Water hardness and tap water in Passau

Passau, Bayern · Postcode 94032, 94034, 94036

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 (16), at the waterworks
• Water hardness10.6 °dH, mediumNo legal limit, only a range
• Data coverageCore parameters: 7 of 7Score based on complete data

Verified drinking-water values

Note from the test report (in the German original): Stadtwerke Passau · Trinkwasser-Analysewerte für das Wassergewinnungsgebiet „Insel Soldatenau“ (Grundwasser aus dem Begleitstrom des Inns), aus dem die Stadt Passau versorgt wird. Das Dokument nennt nur das Datum „Stand: 12. Mai 2026“, kein gesondertes Probenahmedatum. Schwermetalle (Blei, Arsen, Uran, Kupfer, Quecksilber), Fluorid und Trihalogenmethane enthält dieser Bericht nicht; für sie gelten weiter die Werte aus dem Bericht vom 25.08.2025. Mikrobiologische Werte (coliforme Bakterien, E. coli) weist der Bericht nicht aus. Tiefenbach und Salzweg sind eigenständige, von den Stadtwerken Passau mitversorgte Gemeinden mit eigenen Zonen und nicht Teil dieses Datensatzes. Bericht der Stadtwerke Passau mit „Stand: 25.08.2025“ für dasselbe Wassergewinnungsgebiet „Insel Soldatenau“. Hier nur die Stoffe, die der neuere Bericht vom Mai 2026 nicht enthält (Schwermetalle, Fluorid, Trihalogenmethane). Die Untersuchungen sind akkreditiert (D-PL-14519-01-00, D-PL-18961-01-00), ein Laborname ist nicht angegeben.

Is a value wrong or out of date?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 Passau, 43 % of buildings with living space were built before 1970, and a further 17 % 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 Passau

• Nitrate 5.7 mg/L – about 11 % of the limit of 50 mg/L and in the unremarkable range. Boiling does not reduce nitrate.
• PFAS (sum of PFAS-20) 4 ng/L – about 4 % 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 – not detectable at the waterworks (limit 10 µg/L).
• pH 7.68 – 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 Passau in everyday life

At 10.6 °dH, Passau 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 Passau 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 Passau 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 13.4 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 Passau

WaterScore

• Total100 / 100
• Chemical safety100 / 100
• Heavy metals100 / 100
• PFAS100 / 100
• Nutrients100 / 100
• General parameters100 / 100
• Data timeliness100 / 100
• Data quality100 / 100

Data coverage: 7 of 7 core parameters. 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

• Trinkwasser-Analysewerte Wassergewinnungsgebiet „Insel Soldatenau“, Stand 12. Mai 2026 (Stadtwerke Passau GmbH) · SHA-256 of the evaluated file: ce00811cfc3adbf6…, checked on 3 October 2026
• Trinkwasser-Analysewerte Wassergewinnungsgebiet 'Insel Soldatenau' (Stadtwerke Passau GmbH) · SHA-256 of the evaluated file: 401426ffe9f592eb…, checked on 3 October 2026

Suggested citation: Trinkwassermonitor (2026): Tap water in Passau. Values according to the water supplier’s test report, sampling date 12 May 2026; at the waterworks, not household plumbing. https://trinkwassermonitor.ink/en/tap-water/passau/

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

Data as of: 12 May 2026 · verified: 25 of 25 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 Passau. Retrieved from https://trinkwassermonitor.ink/en/tap-water/passau/.”

Further information

• German version: Trinkwasser in Passau
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