Water hardness in Châtillon (Hauts-de-Seine)
24.1 °fH very hard
Tap water in Châtillon (Hauts-de-Seine) is very hard: 24.1 °fH (241 mg/L · 14.1 gpg · 13.5 °dH).
Source: Ministère de la Santé (ARS), contrôle sanitaire SISE-Eaux, commune 92020 (2026-08) · data checked 2026-10-19
The SEDIF network, which serves Châtillon, mainly treats water from the Seine, the Marne and the Oise at the Choisy-le-Roi, Neuilly-sur-Marne and Méry-sur-Oise plants. These rivers cross the limestone terrain of the Paris Basin, hence 241.0 mg/L CaCO₃: hard water, with frequent deposits.
TH en °fH : douce < 15, moyennement dure 15–25, dure 25–35, très dure > 35 °fH (classes usuelles ARS).
Water data
| Total hardness | 24.1 °fH |
|---|---|
| Utility | Veolia Franciliane |
How Châtillon (Hauts-de-Seine) compares
- Tap water in Châtillon (Hauts-de-Seine) is close to the median of the 33641 cities we track in France (23.9 °fH).
- By hardness it ranks 16514 of 33641 in France (1 = hardest); 50 % of these cities have softer water.
- In Hauts-de-Seine it is number 3 of 36 cities; the regional median is 24.1 °fH.
- Nearest city with clearly softer water: Saint-Cloud, 7 km away (18.4 °fH).
- Nearest city with clearly harder water: Le Blanc-Mesnil, 20 km away (36.7 °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 Châtillon
| Brand | Setting for this water |
|---|---|
| Bosch | H04 |
| Miele | 14 °dH |
| AEG / Electrolux | 3 |
| Beko | 4th |
| 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 Châtillon (Hauts-de-Seine) water hard or soft?
It is very hard: 241 mg/L as CaCO₃ (14.1 gpg, 13.5 °dH). The usual bands are soft < 60, moderately hard 60–120, hard 120–180 and very hard > 180 mg/L.
Is tap water in Châtillon (Hauts-de-Seine) 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 Châtillon (Hauts-de-Seine) water?
14.1 gpg, equal to 13.5 °dH, 24.1 °fH or 241 mg/L calcium carbonate.
What dishwasher salt setting should I use in Châtillon (Hauts-de-Seine)?
For 241 mg/L (13.5 °dH) check your manufacturer's table: maximum level (5–7).
Do I need a water softener in Châtillon (Hauts-de-Seine)?
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 92020 (2026-08). Method: own measurement. Ministère de la Santé (ARS), contrôle sanitaire SISE-Eaux, commune 92020 · Outdated figure? Tell us