Water hardness in Olten
31 °fH very hard
Tap water in Olten is very hard: 31 °fH (310 mg/L · 18.1 gpg · 17.4 °dH).
Source: Städtische Betriebe Olten (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. Städtische Betriebe Olten reports a hardness of 310.0 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 | 31 °fH |
|---|---|
| Utility | Städtische Betriebe Olten |
How Olten compares
- Tap water in Olten is 16 % harder than the median of the 650 cities we track in Switzerland (26.7 °fH).
- By hardness it ranks 208 of 650 in Switzerland (1 = hardest); 68 % of these cities have softer water.
- In SO it is number 7 of 33 cities; the regional median is 25.7 °fH.
- Nearest city with clearly softer water: Vordemwald, 8 km away (14.9 °fH).
- Nearest city with clearly harder water: Läufelfingen, 6 km away (39 °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 Olten
| Brand | Setting for this water |
|---|---|
| Bosch | H05 |
| Miele | 17 °dH |
| AEG / Electrolux | 4 |
| Beko | 5th |
| Hoover | S3 |
| 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 Olten water hard or soft?
It is very hard: 310 mg/L as CaCO₃ (18.1 gpg, 17.4 °dH). The usual bands are soft < 60, moderately hard 60–120, hard 120–180 and very hard > 180 mg/L.
Is tap water in Olten 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 Olten water?
18.1 gpg, equal to 17.4 °dH, 31 °fH or 310 mg/L calcium carbonate.
What dishwasher salt setting should I use in Olten?
For 310 mg/L (17.4 °dH) check your manufacturer's table: maximum level (5–7).
Do I need a water softener in Olten?
Yes, unless you are only passing through: scale damages appliances within a few years.
Source
Source: Städtische Betriebe Olten (via SVGW trinkwasser.ch) (2025). Method: figure published by the water supplier. Städtische Betriebe Olten (via SVGW trinkwasser.ch) · Outdated figure? Tell us