Water hardness in Rüsselsheim am Main
22.4 °dH very hard
Tap water in Rüsselsheim am Main is very hard: 22.4 °dH (400 mg/L · 23.4 gpg · 40 °fH).
Source: Stadtwerke Rüsselsheim, Wasserqualität page, values for 2025 (Stadtwerke Mainz area) (2025) · data checked 2026-10-20
Range across supply zones: 348–452 mg/L.
2 supply zones — hardness varies by neighbourhood; the figure above is the median.
Hardness by district / supply zone
| °dH | mg/L | ||
|---|---|---|---|
| Hessenwasser supply area | 19.5 | 348 | very hard |
| Stadtwerke Mainz supply area | 25.3 | 452 | very hard |
Rüsselsheim has two supply areas, one served from the Stadtwerke Mainz network and one from Hessenwasser, and the utility lists each separately for 2025. Hardness ranges from 348.1 to 451.6 mg/L CaCO₃, with a median of 399.8 mg/L, which places both areas well into the very hard class. Check which area your district belongs to, since the gap between them is large.
German law (WRMG) uses 3 bands: soft < 8.4 °dH, medium 8.4–14 °dH, hard > 14 °dH.
Water data
| Total hardness | 22.4 °dH |
|---|---|
| Utility | Wasserversorgung Rüsselsheim GmbH (Stadtwerke Rüsselsheim) |
How Rüsselsheim am Main compares
- Tap water in Rüsselsheim am Main is 95 % harder than the median of the 809 cities we track in Germany (11.5 °dH).
- By hardness it ranks 30 of 809 in Germany (1 = hardest); 96 % of these cities have softer water.
- In Hessen it is number 2 of 73 cities; the regional median is 10.7 °dH.
- Nearest city with clearly softer water: Mörfelden-Walldorf, 12 km away (12.9 °dH).
- Nearest city with clearly harder water: Nußloch, 79 km away (31.6 °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 Rüsselsheim am Main
| Brand | Setting for this water |
|---|---|
| Bosch | H06 |
| Miele | 22 °dH |
| AEG / Electrolux | 5 |
| Beko | 6th |
| Hoover | S3 |
| LG | H4 |
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 Rüsselsheim am Main water hard or soft?
It is very hard: 400 mg/L as CaCO₃ (23.4 gpg, 22.4 °dH). The usual bands are soft < 60, moderately hard 60–120, hard 120–180 and very hard > 180 mg/L.
Is tap water in Rüsselsheim am Main 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 Rüsselsheim am Main water?
23.4 gpg, equal to 22.4 °dH, 40 °fH or 400 mg/L calcium carbonate.
What dishwasher salt setting should I use in Rüsselsheim am Main?
For 400 mg/L (22.4 °dH) check your manufacturer's table: maximum level (5–7).
Do I need a water softener in Rüsselsheim am Main?
Yes, unless you are only passing through: scale damages appliances within a few years.
Source
Source: Stadtwerke Rüsselsheim, Wasserqualität page, values for 2025 (Stadtwerke Mainz area) (2025). Method: figure published by the water supplier. Stadtwerke Rüsselsheim, Wasserqualität page, values for 2025 (Stadtwerke Mainz area) · Outdated figure? Tell us