Water hardness in Düsseldorf
15 °dH very hard
Tap water in Düsseldorf is very hard: 15 °dH (268 mg/L · 15.6 gpg · 26.8 °fH).
Source: Stadtwerke Düsseldorf - Trinkwasseranalyse 2026 (Auswertung Zeitraum 01.01.2025-31.12.2025) (2025) · data checked 2026-10-19
Stadtwerke Düsseldorf reports a single figure of 267.8 mg/L CaCO₃ from its 2025 evaluation and states that it applies to the whole supply area, which also includes Mettmann. The analysis is based on samples from one reservoir, so small local differences are possible. Under the German WRMG, utilities must also publish the hardness range, so you can cross-check with their notice.
German law (WRMG) uses 3 bands: soft < 8.4 °dH, medium 8.4–14 °dH, hard > 14 °dH.
Water data
| Total hardness | 15 °dH |
|---|---|
| Utility | Stadtwerke Düsseldorf |
How Düsseldorf compares
- Tap water in Düsseldorf is 30 % harder than the median of the 809 cities we track in Germany (11.5 °dH).
- By hardness it ranks 258 of 809 in Germany (1 = hardest); 68 % of these cities have softer water.
- In Nordrhein-Westfalen it is number 26 of 153 cities; the regional median is 11.3 °dH.
- Nearest city with clearly softer water: Hilden, 13 km away (11 °dH).
- Nearest city with clearly harder water: Ratingen, 10 km away (19.1 °dH).
Ranking of the hardest and softest water in Germany →
What it means at home
- Severe scale: heater elements and washing-machine heaters fail early.
- Detergent use is very high; taps and screens coat within days.
- Dishwasher at maximum salt setting.
- An ion-exchange softener is practically essential; RO for drinking water.
How much salt will you use for softening?
Yes. At this hardness a softener pays for itself through appliance life and detergent.
Descale a coffee machine or kettle about every 1 months (typical manufacturer guidance for this hardness).
Estimates for planning, not a quote. Check your appliance manual for exact settings.
Dishwasher setting in Düsseldorf
| Brand | Setting for this water |
|---|---|
| Bosch | H04 |
| Miele | 15 °dH |
| AEG / Electrolux | 4 |
| Beko | 4th |
| Hoover | S2 |
| LG | H3 |
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 Düsseldorf water hard or soft?
It is very hard: 268 mg/L as CaCO₃ (15.6 gpg, 15 °dH). The usual bands are soft < 60, moderately hard 60–120, hard 120–180 and very hard > 180 mg/L.
Is tap water in Düsseldorf 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 Düsseldorf water?
15.6 gpg, equal to 15 °dH, 26.8 °fH or 268 mg/L calcium carbonate.
What dishwasher salt setting should I use in Düsseldorf?
For 268 mg/L (15 °dH) check your manufacturer's table: maximum level (5–7).
Do I need a water softener in Düsseldorf?
Yes, unless you are only passing through: scale damages appliances within a few years.
Source
Source: Stadtwerke Düsseldorf - Trinkwasseranalyse 2026 (Auswertung Zeitraum 01.01.2025-31.12.2025) (2025). Method: figure published by the water supplier. Stadtwerke Düsseldorf - Trinkwasseranalyse 2026 (Auswertung Zeitraum 01.01.2025-31.12.2025) · Outdated figure? Tell us