Water hardness in Oissel-sur-Seine
30.6 °fH very hard
Tap water in Oissel-sur-Seine is very hard: 30.6 °fH (306 mg/L · 17.9 gpg · 17.1 °dH).
Source: Ministère de la Santé (ARS), contrôle sanitaire SISE-Eaux, commune 76484 (2026-08) · data checked 2026-10-19
Oissel-sur-Seine (Seine-Maritime) is supplied by Metropole Rouen Normandie. Health-ministry sanitary control data (ARS, SISE-Eaux, commune 76484, August 2026) give a measured hardness of 306 mg/L CaCO₃, or 30.6 °fH. That falls in the very hard band.
TH en °fH : douce < 15, moyennement dure 15–25, dure 25–35, très dure > 35 °fH (classes usuelles ARS).
Water data
| Total hardness | 30.6 °fH |
|---|---|
| Utility | