Water hardness in Zurich
15.8 °fH hard
Tap water in Zurich is hard: 15.8 °fH (158 mg/L · 9.2 gpg · 8.9 °dH).
Source: Stadt Zürich, Die Qualität des Zürcher Trinkwassers 2025 (2025) · data checked 2026-10-20
Range across supply zones: 138–191 mg/L.
Wasserversorgung Zürich reports a mean total hardness of 158 mg/L CaCO₃ (15.8 °fH) in its 2025 water quality report. The three treatment plants differ: values run from 138 mg/L at Lengg to 191 mg/L at Moos, measured at plant outlet. The report does not say which districts get which plant's water, so check with the utility before sizing a softener.
In der Schweiz wird meist in °fH angegeben (1 °fH = 0,56 °dH).
Water data
| Total hardness | 15.8 °fH |
|---|---|
| Utility | Wasserversorgung Zürich (Departement der Industriellen Betriebe, Stadt Zürich) |
How Zurich compares
- Tap water in Zurich is 41 % softer than the median of the 650 cities we track in Switzerland (26.7 °fH).
- By hardness it ranks 566 of 650 in Switzerland (1 = hardest); 13 % of these cities have softer water.
- In ZH it is number 112 of 116 cities; the regional median is 28.4 °fH.
- Nearest city with clearly softer water: Merenschwand, 18 km away (11.6 °fH).
- Nearest city with clearly harder water: Kilchberg, 6 km away (27.3 °fH).
Ranking of the hardest and softest water in Switzerland →
What it means at home
- Fast scale on taps, shower screens and kettle; white spots on glassware.
- Water heater: efficiency loss and element failures within years if unprotected.
- Dry skin and dull hair after showering are common.
- Softener recommended; jug or reverse osmosis for drinking.
How much salt will you use for softening?
Recommended, especially with a heater or boiler: scale cuts efficiency and shortens its life.
Descale a coffee machine or kettle about every 2 months (typical manufacturer guidance for this hardness).
Estimates for planning, not a quote. Check your appliance manual for exact settings.
Dishwasher setting in Zurich
| Brand | Setting for this water |
|---|---|
| Bosch | H02 |
| Miele | 9 °dH |
| AEG / Electrolux | 2 |
| Beko | 3rd |
| Hoover | S1 |
| 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 Zurich water hard or soft?
It is hard: 158 mg/L as CaCO₃ (9.2 gpg, 8.9 °dH). The usual bands are soft < 60, moderately hard 60–120, hard 120–180 and very hard > 180 mg/L.
Is tap water in Zurich 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 Zurich water?
9.2 gpg, equal to 8.9 °dH, 15.8 °fH or 158 mg/L calcium carbonate.
What dishwasher salt setting should I use in Zurich?
For 158 mg/L (8.9 °dH) check your manufacturer's table: level 4–5.
Do I need a water softener in Zurich?
Recommended if you have a water heater, boiler or tankless unit: it saves repairs and detergent.
Source
Source: Stadt Zürich, Die Qualität des Zürcher Trinkwassers 2025 (2025). Method: figure published by the water supplier. Stadt Zürich, Die Qualität des Zürcher Trinkwassers 2025 · Outdated figure? Tell us