How do I make my water alkaline

Chemical-physical terms related to water

Water hardness

The hardness of the water depends on the content of calcium and magnesium ions (lime builders) in the water. The higher the "lime content", the harder the water. The total hardness in Central Europe is given in "degrees of German hardness" (dH). One degree of German hardness (1 ° dH) corresponds to an amount of 10 mg calcium oxide (CaO) equivalents or an amount of 7.15 mg dissolved calcium ions.

The harder the water, the more soap or detergent is required. The reason for this: lime binds the soap during washing. If water is heated, the lime precipitates (scale formation from approx. 60 degrees Celsius). This leads to the calcification of pipes, boilers, washing machines and other devices. Hard water should therefore only be heated to a maximum of 60 ° C.

The hardness of the water also has an influence on the preparation of food.

It contributes significantly to good taste and has a beneficial effect on bones, teeth, heart and circulation, because the hard, hard drinking water provides the organism with the important trace element calcium and thus helps to meet the daily calcium requirement. However, high lime content increases the cooking times of meat and vegetables.

PH value

"pH" is the abbreviation for "potentia hydrogenii" and stands for the concentration of hydrogen in an aqueous solution. In mathematical terms, pH is the negative decadic logarithm of the hydrogen ion concentration. It states whether a solution is acidic, neutral or alkaline (basic).

The pH value of pure water is usually in the neutral to weakly alkaline range (pH 7.0 to 7.5).

  • pH value below 7: solution is acidic
  • pH value equals 7: solution is neutral
  • pH value above 7: solution is alkaline or basic

The pH value of water mainly depends on the molar ratio of free carbonic acid to hydrogen carbonate. Carbon dioxide in particular increases the number of hydrogen ions and thus lowers the pH value (if the water is acidic, the hydrogen ion content is increased and the pH value is below 7).

Pure water has a pH value of 7 at 22 ° C. Treated water can have a pH value above 8. Acidic water with a pH value below 7, even if the degree of hardness is low, can have disruptive, material-attacking properties technically or when used in the household (corrosion).


If water is contaminated with dangerous ingredients, these can usually not be seen with the naked eye. Visible cloudiness is not necessarily dangerous.

A milky cloudiness of the water, which disappears in the glass after a short standstill, can easily arise from oversaturation with air. Like the cloudiness caused by sand or clay, this is hygienically completely problem-free.

If water contains iron, the taste changes. Organic substances and waste materials can also cause cloudiness, but these are no longer problem-free.

Sudden clouding of the groundwater and spring water indicates that insufficiently filtered rainwater is penetrating the groundwater and spring water reserves. The cause of discoloration or cloudiness can also be defective pipelines, which lead to contamination of the water.

Electric conductivity

The electrical conductivity indicates the sum of all dissolved, dissociated substances (ions, electrolytes) in the water. The more dissolved substances there are in the water, the higher its electrical conductivity. The unit of measurement for this is micro - Siemens per cm (µS / cm).

Distilled water, for example, has a very low value - it conducts electricity very poorly. Hard water, which, in addition to calcium and magnesium, also contains high concentrations of nitrate, chloride and sulfate ions, has a high conductivity value.

If the conductivity of the water is high, but not due to geological factors, it can be concluded that the water is contaminated with inorganic substances.