Water hardness in Gex
18.6 °fH very hard
Tap water in Gex is very hard: 18.6 °fH (186 mg/L · 10.9 gpg · 10.4 °dH).
Source: Ministère de la Santé (ARS), contrôle sanitaire SISE-Eaux, commune 01173 (2026-08) · data checked 2026-10-19
Range across supply zones: 135–247 mg/L.
Gex (Ain) is served by the Régie Des Eaux Gessiennes. The median is 186 mg/L CaCO₃, with August 2026 measurements from 135 to 247 mg/L. The gap is clear: hardness varies from one sample to another.
TH en °fH : douce < 15, moyennement dure 15–25, dure 25–35, très dure > 35 °fH (classes usuelles ARS).
Water data
| Total hardness | 18.6 °fH |
|---|---|
| Utility | Regie Des Eaux Gessiennes |
How Gex compares
- Tap water in Gex is 22 % softer than the median of the 33641 cities we track in France (23.9 °fH).
- By hardness it ranks 21293 of 33641 in France (1 = hardest); 36 % of these cities have softer water.
- In Ain it is number 348 of 373 cities; the regional median is 25.2 °fH.
- Nearest city with clearly softer water: Vesancy, 3 km away (4 °fH).
- Nearest city with clearly harder water: Échenevex, 3 km away (24.6 °fH).
Ranking of the hardest and softest water in France →
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 Gex
| Brand | Setting for this water |
|---|---|
| Bosch | H03 |
| Miele | 10 °dH |
| AEG / Electrolux | 2 |
| Beko | 3rd |
| Hoover | S2 |
| 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 Gex water hard or soft?
It is very hard: 186 mg/L as CaCO₃ (10.9 gpg, 10.4 °dH). The usual bands are soft < 60, moderately hard 60–120, hard 120–180 and very hard > 180 mg/L.
Is tap water in Gex safe to drink?
Hardness is not a health issue; it is about limescale, taste and appliances. Mains water must meet national drinking-water standards. TH en °fH : douce < 15, moyennement dure 15–25, dure 25–35, très dure > 35 °fH (classes usuelles ARS).
How many grains per gallon is Gex water?
10.9 gpg, equal to 10.4 °dH, 18.6 °fH or 186 mg/L calcium carbonate.
What dishwasher salt setting should I use in Gex?
For 186 mg/L (10.4 °dH) check your manufacturer's table: maximum level (5–7).
Do I need a water softener in Gex?
Yes, unless you are only passing through: scale damages appliances within a few years.
Source
Source: Ministère de la Santé (ARS), contrôle sanitaire SISE-Eaux, commune 01173 (2026-08). Method: own measurement. Ministère de la Santé (ARS), contrôle sanitaire SISE-Eaux, commune 01173 · Outdated figure? Tell us