
How can unsightly limescale stains be removed from surfaces?
The harder the drinking water, the faster ugly limescale stains appear – for example in the sink, on the tiles and fittings. If you don't always wipe away the water, you will soon have stubborn, dull limescale stains on surfaces. But that's not so bad: With diluted vinegar or lemon essence, the stains can be easily removed again. Tip: In the case of particularly stubborn calcifications, the affected areas should be soaked with the cleaning agent for several hours so that the limescale dissolves.
How are electrical appliances freed from calcification?
Electrical appliances should also be descaled regularly, otherwise the performance of the appliance will suffer in the long run - in the worst case, it will even break. Fortunately, there are simple and inexpensive solutions that are harmless to health. Just like on surfaces, calcification in electrical appliances such as coffee machines, water or egg cookers can also be removed with citric acid or vinegar.
Don't forget: then rinse several times with clear drinking water so that the taste of the coffee machine or kettle does not occur. In drugstores and supermarkets you can also buy ready-made lemon or vinegar descaling agents.
And what about calcified water pipes in the building?
In rare cases, water pipes in the house can calcify and the water pressure suffers, for example if the strength of the water jet decreases. In such a case, it is advisable to consult experts, for example a plumber for drinking water. This person can provide information on how pipes can be flushed and cleaned – or whether a new installation will even be necessary. By the way, the main inlet for drinking water should always be completely open so that there is sufficient pressure on the house installation and the pipes are well flushed. Otherwise, unwanted germs can form. This is already the case after four hours of water standstill in the pipes! Therefore, the drinking water should always be left running until the water is nice and cold. Then it is fresh and edible.
source : Was bedeutet der Härtegrad von Wasser? (enercity.de)