Water hardness in Offenbach am Main
11.7 °dH very hard
Tap water in Offenbach am Main is very hard: 11.7 °dH (209 mg/L · 12.2 gpg · 20.9 °fH).
Source: ZWO, Trinkwasseranalyse 2. Quartal 2026, Versorgungsgebiet 7 (2026-07) · data checked 2026-10-19
Range across supply zones: 187–230 mg/L.
ZWO, the water association for the city and district of Offenbach, publishes a second-quarter 2026 analysis for supply area 7, which excludes the harbour, Kaiserlei and the northern Nordend. The value of 208.8 mg/L CaCO₃ is computed from a quarterly range of 187.4 to 230.3 mg/L. The sheet contains a second hardness row that disagrees with this range, and we followed the one that matches the printed calcium and magnesium. Excluded districts are not covered.
German law (WRMG) uses 3 bands: soft < 8.4 °dH, medium 8.4–14 °dH, hard > 14 °dH.
Water data
| Total hardness | 11.7 °dH |
|---|---|
| Utility | ZWO (Zweckverband Wasserversorgung Stadt und Kreis Offenbach) |
How Offenbach am Main compares
- Tap water in Offenbach am Main is close to the median of the 809 cities we track in Germany (11.5 °dH).
- By hardness it ranks 394 of 809 in Germany (1 = hardest); 51 % of these cities have softer water.
- In Hessen it is number 33 of 73 cities; the regional median is 10.7 °dH.
- Nearest city with clearly softer water: Großkrotzenburg, 15 km away (8.8 °dH).
- Nearest city with clearly harder water: Mühlheim am Main, 6 km away (17 °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 Offenbach am Main
| Brand | Setting for this water |
|---|---|
| Bosch | H03 |
| Miele | 12 °dH |
| AEG / Electrolux | 3 |
| Beko | 3rd |
| 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 Offenbach am Main water hard or soft?
It is very hard: 209 mg/L as CaCO₃ (12.2 gpg, 11.7 °dH). The usual bands are soft < 60, moderately hard 60–120, hard 120–180 and very hard > 180 mg/L.
Is tap water in Offenbach 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 Offenbach am Main water?
12.2 gpg, equal to 11.7 °dH, 20.9 °fH or 209 mg/L calcium carbonate.
What dishwasher salt setting should I use in Offenbach am Main?
For 209 mg/L (11.7 °dH) check your manufacturer's table: maximum level (5–7).
Do I need a water softener in Offenbach am Main?
Yes, unless you are only passing through: scale damages appliances within a few years.
Source
Source: ZWO, Trinkwasseranalyse 2. Quartal 2026, Versorgungsgebiet 7 (2026-07). Method: computed from supplier's calcium and magnesium. ZWO, Trinkwasseranalyse 2. Quartal 2026, Versorgungsgebiet 7 · Outdated figure? Tell us