Ground water protection and drinking water quality - two sides of the same coin
The task of sustainable, future-oriented ground water protection is to constantly or temporarily reduce or entirely prevent the entry of contaminants into the ground water, be that on a small or large scale, as much as possible. In addition, water protection areas have been designated and possible dangers to the ground water are under constant monitoring.
Due to its complex and regular monitoring water is one of most stringently inspected products available. The supply of people with drinking water is subject to the very strict specifications of the German Drinking Water Ordinance. In the framework of drinking water analyses, more than 100 individual parameters are inspected. At the Landeswasserversorgung, this amounts to well above 200,000 separate analyses per year.
| Parameter | Dimension | Limit value according to the German Drinking Water Ordinance |
SA 1 | SA 2 | SA 3 |
|---|---|---|---|---|---|
| pH value | – | ≥ 6.5 and ≤ 9.5 | 7.51 at 11.6 °C |
7.40 at 10.6 °C |
7.97 at 9 °C |
| Calcium | mg/l | – | 73 | 78 | 48 |
| Chloride | mg/l | 250 | 27.3–34.7 | 18.2 | 6.5 |
| Iron | mg/l | 0.2 | <0.01 | <0.01 | 0.0028 |
| Magnesium | mg/l | – | 11,4 | 8.5 | 7.9 |
| Sodium | mg/l | 200 | 12.2 | 5.6 | 5.1 |
| Sulphate | mg/l | 240 | 22.3–31.2 | 13.3 | 35 |
| Lead | mg/l | 0.025 | <0,001 | <0,001 | <0,0005 |
| Fluoride | mg/l | 1.5 | 0.06 | 0.05 | 0.09 |
| Nitrate | mg/l | 50 | 21.2–25.0* | 30.7 | 4.5 |
| Polycyclical aromatic hydrocarbons | mg/l | 0.0001 | <0,0001 | <0,0001 | <0,0001 |
| Pesticides and biocide products, total of separate substances | mg/l | 0.0005 | <0.0001 | <0.0001 | <0.0001 |
| Carbonate hardness | °dH | – | 9.1 | 10.1 | 6.9 |
| Total hardness | °dH | –12.7 | 12.7 | 9.1 | |
| Total of alkaline earths | mol/m3 | 2.27 | 2.27 | 1.62 | |
| Hardness range | – | – | 2 medium |
2 medium |
2 medium |
| * The following applies to supply area 1: | Pipe 3 before Schönbühl reservoir 21.2 mg/l Pipes 1 and 2 before Schönbühl reservoir 25 mg/l Pipes 1–3 after Schönbühl reservoir 22 mg/l Stuttgart-Rotenberg reservoir 22 mg/l |
The analysed values only change marginally year to year.
The detergent and cleaning agents law of 29 April 2007 stipulates the following classification for identifying the hardness of drinking water:
soft: less than 1.5 mmol calcium carbonate/litre.
medium: 1.5 to 2.5 mmol calcium carbonate/litre.
hard: more than 2.5 mmol calcium carbonate/litre
The supply areas of the Landeswasserversorgung
Please click on the image to enlarge.