Water hardness in Illnau-Effretikon
33.5 °fH very hard
Tap water in Illnau-Effretikon is very hard: 33.5 °fH (335 mg/L · 19.6 gpg · 18.8 °dH).
Source: Wasserversorgung Illnau-Effretikon (via SVGW trinkwasser.ch) (2025) · data checked 2026-10-21
In the canton of Zurich, drinking water comes partly from Lake Zurich and partly from groundwater and springs, and communities relying mostly on groundwater and springs tend to have harder water. Wasserversorgung Illnau-Effretikon reports a hardness of 335.0 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 | 33.5 °fH |
|---|---|
| Utility | Wasserversorgung Illnau-Effretikon |
How Illnau-Effretikon compares
- Tap water in Illnau-Effretikon is 25 % harder than the median of the 650 cities we track in Switzerland (26.7 °fH).
- By hardness it ranks 131 of 650 in Switzerland (1 = hardest); 80 % of these cities have softer water.
- In ZH it is number 28 of 116 cities; the regional median is 28.4 °fH.
- Nearest city with clearly softer water: Wila, 9 km away (25.9 °fH).
- Nearest city with clearly harder water: Rorbas, 17 km away (44.1 °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 Illnau-Effretikon
| Brand | Setting for this water |
|---|---|
| Bosch | H05 |
| Miele | 19 °dH |
| AEG / Electrolux | 5 |
| 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 Illnau-Effretikon water hard or soft?
It is very hard: 335 mg/L as CaCO₃ (19.6 gpg, 18.8 °dH). The usual bands are soft < 60, moderately hard 60–120, hard 120–180 and very hard > 180 mg/L.
Is tap water in Illnau-Effretikon 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 Illnau-Effretikon water?
19.6 gpg, equal to 18.8 °dH, 33.5 °fH or 335 mg/L calcium carbonate.
What dishwasher salt setting should I use in Illnau-Effretikon?
For 335 mg/L (18.8 °dH) check your manufacturer's table: maximum level (5–7).
Do I need a water softener in Illnau-Effretikon?
Yes, unless you are only passing through: scale damages appliances within a few years.
Source
Source: Wasserversorgung Illnau-Effretikon (via SVGW trinkwasser.ch) (2025). Method: figure published by the water supplier. Wasserversorgung Illnau-Effretikon (via SVGW trinkwasser.ch) · Outdated figure? Tell us