Water hardness in Montpellier
32.9 °fH very hard
Tap water in Montpellier is very hard: 32.9 °fH (329 mg/L · 19.2 gpg · 18.4 °dH).
Source: Ministère de la Santé (ARS), contrôle sanitaire SISE-Eaux, commune 34172 (2026-08) · data checked 2026-10-19
Range across supply zones: 324–334 mg/L.
Montpellier's water comes largely from the Lez spring, a karst resurgence, and increasingly from the Rhône, treated at the Valédeau plant. The limestone karst north of the city loads the water with carbonates: 329.0 mg/L CaCO₃, between 324.0 and 334.0 mg/L. It is among the hardest water on the list, and scale affects every appliance.
TH en °fH : douce < 15, moyennement dure 15–25, dure 25–35, très dure > 35 °fH (classes usuelles ARS).
Water data
| Total hardness | 32.9 °fH |
|---|---|
| Utility | Regie Des Eaux Montpellier 3M |
How Montpellier compares
- Tap water in Montpellier is 38 % harder than the median of the 33641 cities we track in France (23.9 °fH).
- By hardness it ranks 4666 of 33641 in France (1 = hardest); 86 % of these cities have softer water.
- In Hérault it is number 67 of 324 cities; the regional median is 25.7 °fH.
- Nearest city with clearly softer water: Lattes, 5 km away (19.9 °fH).
- Nearest city with clearly harder water: Clapiers, 5 km away (49 °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 Montpellier
| Brand | Setting for this water |
|---|---|
| Bosch | H05 |
| Miele | 18 °dH |
| AEG / Electrolux | 4 |
| 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 Montpellier water hard or soft?
It is very hard: 329 mg/L as CaCO₃ (19.2 gpg, 18.4 °dH). The usual bands are soft < 60, moderately hard 60–120, hard 120–180 and very hard > 180 mg/L.
Is tap water in Montpellier 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 Montpellier water?
19.2 gpg, equal to 18.4 °dH, 32.9 °fH or 329 mg/L calcium carbonate.
What dishwasher salt setting should I use in Montpellier?
For 329 mg/L (18.4 °dH) check your manufacturer's table: maximum level (5–7).
Do I need a water softener in Montpellier?
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 34172 (2026-08). Method: own measurement. Ministère de la Santé (ARS), contrôle sanitaire SISE-Eaux, commune 34172 · Outdated figure? Tell us