Water hardness and tap water in Frankfurt am Main

Frankfurt am Main, Hessen · Postcode 60306, 60311, 60486, 60594, 60598

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 hardness13.9 °dH, mediumNo 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): Mainova/Hessenwasser · Frankfurt hat kein zentrales Analyse-PDF, sondern ein adressbasiertes Nachschlage-Tool mit mehreren Versorgungszonen; hier Zone Sachsenhausen/Oberrad (SR), Schwankungsbreite der Einzelmessungen 2025 (verwendeter Wert ist der Mittelpunkt der vom Versorger genannten Spanne, kein einzelner Originalwert). Drei weitere geprüfte Zonen weichen ab: Nieder-Erlenbach (ER, 10,2–12,9 °dH), Nord (OV, 10,0–11,9 °dH, niedrigste PFAS-Werte der Stadt: 0,000001–0,000002 mg/l) und Friedberger Landstraße (FRIL, 9,8–11,7 °dH). Zone SR hat mit bis zu 0,000055 mg/l (55 ng/l) den höchsten gemessenen PFAS-20-Einzelwert der vier geprüften Zonen, liegt aber weiterhin klar unter dem seit 12.01.2026 geltenden Grenzwert von 100 ng/l. Der Wert für eine bestimmte Adresse lässt sich direkt bei Mainova abfragen.

Is a value wrong or out of date?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 Frankfurt am Main, 68 % of buildings with living space were built before 1970, and a further 7 % 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 Frankfurt am Main

• Nitrate 7.9 mg/L – about 16 % of the limit of 50 mg/L and in the unremarkable range. Boiling does not reduce nitrate.
• PFAS (sum of PFAS-20) 31 ng/L – about 31 % 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 0.35 µg/L – unremarkable against a limit of 10 µg/L. In some regions uranium occurs naturally from the rock (geogenic).
• pH 7.64 – 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 Frankfurt am Main in everyday life

At 13.9 °dH, Frankfurt am Main 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 Frankfurt am Main 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 Frankfurt am Main 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)

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 Frankfurt am Main

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

• Wasserqualität und Wasserhärte Frankfurt am Main, Versorgungszone Sachsenhausen/Oberrad (SR), Schwankungsbreite 2025 (Mainova AG / Hessenwasser GmbH & Co. KG)

Suggested citation: Trinkwassermonitor (2025): Tap water in Frankfurt am Main. Values according to the water supplier’s test report, sampling date 2025; at the waterworks, not household plumbing. https://trinkwassermonitor.ink/en/tap-water/frankfurt-am-main/

JSON: /api/v1/evidence?city=frankfurt-am-main

Data as of: 2025 · 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 Frankfurt am Main. Retrieved from https://trinkwassermonitor.ink/en/tap-water/frankfurt-am-main/.”

Further information

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