Water hardness in Mont-de-Marsan
11.6 °fH moderately hard
Tap water in Mont-de-Marsan is moderately hard: 11.6 °fH (116 mg/L · 6.8 gpg · 6.5 °dH).
Source: Ministère de la Santé (ARS), contrôle sanitaire SISE-Eaux, commune 40192 (2026-08) · data checked 2026-10-19
In Mont-de-Marsan (Landes), measured hardness is 116 mg/L CaCO₃, or 11.6 °f. That is moderately hard water. The listed supplier is Mont de Eau Agglo. Source: ARS sanitary monitoring (SISE-Eaux), August 2026.
TH en °fH : douce < 15, moyennement dure 15–25, dure 25–35, très dure > 35 °fH (classes usuelles ARS).
Water data
| Total hardness | 11.6 °fH |
|---|---|
| Utility | Mont De Eau Agglo |
How Mont-de-Marsan compares
- Tap water in Mont-de-Marsan is 51 % softer than the median of the 33641 cities we track in France (23.9 °fH).
- By hardness it ranks 27454 of 33641 in France (1 = hardest); 18 % of these cities have softer water.
- In Landes it is number 218 of 288 cities; the regional median is 16.8 °fH.
- Nearest city with clearly softer water: Ousse-Suzan, 22 km away (8.3 °fH).
- Nearest city with clearly harder water: Mazerolles, 5 km away (26.2 °fH).
Ranking of the hardest and softest water in France →
What it means at home
- Visible kettle scale every few weeks; vinegar or citric acid is enough.
- Water heater and washing machine: some long-term scale; a scale inhibitor slows it.
- Dishwasher: medium salt setting.
- Softener optional; pays off mainly with a gas boiler or tankless heater.
How much salt will you use for softening?
Optional. A scale inhibitor or a small softener protects the heater; soap savings are modest.
Descale a coffee machine or kettle about every 3 months (typical manufacturer guidance for this hardness).
Estimates for planning, not a quote. Check your appliance manual for exact settings.
Dishwasher setting in Mont-de-Marsan
| Brand | Setting for this water |
|---|---|
| Bosch | H01 |
| Miele | 6 °dH |
| AEG / Electrolux | 2 |
| Beko | 2nd |
| Hoover | S1 |
| LG | H1 |
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 Mont-de-Marsan water hard or soft?
It is moderately hard: 116 mg/L as CaCO₃ (6.8 gpg, 6.5 °dH). The usual bands are soft < 60, moderately hard 60–120, hard 120–180 and very hard > 180 mg/L.
Is tap water in Mont-de-Marsan 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 Mont-de-Marsan water?
6.8 gpg, equal to 6.5 °dH, 11.6 °fH or 116 mg/L calcium carbonate.
What dishwasher salt setting should I use in Mont-de-Marsan?
For 116 mg/L (6.5 °dH) check your manufacturer's table: level 2–3.
Do I need a water softener in Mont-de-Marsan?
Not essential; a scale inhibitor protects the heater cheaply.
Source
Source: Ministère de la Santé (ARS), contrôle sanitaire SISE-Eaux, commune 40192 (2026-08). Method: own measurement. Ministère de la Santé (ARS), contrôle sanitaire SISE-Eaux, commune 40192 · Outdated figure? Tell us