Water hardness and tap water in Oberhausen
Oberhausen, Nordrhein-Westfalen · Postcode 46045, 46047, 46049, 46117, 46119, 46145 …
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 hardness8 °dH, softNo legal limit, only a range
- Data coverageCore parameters: 6 of 7Score based on complete data
Verified drinking-water values
Note from the test report (in the German original): Diese Werte gelten für den Versorgungsbereich der Wasserwerke Mülheim-Styrum-Ost und Mülheim-Styrum-West, der laut RWW den größeren Teil Oberhausens abdeckt (südlich der A42, sowie nördlich A42/westlich A516-A3). Der nordöstliche Teil Oberhausens wird stattdessen vom Wasserwerk Dorsten-Holsterhausen versorgt und hat spürbar härteres Wasser (Median-Gesamthärte 13,5 °dH statt 8,0 °dH); welcher Bevölkerungsanteil genau in diesem Gebiet liegt, ließ sich nicht verifizieren. RWW veröffentlicht die Daten je Wasserwerk/Versorgungsbereich, nicht je Stadt – derselbe Versorgungsbereich beliefert auch Mülheim an der Ruhr und Teile Bottrops, weshalb Oberhausen und Mülheim hier dieselbe Quelle und identische Messwerte teilen. Berichtszeitraum ist das volle Jahr 2025 (Median/Niedrigst-/Höchstwert aus Einzelanalysen). Mikrobiologische Parameter (coliforme Keime) sind in diesem Dokument nicht enthalten. PFAS-Werte werden von RWW laut eigener Aussage 'deutlich unter den Grenzwerten' gemessen, aber ohne öffentlich als Text zugängliche Zahlenwerte (nur als Grafik) – daher hier nicht aufgeführt.
Background on household plumbing, not a measurement: in Oberhausen, 63 % of buildings with living space were built before 1970, and a further 10 % 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 Oberhausen
- Nitrate 8.7 mg/L – about 17 % of the limit of 50 mg/L and in the unremarkable range. 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 – not detectable at the waterworks (limit 10 µg/L).
- pH 7.78 – 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 Oberhausen in everyday life
At 8 °dH, Oberhausen is in the hardness range “soft” (soft: below 8.4 °dH, medium: 8.4–14 °dH, hard: above 14 °dH).
- Dose detergent for the hardness range “soft” – the lowest amount on the pack.
- Limescale deposits are rare; kettles and coffee machines only need descaling every few months.
- At this hardness you do not need limescale protection or a water softener.
Baby food and low sodium: tap water in Oberhausen 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 Oberhausen 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 Oberhausen |
|---|---|---|
| Sodium | 20 mg/l | 55.8 mg/l – above |
| Nitrate | 10 mg/l | 8.7 mg/l – not above |
| Nitrite | 0.02 mg/l | below the detection limit (0.01 mg/l) – not above |
| Sulphate | 240 mg/l | 47 mg/l – not above |
| Fluoride | 0.7 mg/l | below the detection limit (0.2 mg/l) – not above |
| Manganese | 0.05 mg/l | below the detection limit (0.005 mg/l) – not above |
| Arsenic | 0.005 mg/l | below the detection limit (0.001 mg/l) – not above |
| Uranium | 0.002 mg/l | below the detection limit (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 Oberhausen
Can you drink the tap water in Oberhausen?
According to the verified values, yes: All tested parameters with a legal limit (16) meet the limits set by the German Drinking Water Ordinance (TrinkwV). WaterScore: 100 out of 100 (data coverage: 6 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 Oberhausen?
The total hardness is 8 °dH – hardness range “soft”. Dose detergent for the hardness range “soft” – the lowest amount on the pack.
Is there PFAS in the tap water in Oberhausen?
The published analysis by RWW that we evaluated gives no PFAS value. This does not mean there is no PFAS in the water; there is simply no figure for it. Since 12 January 2026, a limit of 0.1 µg/l has applied to the sum of PFAS-20. The supplier can tell you whether PFAS was measured and with what result.
Do I need to filter my tap water in Oberhausen?
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
- Nutrients100 / 100
- General parameters100 / 100
- Data timeliness100 / 100
- Data quality100 / 100
Data coverage: 6 of 7 core parameters. Not in the test report: 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
- Trinkwasserdaten 2025 – Wasserwerke Mülheim-Styrum-Ost/West (RWW Rheinisch-Westfälische Wasserwerksgesellschaft mbH) · SHA-256 of the evaluated file: 70f2ab24e74873d8…, checked on 3 October 2026
Suggested citation: Trinkwassermonitor (2025): Tap water in Oberhausen. Values according to the water supplier’s test report, sampling date 2025; at the waterworks, not household plumbing. https://trinkwassermonitor.ink/en/tap-water/oberhausen/
JSON: /api/v1/evidence?city=oberhausen
Data as of: 2025 · verified: 20 of 20 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 Oberhausen. Retrieved from https://trinkwassermonitor.ink/en/tap-water/oberhausen/.”