The pH value indicates whether water is neutral (pH 7), acidic (under 7) or alkaline (over 7). A large amount of minerals indicates water hardness. Mineral water is therefore exceptionally hard water.
Details of water hardness
Water hardness is set e.g. on a German scale of hardness (d° or dH°):
| 1. | 0 – 7 °dH | soft |
| 2. | 7 – 14 °dH | medium-hard |
| 3. | 14 – 21 °dH | hard |
| 4. | nad 21 °dH | extra-hard |
Water with the medium degree of hardness is considered to be the most suitable drinking water. Drinking water should have the pH between 6, 5 to 9.
Source: SIEA- www.zitenergiou.sk, www.spp.sk, www.protherm.sk, www.zmakčovace-vody.sk