What is the permanent hardness of water

Jurassic group


On the sub-pages you can read the quality parameters of our deep wells in Bronn, Scherleithen and Moggendorf as well as the springs in Trockau, Zips and Leups. You can also find the reports and the tests for medicinal and X-ray contrast media as well as pesticides on our download pages.

1. Local network Pegnitz
2. Hollfeld local network
3. Waischenfeld local network
4. Trockau local network

Explanation of the quality parameters of the drinking water
According to the Drinking Water Ordinance (TrinkwV), only water resources are used for the drinking water supply from which permanently unobjectionable water is obtained.
The limit values ​​set by the (TrinkwV) correspond to the maximum permissible value of a substance in drinking water. One criterion for setting the limit value is that compliance with it must not impair human health in the event of lifelong consumption. The limit values ​​also enable a reliable and neutral test of the drinking water!

Degree of hardness
The hardness of the water is understood as the sum of the calcium and magnesium ions it contains. Most of the information is given in degrees of German hardness (° dH). The hardness of the water is in the household z. B. important for the amount of detergent to be used.

On February 1, 2007, the German Bundestag passed the new version of the law on the environmental compatibility of detergents and cleaning agents (Washing and Cleaning Agents Act, WRMG). The law comes into force when it is published in the Federal Law Gazette. According to § 9 of the law, the water supply companies are obliged in the future to indicate the hardness ranges of the drinking water to the consumer as follows:

Hardness range soft (previously hardness range 1)
Less than 1.5 millimoles of calcium carbonate per liter (corresponds to 8.4 ° dH)

Medium hardness (previously hardness range 2)
1.5 to 2.5 millimoles of calcium carbonate per liter (corresponds to 8.4 to 14 ° dH)

Hardness range hard (previously hardness range 3)
More than 2.5 millimoles of calcium carbonate per liter (corresponds to more than 14 ° dH)

These new three hardness ranges replace the old hardness ranges. The information must be given in millimoles of calcium carbonate per liter (which is internationally common for hardness information). It is assumed that the total hardness (sum of the concentrations of calcium and magnesium, calculated as calcium carbonate) has to be stated. However, the law makes no statement on this.

The new hardship areas are based on European law; The EU detergent regulation obliges detergent manufacturers to provide dosage recommendations for these three hardness ranges.

A limit value is not defined in the Drinking Water Ordinance.

PH value
The pH value is the measure of the hydrogen ion content of the water. In drinking water, the aim is to achieve a pH value that corresponds to the lime-carbonic acid balance, i.e. the water is then neither lime-aggressive nor lime-separating. According to the Drinking Water Ordinance, the pH value should be between 6.5 and 9.5.

Acid capacity / base capacity
These values ​​indicate the amount of an acid or base that has to be added to the water in order to achieve a certain pH value. They are an expression of the water's buffering capacity. The buffering capacity is decisive for the corrosion-chemical behavior of the water in the pipe network and should be as high as possible. There are no limit values ​​for these parameters.

Sulphate (SO4)
Sulphate ions are made up of oxygen and sulfur. Sulphate is contained in serum in the human organism and is produced by the body itself from sulfur compounds.

According to the Drinking Water Ordinance, the limit value for sulfate is 240mg / l.

Nitrate (NO3) / nitrite (NO2)
The TrinkwV 2001 contains a common limit value for nitrate and nitrite, which must not be exceeded for a value to be formed from both concentrations.

The limit value for nitrate / nitrite according to the Drinking Water Ordinance TrinkwV is 50 mg / L.