Water hardness in Helperknapp
21.3 °fH very hard
Tap water in Helperknapp is very hard: 21.3 °fH (213 mg/L · 12.4 gpg · 11.9 °dH).
Source: Administration de la gestion de l'eau (AGE), Dureté de l'eau (data.public.lu, CC0) (2022) · data checked 2026-10-20
This figure is over 3 years old; hardness may have changed.
Luxembourg communes report hardness in °fH (and °dH).
Water data
| Total hardness | 21.3 °fH |
|---|---|
| Utility | Commune de Helperknapp |
How Helperknapp compares
- Tap water in Helperknapp is 17 % harder than the median of the 101 cities we track in Luxembourg (18.2 °fH).
- By hardness it ranks 39 of 101 in Luxembourg (1 = hardest); 62 % of these cities have softer water.
- In Mersch it is number 9 of 10 cities; the regional median is 23.7 °fH.
- Nearest city with clearly softer water: Préizerdaul, 6 km away (9.3 °fH).
- Nearest city with clearly harder water: Colmar-Berg, 7 km away (30.5 °fH).
Ranking of the hardest and softest water in Luxembourg →
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 Helperknapp
| 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 Helperknapp water hard or soft?
It is very hard: 213 mg/L as CaCO₃ (12.4 gpg, 11.9 °dH). The usual bands are soft < 60, moderately hard 60–120, hard 120–180 and very hard > 180 mg/L.
Is tap water in Helperknapp safe to drink?
Hardness is not a health issue; it is about limescale, taste and appliances. Mains water must meet national drinking-water standards. Luxembourg communes report hardness in °fH (and °dH).
How many grains per gallon is Helperknapp water?
12.4 gpg, equal to 11.9 °dH, 21.3 °fH or 213 mg/L calcium carbonate.
What dishwasher salt setting should I use in Helperknapp?
For 213 mg/L (11.9 °dH) check your manufacturer's table: maximum level (5–7).
Do I need a water softener in Helperknapp?
Yes, unless you are only passing through: scale damages appliances within a few years.
Source
Source: Administration de la gestion de l'eau (AGE), Dureté de l'eau (data.public.lu, CC0) (2022). Method: figure published by the water supplier. Administration de la gestion de l'eau (AGE), Dureté de l'eau (data.public.lu, CC0) · Outdated figure? Tell us