Water hardness and tap water in Rastatt
Landkreis Rastatt, Baden-Württemberg · Postcode 76437
This page is a translation of the German version; the German page is authoritative. German version · Report a translation error
- Limits of the Drinking Water OrdinancemetAll tested parameters (9), at the waterworks
- Water hardness10.4 °dH, mediumNo legal limit, only a range
- Data coverageCore parameters: 2 of 7Score provisional
Verified drinking-water values
Note from the test report (in the German original): Trinkwasseranalyse 2026 der Stadtwerke Rastatt (Stand 10.03.2026; Probenahme und Analyse durch das Technologiezentrum Wasser Karlsruhe), Werte des Wasserwerks Ottersdorf am Reinwasserabgang. Laut Stadtwerken liegt die Härte in der Kernstadt und den Ortsteilen Ottersdorf, Plittersdorf, Wintersdorf, Niederbühl und Förch bei rund 10,4 °dH; Förch selbst wird aus dem Wasserwerk Förch des Wasserversorgungsverbunds Vorderes Murgtal versorgt, für das diese Analyse keine Werte enthält. Für Rauental und das Industriegebiet nennen die Stadtwerke die Härte des Wasserwerks Rauental (9,6 °dH, ebenfalls mittel). Dessen Wasser enthält deutlich mehr Nitrat (31,4 statt 2,1 mg/l); die Summe PFAS-20 liegt dort bei 0,034 µg/l, die Summe PFAS-4 bei 0,000 µg/l. Es wird aufgehärtet, damit es sich im Netz mit dem Ottersdorfer Wasser mischen lässt. Beide Werke entfernen PFAS mit Aktivkohlefiltern (Rauental seit 2018, Ottersdorf seit Juli 2024). Die Summe PFAS-4 lag in Ottersdorf bei 0,001 µg/l; ab dem 12.01.2028 gilt dafür ein Grenzwert von 0,02 µg/l. Blei, Kupfer, Arsen, Uran, Nitrit und mikrobiologische Werte enthält die veröffentlichte Analyse nicht; den ausführlichen Prüfbericht geben die Stadtwerke auf Anfrage heraus.
Background on household plumbing, not a measurement: in Rastatt, 49 % of buildings with living space were built before 1970, and a further 14 % between 1970 and 1979 (Zensus 2022, Statistisches Bundesamt, dl-de/by-2-0). (Zensus 2022) According to the German Environment Agency (Umweltbundesamt), lead pipes exist at most in houses built before 1973 – and by no means in all of them. Whether there are any in your house is known to the owner or a plumber. (UBA)
What the values mean for Rastatt
- Nitrate 2.1 mg/L – about 4 % of the limit of 50 mg/L and in the unremarkable range. Boiling does not reduce nitrate.
- PFAS (sum of PFAS-20) 33 ng/L – about 33 % of the limit of 100 ng/L (since 12 January 2026).
- pH 8.07 – within the range of the Drinking Water Ordinance (6.5 to 9.5). The pH determines how corrosive the water is in household plumbing.
Water hardness in Rastatt in everyday life
At 10.4 °dH, Rastatt is in the hardness range “medium” (soft: below 8.4 °dH, medium: 8.4–14 °dH, hard: above 14 °dH).
- Dose detergent for the hardness range “medium”.
- As a rule of thumb, descale the kettle about every four to six weeks and the coffee machine as the manufacturer recommends.
- A limescale protection device is not a must at medium hardness; regular descaling is often enough.
