Water hardness in Ulm
13.4 °dH very hard
Tap water in Ulm is very hard: 13.4 °dH (239 mg/L · 14 gpg · 23.9 °fH).
Source: SWU Netze - Analysedaten Trinkwasser Jahresmittelwerte 2025 (Stand 12.05.2026) (2025) · data checked 2026-10-19
Range across supply zones: 239–248 mg/L.
3 supply zones — hardness varies by neighbourhood; the figure above is the median.
Hardness by district / supply zone
| °dH | mg/L | ||
|---|---|---|---|
| Lehr (Ulm district; supplied by Wasserzweckverband Ulmer Alb) | 13.4 | 239 | very hard |
| Stadtgebiet Ulm (incl. Eselsberg, Soeflingen, Wiblingen, Grimmelfingen and others) | 13.9 | 248 | very hard |
| Zone Michelsberg (Ulm; mixed Landeswasserversorgung water) | 13.4 | 239 | very hard |
Ulm's utility SWU publishes 2025 annual means for the city area and for the Michelsberg zone, which gets mixed water from the Landeswasserversorgung. The district of Lehr is supplied separately by Wasserzweckverband Ulmer Alb. The median is 239.2 mg/L CaCO₃ and the range is 239.2 to 248.1 mg/L, with the main city area at the upper end. Neu-Ulm across the river is a separate supply and is not included.
German law (WRMG) uses 3 bands: soft < 8.4 °dH, medium 8.4–14 °dH, hard > 14 °dH.
Water data
| Total hardness | 13.4 °dH |
|---|
How Ulm compares
- Tap water in Ulm is 17 % harder than the median of the 809 cities we track in Germany (11.5 °dH).
- By hardness it ranks 322 of 809 in Germany (1 = hardest); 60 % of these cities have softer water.
- In Baden-Württemberg it is number 68 of 146 cities; the regional median is 12.8 °dH.
- Nearest city with clearly softer water: Neuffen, 48 km away (7.6 °dH).
- Nearest city with clearly harder water: Nersingen, 6 km away (18.1 °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 Ulm
| Brand | Setting for this water |
|---|---|
| Bosch | H04 |
| Miele | 13 °dH |
| AEG / Electrolux | 3 |
| Beko | 4th |
| Hoover | S2 |
| 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 Ulm water hard or soft?
It is very hard: 239 mg/L as CaCO₃ (14 gpg, 13.4 °dH). The usual bands are soft < 60, moderately hard 60–120, hard 120–180 and very hard > 180 mg/L.
Is tap water in Ulm 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 Ulm water?
14 gpg, equal to 13.4 °dH, 23.9 °fH or 239 mg/L calcium carbonate.
What dishwasher salt setting should I use in Ulm?
For 239 mg/L (13.4 °dH) check your manufacturer's table: maximum level (5–7).
Do I need a water softener in Ulm?
Yes, unless you are only passing through: scale damages appliances within a few years.
Source
Source: SWU Netze - Analysedaten Trinkwasser Jahresmittelwerte 2025 (Stand 12.05.2026) (2025). Method: figure published by the water supplier. SWU Netze - Analysedaten Trinkwasser Jahresmittelwerte 2025 (Stand 12.05.2026) · Outdated figure? Tell us