Water hardness and tap water in Heidelberg
Heidelberg, Baden-Württemberg · Postcode 69115, 69117, 69118, 69120, 69121
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 hardness19.8 °dH, hardNo legal limit, only a range
- Data coverageCore parameters: 5 of 7Score based on complete data
Verified drinking-water values
Note from the test report (in the German original): Stadtwerke Heidelberg (Netze) · Stand 28.01.2026, Zone 'Hartwasserzone südlich des Neckars' (Wasserwerke Rauschen, Schwetzinger Hardt, Neckargruppe) – eine von vier Heidelberger Versorgungszonen; für die übrigen Zonen (u. a. eine weichere Zone nördlich des Neckars) liegen uns keine geprüften Zahlen vor. Werte als Mittelwert mit Bandbreite (Minimum–Maximum über den Berichtszeitraum) angegeben.
Background on household plumbing, not a measurement: in Heidelberg, 62 % of buildings with living space were built before 1970, and a further 9 % 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 Heidelberg
- Nitrate 14 mg/L – about 28 % of the limit of 50 mg/L and in the medium range – such values occur in catchments shaped by agriculture. Boiling does not reduce nitrate.
- PFAS (sum of PFAS-20) 18 ng/L – about 18 % of the limit of 100 ng/L (since 12 January 2026).
- Lead – not detectable at the waterworks. Lead gets into the water almost only through old lead pipes in household plumbing, not via the supplier.
- Uranium 0.5 µg/L – unremarkable against a limit of 10 µg/L. In some regions uranium occurs naturally from the rock (geogenic).
- pH 7.3 – 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 Heidelberg in everyday life
At 19.8 °dH, Heidelberg is in the hardness range “hard” (soft: below 8.4 °dH, medium: 8.4–14 °dH, hard: above 14 °dH).
- Dose detergent for the hardness range “hard” – a larger amount is needed; a water softener for the washing machine can save detergent.
- Limescale builds up quickly: descale the kettle about every two to three weeks, and taps and shower heads too.
- In your own house, limescale protection or a water softener can be worthwhile at this hardness; in a rented flat, the owner decides.
Baby food and low sodium: tap water in Heidelberg 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 Heidelberg 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 Heidelberg |
|---|---|---|
| Sodium | 20 mg/l | 25 mg/l – above |
| Nitrate | 10 mg/l | 14 mg/l – above |
| Nitrite | 0.02 mg/l | not in the report |
| Sulphate | 240 mg/l | 83 mg/l – not above |
| Fluoride | 0.7 mg/l | not in the report |
| Manganese | 0.05 mg/l | not in the report |
| Arsenic | 0.005 mg/l | not in the report |
| Uranium | 0.002 mg/l | 0.0005 mg/l – not above |
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 Heidelberg
Can you drink the tap water in Heidelberg?
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: 100 out of 100 (data coverage: 5 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 Heidelberg?
The total hardness is 19.8 °dH – hardness range “hard”. Dose detergent for the hardness range “hard” – a larger amount is needed; a water softener for the washing machine can save detergent.
Is there PFAS in the tap water in Heidelberg?
Yes, in measurable amounts: according to the published analysis by Stadtwerke Heidelberg (as of 28 January 2026), the sum of PFAS-20 is 0.018 µg/l – that is 18 % of the limit of 0.1 µg/l, which has applied since 12 January 2026.
Do I need to filter my tap water in Heidelberg?
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
- Total100 / 100
- Chemical safety100 / 100
- Heavy metals100 / 100
- PFAS100 / 100
- Nutrients100 / 100
- General parameters100 / 100
- Data timeliness100 / 100
- Data quality100 / 100
Data coverage: 5 of 7 core parameters. Not in the test report: Nitrite and Arsenic. Missing parameters are neither estimated nor counted as harmless: the score is based only on the values available. 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 Heidelberg, Hartwasserzone südlich des Neckars, Stand 28.01.2026 (Stadtwerke Heidelberg (Stadtwerke Heidelberg Netze)) · SHA-256 of the evaluated file: 076cc679145807f7…, checked on 3 October 2026
Suggested citation: Trinkwassermonitor (2026): Tap water in Heidelberg. Values according to the water supplier’s test report, sampling date 28 January 2026; at the waterworks, not household plumbing. https://trinkwassermonitor.ink/en/tap-water/heidelberg/
JSON: /api/v1/evidence?city=heidelberg
Data as of: 28 January 2026 · verified: 15 of 15 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 Heidelberg. Retrieved from https://trinkwassermonitor.ink/en/tap-water/heidelberg/.”