Water hardness in Bad Honnef
14.4 °dH very hard
Tap water in Bad Honnef is very hard: 14.4 °dH (257 mg/L · 15 gpg · 25.7 °fH).
Source: Bad Honnef AG – Trinkwasseranalyse 2026 (2026-05) · data checked 2026-11-02
Bad Honnef AG's 2026 analysis, which also covers Aegidienberg, gives 257.2 mg/L CaCO₃, with calcium at 78.8 mg/L and magnesium at 14.8 mg/L. Königswinter, only a few kilometres away, reports 121.4 mg/L, so the water changes noticeably across short distances along the Rhine. The analysis does not state the water source in the data we hold, so check the utility's PDF for details.
German law (WRMG) uses 3 bands: soft < 8.4 °dH, medium 8.4–14 °dH, hard > 14 °dH.
Water data
| Total hardness | 14.4 °dH |
|---|---|
| Calcium (mg/L) | 78.8 |
| Magnesium (mg/L) | 14.8 |
| Utility | Bad Honnef AG |
How Bad Honnef compares
- Tap water in Bad Honnef is 25 % harder than the median of the 809 cities we track in Germany (11.5 °dH).
- By hardness it ranks 278 of 809 in Germany (1 = hardest); 66 % of these cities have softer water.
- In Nordrhein-Westfalen it is number 33 of 153 cities; the regional median is 11.3 °dH.
- Nearest city with clearly softer water: Königswinter, 4 km away (6.8 °dH).
- Nearest city with clearly harder water: Pulheim, 48 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 Bad Honnef
| Brand | Setting for this water |
|---|---|
| Bosch | H04 |
| Miele | 14 °dH |
| AEG / Electrolux | 3 |
| Beko | 4th |
| 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 Bad Honnef water hard or soft?
It is very hard: 257 mg/L as CaCO₃ (15 gpg, 14.4 °dH). The usual bands are soft < 60, moderately hard 60–120, hard 120–180 and very hard > 180 mg/L.
Is tap water in Bad Honnef 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 Bad Honnef water?
15 gpg, equal to 14.4 °dH, 25.7 °fH or 257 mg/L calcium carbonate.
What dishwasher salt setting should I use in Bad Honnef?
For 257 mg/L (14.4 °dH) check your manufacturer's table: maximum level (5–7).
Do I need a water softener in Bad Honnef?
Yes, unless you are only passing through: scale damages appliances within a few years.
Source
Source: Bad Honnef AG – Trinkwasseranalyse 2026 (2026-05). Method: figure published by the water supplier. Bad Honnef AG – Trinkwasseranalyse 2026 · Outdated figure? Tell us