Water hardness in Maisons-Laffitte
9.8 °fH moderately hard
Tap water in Maisons-Laffitte is moderately hard: 9.8 °fH (98 mg/L · 5.7 gpg · 5.5 °dH).
Source: Ministère de la Santé (ARS), contrôle sanitaire SISE-Eaux, commune 78358 (2026-08) · data checked 2026-10-19
In Maisons-Laffitte the water is supplied by the Compagnie des Eaux de Maisons-Laffitte. The ARS health monitoring (SISE-Eaux, August 2026) gives 98 mg/L CaCO₃, or 9.8 °f: moderately hard water, based on measurements. Limescale is present but less pronounced than with very hard water.
TH en °fH : douce < 15, moyennement dure 15–25, dure 25–35, très dure > 35 °fH (classes usuelles ARS).
Water data
| Total hardness | 9.8 °fH |
|---|---|
| Utility | Cie Eaux Maisons-Laffitte |
How Maisons-Laffitte compares
- Tap water in Maisons-Laffitte is 59 % softer than the median of the 33641 cities we track in France (23.9 °fH).
- By hardness it ranks 28991 of 33641 in France (1 = hardest); 13 % of these cities have softer water.
- In Yvelines it is number 222 of 222 cities; the regional median is 23 °fH.
- Nearest city with clearly softer water: Friaize, 94 km away (6.2 °fH).
- Nearest city with clearly harder water: Le Mesnil-le-Roi, 2 km away (22 °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 Maisons-Laffitte
| Brand | Setting for this water |
|---|---|
| Bosch | H00 |
| Miele | 5 °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 Maisons-Laffitte water hard or soft?
It is moderately hard: 98 mg/L as CaCO₃ (5.7 gpg, 5.5 °dH). The usual bands are soft < 60, moderately hard 60–120, hard 120–180 and very hard > 180 mg/L.
Is tap water in Maisons-Laffitte 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 Maisons-Laffitte water?
5.7 gpg, equal to 5.5 °dH, 9.8 °fH or 98 mg/L calcium carbonate.
What dishwasher salt setting should I use in Maisons-Laffitte?
For 98 mg/L (5.5 °dH) check your manufacturer's table: level 2–3.
Do I need a water softener in Maisons-Laffitte?
Not essential; a scale inhibitor protects the heater cheaply.
Source
Source: Ministère de la Santé (ARS), contrôle sanitaire SISE-Eaux, commune 78358 (2026-08). Method: own measurement. Ministère de la Santé (ARS), contrôle sanitaire SISE-Eaux, commune 78358 · Outdated figure? Tell us