Baby food and low sodium: tap water in Rastatt next to the bottled-water thresholds
Bottled water may only be labelled “suitable for preparing infant food” („geeignet für die Zubereitung von Säuglingsnahrung“) if it keeps to the maximum levels of the German Mineral and Table Water Ordinance (Mineral- und Tafelwasser-Verordnung, Annex 6). Here the published values for Rastatt are shown next to them, each substance on its own. This is a comparison with labelling thresholds for bottled water, not a statement on whether your tap water is suitable for baby food. (Min/TafelWV, Anlage 6)
| Substance | Maximum level | Value in Rastatt |
|---|---|---|
| Sodium | 20 mg/l | 13 mg/l – not above |
| Nitrate | 10 mg/l | 2.1 mg/l – not above |
| Nitrite | 0.02 mg/l | not in the report |
| Sulphate | 240 mg/l | 33 mg/l – not above |
| Fluoride | 0.7 mg/l | not in the report |
| Manganese | 0.05 mg/l | below the detection limit (0.005 mg/l) – not above |
| Arsenic | 0.005 mg/l | not in the report |
| Uranium | 0.002 mg/l | not in the report |
Against the other thresholds of Annex 6, the water would qualify as: low in sodium (“suitable for a low-sodium diet”) (Sodium 13 mg/l, threshold below 20 mg/l).
For context: the German Environment Agency (Umweltbundesamt) considers preparing baby food with bottled water carrying this label necessary only in rare cases, for example when tap water is temporarily allowed to contain more than 50 mg/l nitrate. (UBA 2016, p. 59) Water from lead pipes in the house is always unsuitable for infants. (UBA 2020, p. 16) The values apply at the waterworks. Questions about baby food are answered by your midwife, your paediatrician and the health office (Gesundheitsamt).
Frequently asked questions about tap water in Rastatt
Can you drink the tap water in Rastatt?
According to the verified values, yes: All tested parameters with a legal limit (9) meet the limits set by the German Drinking Water Ordinance (TrinkwV). WaterScore (provisional): 100 out of 100 – the test report contains only 2 of 7 core parameters. This applies to the water from the waterworks – restrictions can only arise from old household plumbing.
How hard is the water in Rastatt?
The total hardness is 10.4 °dH – hardness range “medium”. Dose detergent for the hardness range “medium”.
Is there PFAS in the tap water in Rastatt?
Yes, in measurable amounts: according to the published analysis by Stadtwerke Rastatt (as of 10 March 2026), the sum of PFAS-20 is 0.033 µg/l – that is 33 % of the limit of 0.1 µg/l, which has applied since 12 January 2026. Whether the limit of 0.02 µg/l for the sum of PFAS-4, which applies from 12 January 2028, is met cannot be read from the sum of PFAS-20.
Do I need to filter my tap water in Rastatt?
Based on the verified supplier values, a filter is not necessary. It can make sense if you do not like the taste. If you suspect lead pipes in an old building, a filter does not help; a laboratory analysis at the tap does – that is a question of the household plumbing, not of the water leaving the works.
WaterScore
- Total (provisional)100 / 100
- Chemical safety100 / 100
- PFAS100 / 100
- Nutrients100 / 100
- General parameters100 / 100
- Data timeliness100 / 100
- Data quality100 / 100
Data coverage: 2 of 7 core parameters. Not in the test report: Nitrite, Lead, Copper, Arsenic and Uranium. Missing parameters are neither estimated nor counted as harmless: the score is based only on the values available and is therefore provisional. It is not a health assessment and says nothing about the water beyond the service connection. Methodology v3: how we calculate the WaterScore.
Evidence: cite and check
- Trinkwasseranalyse 2026 (Stand 10.03.2026), Wasserwerk Ottersdorf, Reinwasserabgang (Stadtwerke Rastatt GmbH (Probenahme und Analyse: Technologiezentrum Wasser, Karlsruhe))
Suggested citation: Trinkwassermonitor (2026): Tap water in Rastatt. Values according to the water supplier’s test report, sampling date 10 March 2026; at the waterworks, not household plumbing. https://trinkwassermonitor.ink/en/tap-water/rastatt/
JSON: /api/v1/evidence?city=rastatt
Data as of: 10 March 2026 · verified: 13 of 13 evaluated parameters.
This page shows only verified test data with sources, or states explicitly where data is missing (no estimated values). Cite as: “Trinkwassermonitor (2026). Tap water in Rastatt. Retrieved from https://trinkwassermonitor.ink/en/tap-water/rastatt/.”