Water hardness in Sion
25.2 °fH very hard
Tap water in Sion is very hard: 25.2 °fH (252 mg/L · 14.7 gpg · 14.1 °dH).
Source: OIKEN SA (via SVGW trinkwasser.ch) (2024) · data checked 2026-10-21
Range across supply zones: 216–293 mg/L.
In Valais, drinking water comes from springs and groundwater, and the hardness depends strongly on the rock in the catchment. OIKEN SA reports a hardness of 252.0 mg/L CaCO₃, with values from 216.0 to 293.0 mg/L depending on the address. 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 | 25.2 °fH |
|---|---|
| Utility | OIKEN SA |
How Sion compares
- Tap water in Sion is 6 % softer than the median of the 650 cities we track in Switzerland (26.7 °fH).
- By hardness it ranks 374 of 650 in Switzerland (1 = hardest); 42 % of these cities have softer water.
- In VS it is number 1 of 17 cities; the regional median is 13.7 °fH.
- Nearest city with clearly softer water: Conthey, 4 km away (16.7 °fH).
- Nearest city with clearly harder water: Yvorne, 33 km away (32.6 °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 Sion
| 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 Sion water hard or soft?
It is very hard: 252 mg/L as CaCO₃ (14.7 gpg, 14.1 °dH). The usual bands are soft < 60, moderately hard 60–120, hard 120–180 and very hard > 180 mg/L.
Is tap water in Sion 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 Sion water?
14.7 gpg, equal to 14.1 °dH, 25.2 °fH or 252 mg/L calcium carbonate.
What dishwasher salt setting should I use in Sion?
For 252 mg/L (14.1 °dH) check your manufacturer's table: maximum level (5–7).
Do I need a water softener in Sion?
Yes, unless you are only passing through: scale damages appliances within a few years.
Source
Source: OIKEN SA (via SVGW trinkwasser.ch) (2024). Method: figure published by the water supplier. OIKEN SA (via SVGW trinkwasser.ch) · Outdated figure? Tell us