Water hardness and tap water in Offenbach am Main
Offenbach am Main, Hessen · Postcode 63065, 63067, 63069, 63071, 63073
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 (13), at the waterworks
- Water hardness11.7 °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): Zweckverband Wasserversorgung Stadt und Kreis Offenbach (ZWO) · Berichtsstand 16.07.2026, Messwerte 2. Quartal 2026, Versorgungsgebiet 7 (Offenbach am Main, ausgenommen die Stadtteile Hafen, Kaiserlei und nördliches Nordend, die in anderen Versorgungsgebieten liegen). Werte als Spannbreite über den Berichtszeitraum angegeben (hier: Mittelpunkt verwendet). Nicht OVAG, sondern der ZWO ist für die Stadt Offenbach zuständig.
Background on household plumbing, not a measurement: in Offenbach am Main, 63 % 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 Offenbach am Main
- Nitrate 20.45 mg/L – about 41 % of the limit of 50 mg/L and comparatively high for a city waterworks; the cause is usually nitrate from agriculture entering the raw water. Boiling does not reduce nitrate.
- PFAS (sum of PFAS-20) 19 ng/L – about 19 % 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 7.77 – 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 Offenbach am Main in everyday life
At 11.7 °dH, Offenbach 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 Offenbach 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 Offenbach 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)
| Substance | Maximum level | Value in Offenbach am Main |
|---|---|---|
| Sodium | 20 mg/l | 16.3 mg/l – not above |
| Nitrate | 10 mg/l | 20.45 mg/l – above |
| Nitrite | 0.02 mg/l | not in the report |
| Sulphate | 240 mg/l | 72.1 mg/l – not above |
| Fluoride | 0.7 mg/l | 0.0695 mg/l – not above |
| Manganese | 0.05 mg/l | below the detection limit (0.01 mg/l) – not above |
| Arsenic | 0.005 mg/l | not in the report |
| Uranium | 0.002 mg/l | below the detection limit (0.0005 mg/l) – not above |
Against the other thresholds of Annex 6, the water would qualify as: low in sodium (“suitable for a low-sodium diet”) (Sodium 16.3 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 Offenbach am Main
Can you drink the tap water in Offenbach am Main?
According to the verified values, yes: All tested parameters with a legal limit (13) 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 Offenbach am Main?
The total hardness is 11.7 °dH – hardness range “medium”. Dose detergent for the hardness range “medium”.
Is there PFAS in the tap water in Offenbach am Main?
Yes, in measurable amounts: according to the published analysis by ZWO Zweckverband Wasserversorgung Offenbach (as of 16 July 2026), the sum of PFAS-20 is 0.019 (upper end of the range given by the supplier) µg/l – that is 19 % of the limit of 0.1 µg/l, which has applied since 12 January 2026. Even this sum of all 20 substances is below the limit of 0.02 µg/l that applies from 12 January 2028 to the sum of four of them (PFAS-4).
Do I need to filter my tap water in Offenbach am Main?
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.
Is the nitrate level in Offenbach am Main a concern?
The value of 20.45 mg/L is below the limit of 50 mg/L, but higher than in many other evaluated cities. The limit of the Drinking Water Ordinance also applies to preparing baby food; mineral water labelled “suitable for preparing infant food” („geeignet für die Zubereitung von Säuglingsnahrung“) may contain at most 10 mg/L nitrate. Boiling does not help against nitrate.
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 Offenbach am Main, Versorgungsgebiet 7, 2. Quartal 2026 (Zweckverband Wasserversorgung Stadt und Kreis Offenbach (ZWO)) · SHA-256 of the evaluated file: 402e151b908d0437…, checked on 3 October 2026
Suggested citation: Trinkwassermonitor (2026): Tap water in Offenbach am Main. Values according to the water supplier’s test report, sampling date 16 July 2026; at the waterworks, not household plumbing. https://trinkwassermonitor.ink/en/tap-water/offenbach-am-main/
JSON: /api/v1/evidence?city=offenbach-am-main
Data as of: 16 July 2026 · verified: 23 of 23 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 Offenbach am Main. Retrieved from https://trinkwassermonitor.ink/en/tap-water/offenbach-am-main/.”