Water hardness and tap water in Kassel

Kassel, Hessen · Postcode 34117, 34119, 34121, 34125, 34127

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 (8), at the waterworks
• Water hardness14.58 °dH, hardNo legal limit, only a range
• Data coverageCore parameters: 4 of 7Score based on complete data

Verified drinking-water values

Note from the test report (in the German original): Städtische Werke Kassel (KASSELWASSER) · Verbraucherinformation nach §45 TrinkwV, Hochbehälter Bergfreiheit (Probenahme 22.10.2024) – einer von 14 einzeln geprüften Hochbehältern/Versorgungszonen in Kassel und Vellmar. Die Zonen unterscheiden sich stark: Hochbehälter Hessenschanze misst mit 4,50 °dH das weichste Wasser der Stadt (Probenahme 12.03.2024, Uran 0,0083 mg/l), während andere Zonen wie Bergfreiheit im harten Bereich liegen (Härtestufe III). PFAS wird in diesem Dokument nicht als Parameter geführt.

Is a value wrong or out of date? Report an error – we check every report against the original source.

Background on household plumbing, not a measurement: in Kassel, 65 % of buildings with living space were built before 1970, and a further 11 % 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 Kassel

• Nitrate 17 mg/L – about 34 % 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.
• 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 3.1 µg/L – within the checked range against a limit of 10 µg/L. In some regions uranium occurs naturally from the rock (geogenic).
• pH 7.86 – 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 Kassel in everyday life

At 14.58 °dH, Kassel 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 Kassel 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 Kassel 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)

Against the other thresholds of Annex 6, the water would qualify as: low in sodium (“suitable for a low-sodium diet”) (Sodium 16.09 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 Kassel

WaterScore

• Total96.3 / 100
• Chemical safety100 / 100
• Heavy metals100 / 100
• Nutrients100 / 100
• General parameters100 / 100
• Data timeliness80.1 / 100
• Data quality100 / 100

Data coverage: 4 of 7 core parameters. Not in the test report: Nitrite, Arsenic and PFAS (sum). 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

• Trinkwasserversorgung Kassel und Vellmar, Verbraucherinformation nach §45 TrinkwV, Hochbehälter Bergfreiheit, Probenahme 22.10.2024 (Städtische Werke Kassel (KASSELWASSER)) · SHA-256 of the evaluated file: 55f9eb1ba69fefa7…, checked on 3 October 2026

Suggested citation: Trinkwassermonitor (2024): Tap water in Kassel. Values according to the water supplier’s test report, sampling date 22 October 2024; at the waterworks, not household plumbing. https://trinkwassermonitor.ink/en/tap-water/kassel/

JSON: /api/v1/evidence?city=kassel

Data as of: 22 October 2024 · verified: 12 of 12 evaluated parameters. (older than twelve months – under § 46 TrinkwV your supplier must publish current values online)

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 Kassel. Retrieved from https://trinkwassermonitor.ink/en/tap-water/kassel/.”

Further information

• German version: Trinkwasser in Kassel
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