Water hardness in Rösrath
6.5 °dH moderately hard
Tap water in Rösrath is moderately hard: 6.5 °dH (117 mg/L · 6.8 gpg · 11.7 °fH).
Source: Stadtwerke Rösrath, Trinkwasseranalyse Ausgabe 2026 (Datengrundlage 2025) (2025) · data checked 2026-10-23
Stadtwerke Rösrath publishes one figure for its Leidenhausen waterworks, 6.55 °dH or 116.9 mg/L CaCO₃, based on 2025 data in the 2026 edition of its analysis. It is in the soft band under the WRMG. A single works supplies the town, so there are no zone differences to expect.
German law (WRMG) uses 3 bands: soft < 8.4 °dH, medium 8.4–14 °dH, hard > 14 °dH.
Water data
| Total hardness | 6.5 °dH |
|---|---|
| Utility | Stadtwerke Rösrath AöR |
How Rösrath compares
- Tap water in Rösrath is 43 % softer than the median of the 809 cities we track in Germany (11.5 °dH).
- By hardness it ranks 673 of 809 in Germany (1 = hardest); 17 % of these cities have softer water.
- In Nordrhein-Westfalen it is number 130 of 153 cities; the regional median is 11.3 °dH.
- Nearest city with clearly softer water: Lohmar, 7 km away (4.7 °dH).
- Nearest city with clearly harder water: Overath, 8 km away (9.7 °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 Rösrath
| Brand | Setting for this water |
|---|---|
| Bosch | H01 |
| Miele | 7 °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 Rösrath water hard or soft?
It is moderately hard: 117 mg/L as CaCO₃ (6.8 gpg, 6.5 °dH). The usual bands are soft < 60, moderately hard 60–120, hard 120–180 and very hard > 180 mg/L.
Is tap water in Rösrath 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 Rösrath water?
6.8 gpg, equal to 6.5 °dH, 11.7 °fH or 117 mg/L calcium carbonate.
What dishwasher salt setting should I use in Rösrath?
For 117 mg/L (6.5 °dH) check your manufacturer's table: level 2–3.
Do I need a water softener in Rösrath?
Not essential; a scale inhibitor protects the heater cheaply.
Source
Source: Stadtwerke Rösrath, Trinkwasseranalyse Ausgabe 2026 (Datengrundlage 2025) (2025). Method: figure published by the water supplier. Stadtwerke Rösrath, Trinkwasseranalyse Ausgabe 2026 (Datengrundlage 2025) · Outdated figure? Tell us