Water hardness in Solothurn
25.5 °fH very hard
Tap water in Solothurn is very hard: 25.5 °fH (255 mg/L · 14.9 gpg · 14.3 °dH).
Source: Regio Energie Solothurn (via SVGW trinkwasser.ch) (2025) · data checked 2026-10-21
In this region at the southern foot of the Jura, the water comes from groundwater and springs in Jura limestone, which explains the high hardness. Regio Energie Solothurn reports a hardness of 255.0 mg/L CaCO₃. Scale forms quickly on heating elements and fittings, so a softener or strict descaling routine is worth considering.
In der Schweiz wird meist in °fH angegeben (1 °fH = 0,56 °dH).
Water data
| Total hardness | 25.5 °fH |
|---|---|
| Utility | Regio Energie Solothurn |
How Solothurn compares
- Tap water in Solothurn is 5 % softer than the median of the 650 cities we track in Switzerland (26.7 °fH).
- By hardness it ranks 368 of 650 in Switzerland (1 = hardest); 43 % of these cities have softer water.
- In SO it is number 23 of 33 cities; the regional median is 25.7 °fH.
- Nearest city with clearly softer water: Welschenrohr-Gänsbrunnen, 8 km away (19.5 °fH).
- Nearest city with clearly harder water: Lüsslingen-Nennigkofen, 3 km away (32.9 °fH).
Ranking of the hardest and softest water in Switzerland →
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 Solothurn
| 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 Solothurn water hard or soft?
It is very hard: 255 mg/L as CaCO₃ (14.9 gpg, 14.3 °dH). The usual bands are soft < 60, moderately hard 60–120, hard 120–180 and very hard > 180 mg/L.
Is tap water in Solothurn safe to drink?
Hardness is not a health issue; it is about limescale, taste and appliances. Mains water must meet national drinking-water standards. In der Schweiz wird meist in °fH angegeben (1 °fH = 0,56 °dH).
How many grains per gallon is Solothurn water?
14.9 gpg, equal to 14.3 °dH, 25.5 °fH or 255 mg/L calcium carbonate.
What dishwasher salt setting should I use in Solothurn?
For 255 mg/L (14.3 °dH) check your manufacturer's table: maximum level (5–7).
Do I need a water softener in Solothurn?
Yes, unless you are only passing through: scale damages appliances within a few years.
Source
Source: Regio Energie Solothurn (via SVGW trinkwasser.ch) (2025). Method: figure published by the water supplier. Regio Energie Solothurn (via SVGW trinkwasser.ch) · Outdated figure? Tell us