Water hardness in Mülheim an der Ruhr
8.3 °dH hard
Tap water in Mülheim an der Ruhr is hard: 8.3 °dH (148 mg/L · 8.7 gpg · 14.8 °fH).
Source: RWW - Trinkwasserdaten 2025 (Median, Niedrigstwert, Hoechstwert) (2025) · data checked 2026-10-19
Range across supply zones: 102–191 mg/L.
2 supply zones — hardness varies by neighbourhood; the figure above is the median.
Hardness by district / supply zone
| °dH | mg/L | ||
|---|---|---|---|
| Muelheim (ohne Mintard); works Muelheim-Styrum-Ost and -West | 8 | 143 | hard |
| Muelheim-Mintard | 8.6 | 154 | hard |
RWW supplies Mülheim from the Styrum-Ost and Styrum-West works. The main table covers Mülheim without Mintard and is shared with parts of Oberhausen, Ratingen and Bottrop, while Mintard has its own 2025 table. The median is 148.2 mg/L CaCO₃ and the range is 101.7 to 191.0 mg/L. Mintard sits at the harder end.
German law (WRMG) uses 3 bands: soft < 8.4 °dH, medium 8.4–14 °dH, hard > 14 °dH.
Water data
| Total hardness | 8.3 °dH |
|---|
How Mülheim an der Ruhr compares
- Tap water in Mülheim an der Ruhr is 28 % softer than the median of the 809 cities we track in Germany (11.5 °dH).
- By hardness it ranks 559 of 809 in Germany (1 = hardest); 31 % of these cities have softer water.
- In Nordrhein-Westfalen it is number 107 of 153 cities; the regional median is 11.3 °dH.
- Nearest city with clearly softer water: Essen, 9 km away (6.6 °dH).
- Nearest city with clearly harder water: Oberhausen, 5 km away (10.8 °dH).
Ranking of the hardest and softest water in Germany →
What it means at home
- Fast scale on taps, shower screens and kettle; white spots on glassware.
- Water heater: efficiency loss and element failures within years if unprotected.
- Dry skin and dull hair after showering are common.
- Softener recommended; jug or reverse osmosis for drinking.
How much salt will you use for softening?
Recommended, especially with a heater or boiler: scale cuts efficiency and shortens its life.
Descale a coffee machine or kettle about every 2 months (typical manufacturer guidance for this hardness).
Estimates for planning, not a quote. Check your appliance manual for exact settings.
Dishwasher setting in Mülheim an der Ruhr
| Brand | Setting for this water |
|---|---|
| Bosch | H02 |
| Miele | 8 °dH |
| AEG / Electrolux | 2 |
| Beko | 3rd |
| Hoover | S1 |
| LG | H2 |
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 Mülheim an der Ruhr water hard or soft?
It is hard: 148 mg/L as CaCO₃ (8.7 gpg, 8.3 °dH). The usual bands are soft < 60, moderately hard 60–120, hard 120–180 and very hard > 180 mg/L.
Is tap water in Mülheim an der Ruhr 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 Mülheim an der Ruhr water?
8.7 gpg, equal to 8.3 °dH, 14.8 °fH or 148 mg/L calcium carbonate.
What dishwasher salt setting should I use in Mülheim an der Ruhr?
For 148 mg/L (8.3 °dH) check your manufacturer's table: level 4–5.
Do I need a water softener in Mülheim an der Ruhr?
Recommended if you have a water heater, boiler or tankless unit: it saves repairs and detergent.
Source
Source: RWW - Trinkwasserdaten 2025 (Median, Niedrigstwert, Hoechstwert) (2025). Method: figure published by the water supplier. RWW - Trinkwasserdaten 2025 (Median, Niedrigstwert, Hoechstwert) · Outdated figure? Tell us