Water hardness in Wilhelmshaven
5.7 °dH moderately hard
Tap water in Wilhelmshaven is moderately hard: 5.7 °dH (102 mg/L · 5.9 gpg · 10.2 °fH).
Source: OOWV Trinkwasseranalyse für das Versorgungsgebiet Wasserwerk Sandelermöns, 1. Quartal 2026 (Prüfbericht 26-02098) (2026-01) · data checked 2026-10-21
Range across supply zones: 100–104 mg/L.
2 supply zones — hardness varies by neighbourhood; the figure above is the median.
Hardness by district / supply zone
| °dH | mg/L | ||
|---|---|---|---|
| Randbereiche, Wasserwerk Harlingerland (OOWV) | 5.6 | 100 | moderately hard |
| Randbereiche, Wasserwerk Sandelermöns (OOWV) | 5.8 | 104 | moderately hard |
The value of 101.7 mg/L CaCO₃ is taken from the OOWV analysis for the Sandelermöns waterworks supply area (first quarter 2026), with two zones between 100.0 and 103.5 mg/L. OOWV serves only the edge areas of the city, and we have not identified the main supplier, so this is indicative. Nearby Jever and Schortens show the same 101.7 mg/L, while Jade is harder at 133.9 mg/L.
German law (WRMG) uses 3 bands: soft < 8.4 °dH, medium 8.4–14 °dH, hard > 14 °dH.
Water data
| Total hardness | 5.7 °dH |
|---|---|
| Utility | OOWV (Oldenburgisch-Ostfriesischer Wasserverband), edge areas only; main supplier not identified |
How Wilhelmshaven compares
- Tap water in Wilhelmshaven is 50 % softer than the median of the 809 cities we track in Germany (11.5 °dH).
- By hardness it ranks 707 of 809 in Germany (1 = hardest); 12 % of these cities have softer water.
- In Niedersachsen it is number 79 of 94 cities; the regional median is 7 °dH.
- Nearest city with clearly harder water: Jade, 23 km away (7.5 °dH).
Ranking of the hardest and softest water in Germany →
What it means at home
- Visible kettle scale every few weeks; vinegar or citric acid is enough.
- Water heater and washing machine: some long-term scale; a scale inhibitor slows it.
- Dishwasher: medium salt setting.
- Softener optional; pays off mainly with a gas boiler or tankless heater.
How much salt will you use for softening?
Optional. A scale inhibitor or a small softener protects the heater; soap savings are modest.
Descale a coffee machine or kettle about every 3 months (typical manufacturer guidance for this hardness).
Estimates for planning, not a quote. Check your appliance manual for exact settings.
Dishwasher setting in Wilhelmshaven
| Brand | Setting for this water |
|---|---|
| Bosch | H00 |
| Miele | 6 °dH |
| AEG / Electrolux | 2 |
| Beko | 2nd |
| Hoover | S1 |
| LG | H1 |
From each brand's manual for the model family named in the source; your model may differ, so check its manual. All brands and how to change the setting →
FAQ
Is Wilhelmshaven water hard or soft?
It is moderately hard: 102 mg/L as CaCO₃ (5.9 gpg, 5.7 °dH). The usual bands are soft < 60, moderately hard 60–120, hard 120–180 and very hard > 180 mg/L.
Is tap water in Wilhelmshaven safe to drink?
Hardness is not a health issue; it is about limescale, taste and appliances. Mains water must meet national drinking-water standards. German law (WRMG) uses 3 bands: soft < 8.4 °dH, medium 8.4–14 °dH, hard > 14 °dH.
How many grains per gallon is Wilhelmshaven water?
5.9 gpg, equal to 5.7 °dH, 10.2 °fH or 102 mg/L calcium carbonate.
What dishwasher salt setting should I use in Wilhelmshaven?
For 102 mg/L (5.7 °dH) check your manufacturer's table: level 2–3.
Do I need a water softener in Wilhelmshaven?
Not essential; a scale inhibitor protects the heater cheaply.
Source
Source: OOWV Trinkwasseranalyse für das Versorgungsgebiet Wasserwerk Sandelermöns, 1. Quartal 2026 (Prüfbericht 26-02098) (2026-01). Method: figure published by the water supplier. OOWV Trinkwasseranalyse für das Versorgungsgebiet Wasserwerk Sandelermöns, 1. Quartal 2026 (Prüfbericht 26-02098) · Outdated figure? Tell us