Water hardness in Jena
16 °dH very hard
Tap water in Jena is very hard: 16 °dH (286 mg/L · 16.7 gpg · 28.6 °fH).
Source: Zweckverband JenaWasser, Trinkwasserbeschaffenheit 2025 (2025-12) · data checked 2026-10-22
Range across supply zones: 57–539 mg/L.
9 supply zones — hardness varies by neighbourhood; the figure above is the median.
Hardness by district / supply zone
| °dH | mg/L | ||
|---|---|---|---|
| Thüringer Fernwasserversorgung (Wasserwerk Luisenthal) | 3.2 | 57 | soft |
| Wasserwerk Burgau | 18.6 | 332 | very hard |
| Wasserwerk Drackendorf | 15.2 | 271 | very hard |
| Wasserwerk Jenalöbnitz | 16.6 | 296 | very hard |
| Wasserwerk Porstendorf (new build in operation since 19.03.2025) | 16.5 | 295 | very hard |
| Wasserwerk Steudnitz | 30.2 | 539 | very hard |
| Zweckverband Eisenberg (Wasserwerk Ullrichsberg) | 15.8 | 282 | very hard |
| Zweckverband Holzland (Tiefbrunnen Kleinpürschitz) | 13.6 | 243 | very hard |
| Zweckverband Holzland (Tiefbrunnen Zeitzgrund) | 16 | 286 | very hard |
JenaWasser blends water from several waterworks and external suppliers, and its December 2025 table lists eight of them. The median is 283.8 mg/L CaCO₃, but the range runs from 57.1 to 332.0 mg/L. The soft end is water bought from the Thüringer Fernwasserversorgung. Which supply reaches your tap depends on the street, so check the supply-system table before choosing a softener.
German law (WRMG) uses 3 bands: soft < 8.4 °dH, medium 8.4–14 °dH, hard > 14 °dH.
Water data
| Total hardness | 16 °dH |
|---|---|
| Utility | Zweckverband JenaWasser |
How Jena compares
- Tap water in Jena is 39 % harder than the median of the 809 cities we track in Germany (11.5 °dH).
- By hardness it ranks 223 of 809 in Germany (1 = hardest); 72 % of these cities have softer water.
- In Thüringen it is number 5 of 8 cities; the regional median is 16.5 °dH.
- Nearest city with clearly softer water: Pausa, 48 km away (8.2 °dH).
- Nearest city with clearly harder water: Bad Kösen, 25 km away (21 °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 Jena
| Brand | Setting for this water |
|---|---|
| Bosch | H04 |
| Miele | 16 °dH |
| AEG / Electrolux | 4 |
| Beko | 5th |
| 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 Jena water hard or soft?
It is very hard: 286 mg/L as CaCO₃ (16.7 gpg, 16 °dH). The usual bands are soft < 60, moderately hard 60–120, hard 120–180 and very hard > 180 mg/L.
Is tap water in Jena 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 Jena water?
16.7 gpg, equal to 16 °dH, 28.6 °fH or 286 mg/L calcium carbonate.
What dishwasher salt setting should I use in Jena?
For 286 mg/L (16 °dH) check your manufacturer's table: maximum level (5–7).
Do I need a water softener in Jena?
Yes, unless you are only passing through: scale damages appliances within a few years.
Source
Source: Zweckverband JenaWasser, Trinkwasserbeschaffenheit 2025 (2025-12). Method: figure published by the water supplier. Zweckverband JenaWasser, Trinkwasserbeschaffenheit 2025 · Outdated figure? Tell us