Water hardness in Lagny-sur-Marne
27.4 °fH very hard
Tap water in Lagny-sur-Marne is very hard: 27.4 °fH (274 mg/L · 16 gpg · 15.4 °dH).
Source: Ministère de la Santé (ARS), contrôle sanitaire SISE-Eaux, commune 77243 (2026-08) · data checked 2026-10-19
Water in Lagny-sur-Marne (Seine-et-Marne) is supplied by Veolia Eau - Territoire Marne & Oise. The ARS health-control data (August 2026) show 274 mg/L CaCO₃. This is very hard water that leaves white deposits on dishes and taps.
TH en °fH : douce < 15, moyennement dure 15–25, dure 25–35, très dure > 35 °fH (classes usuelles ARS).
Water data
| Total hardness | 27.4 °fH |
|---|---|
| Utility | Veolia Eau - Territoire Marne & Oise |
How Lagny-sur-Marne compares
- Tap water in Lagny-sur-Marne is 15 % harder than the median of the 33641 cities we track in France (23.9 °fH).
- By hardness it ranks 12301 of 33641 in France (1 = hardest); 63 % of these cities have softer water.
- In Seine-et-Marne it is number 275 of 500 cities; the regional median is 27.7 °fH.
- Nearest city with clearly softer water: Villeneuve-sous-Dammartin, 18 km away (20.4 °fH).
- Nearest city with clearly harder water: Charmentray, 9 km away (54.9 °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 Lagny-sur-Marne
| Brand | Setting for this water |
|---|---|
| Bosch | H04 |
| Miele | 15 °dH |
| AEG / Electrolux | 4 |
| Beko | 4th |
| Hoover | S2 |
| 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 Lagny-sur-Marne water hard or soft?
It is very hard: 274 mg/L as CaCO₃ (16 gpg, 15.4 °dH). The usual bands are soft < 60, moderately hard 60–120, hard 120–180 and very hard > 180 mg/L.
Is tap water in Lagny-sur-Marne 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 Lagny-sur-Marne water?
16 gpg, equal to 15.4 °dH, 27.4 °fH or 274 mg/L calcium carbonate.
What dishwasher salt setting should I use in Lagny-sur-Marne?
For 274 mg/L (15.4 °dH) check your manufacturer's table: maximum level (5–7).
Do I need a water softener in Lagny-sur-Marne?
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 77243 (2026-08). Method: own measurement. Ministère de la Santé (ARS), contrôle sanitaire SISE-Eaux, commune 77243 · Outdated figure? Tell us