Water hardness and tap water in Wilhelmshaven

Name: Water hardness and tap water in Wilhelmshaven
Creator: Trinkwassermonitor
License: https://creativecommons.org/licenses/by/4.0/

Wilhelmshaven, Niedersachsen · Postcode 26382, 26384, 26386, 26389

This page is a translation of the German version; the German page is authoritative. German version · Report a translation error

Short answer: The tap water in Wilhelmshaven has a total hardness of 5.3 °dH, hardness range “soft” (as of 12 March 2026). All tested parameters with a legal limit (10) meet the limits set by the German Drinking Water Ordinance (TrinkwV). Source: test report by GEW Wilhelmshaven GmbH. WaterScore (provisional): 100 out of 100 – the test report contains only 2 of 7 core parameters.

Limits of the Drinking Water OrdinancemetAll tested parameters (10), at the waterworks
Water hardness5.3 °dH, softNo legal limit, only a range
Data coverageCore parameters: 2 of 7Score provisional

Verified drinking-water values

Parameter	Value	Limit (TrinkwV)	Sampling date	Source	Status
Nitrate	2.6 mg/L	50 mg/L	12 March 2026	GEW Wilhelmshaven GmbH	verified
Nitrite	< 0.01 mg/L	0.5 mg/L	12 March 2026	GEW Wilhelmshaven GmbH	verified
Chloride	32 mg/L 13 % of the limit	250 mg/L	12 March 2026	GEW Wilhelmshaven GmbH	verified
Sulphate	24 mg/L	250 mg/L	12 March 2026	GEW Wilhelmshaven GmbH	verified
Sodium	26 mg/L 13 % of the limit	200 mg/L	12 March 2026	GEW Wilhelmshaven GmbH	verified
Calcium	32 mg/L	–	12 March 2026	GEW Wilhelmshaven GmbH	verified
Magnesium	3.6 mg/L	–	12 March 2026	GEW Wilhelmshaven GmbH	verified
pH	8	6.5–9.5	12 March 2026	GEW Wilhelmshaven GmbH	verified
Total hardness	5.3 °dH (soft)	no legal limit	12 March 2026	GEW Wilhelmshaven GmbH	verified
Electrical conductivity	280 µS/cm	–	12 March 2026	GEW Wilhelmshaven GmbH	verified
Fluoride	< 0.03 mg/L	1.5 mg/L	12 March 2026	GEW Wilhelmshaven GmbH	verified
Iron	0.012 mg/L	0.2 mg/L	12 March 2026	GEW Wilhelmshaven GmbH	verified
Manganese	< 0.002 mg/L	0.05 mg/L	12 March 2026	GEW Wilhelmshaven GmbH	verified
Ammonium	< 0.02 mg/L	0.5 mg/L	12 March 2026	GEW Wilhelmshaven GmbH	verified

Note from the test report (in the German original): GEW veröffentlicht nur diese eine Analyse (Probenahmeort Klinikum Wilhelmshaven, versorgt aus den Wasserwerken Feldhausen und Klein-Horsten) als citywide-Wert; separate Werte je Wasserwerk oder Stadtteil (z. B. Sengwarden, Fedderwarden) sind nicht öffentlich verfügbar. Deutlich dünneres Parameter-Set als bei den meisten anderen Städten dieser Datenbank: Blei, Arsen, Uran, Kupfer, Quecksilber, PFAS, Trihalogenmethane und Mikrobiologie (Coliforme/E. coli) sind bei GEW nicht öffentlich publiziert - nicht als 'nicht nachweisbar' behauptet, sondern schlicht nicht verfügbar und daher hier weggelassen statt geschätzt.

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

Water at your own tap: The values describe the water the supplier delivers – not automatically the water at your tap. The water supplier is responsible up to the service connection (Hausanschluss); the building owner is responsible for the pipes beyond it. Lead can dissolve from lead pipes, leaded solder joints or old brass fittings, especially when water has stood in the pipes for a long time (stagnant water); this mainly affects buildings constructed before about 1973. If water has stood in the pipes for several hours, let it run until it comes out cool. If you suspect lead pipes, a lead analysis of the stagnant water by an accredited laboratory will help.

Background on household plumbing, not a measurement: in Wilhelmshaven, 61 % of buildings with living space were built before 1970, and a further 13 % 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 Wilhelmshaven

Nitrate 2.6 mg/L – about 5 % of the limit of 50 mg/L and in the unremarkable range. Boiling does not reduce nitrate.
pH 8 – 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 Wilhelmshaven in everyday life

At 5.3 °dH, Wilhelmshaven 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 Wilhelmshaven 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 Wilhelmshaven 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)

Values at the waterworks next to the maximum levels for bottled water “suitable for infant food”
Substance	Maximum level	Value in Wilhelmshaven
Sodium	20 mg/l	26 mg/l – above
Nitrate	10 mg/l	2.6 mg/l – not above
Nitrite	0.02 mg/l	below the detection limit (0.01 mg/l) – not above
Sulphate	240 mg/l	24 mg/l – not above
Fluoride	0.7 mg/l	below the detection limit (0.03 mg/l) – not above
Manganese	0.05 mg/l	below the detection limit (0.002 mg/l) – not above
Arsenic	0.005 mg/l	not in the report
Uranium	0.002 mg/l	not in the report

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 Wilhelmshaven

Can you drink the tap water in Wilhelmshaven?

According to the verified values, yes: All tested parameters with a legal limit (10) meet the limits set by the German Drinking Water Ordinance (TrinkwV). WaterScore (provisional): 100 out of 100 – the test report contains only 2 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 Wilhelmshaven?

The total hardness is 5.3 °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 Wilhelmshaven?

The published analysis by GEW Wilhelmshaven GmbH 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 Wilhelmshaven?

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

Total (provisional)100 / 100
Chemical safety100 / 100
Nutrients100 / 100
General parameters100 / 100
Data timeliness100 / 100
Data quality100 / 100

Data coverage: 2 of 7 core parameters. Not in the test report: Lead, Copper, Arsenic, Uranium and PFAS (sum). Missing parameters are neither estimated nor counted as harmless: the score is based only on the values available and is therefore provisional. 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 (Probeentnahme Klinikum Wilhelmshaven) (GEW Wilhelmshaven GmbH)

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

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

Data as of: 12 March 2026 · verified: 14 of 14 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 Wilhelmshaven. Retrieved from https://trinkwassermonitor.ink/en/tap-water/wilhelmshaven/.”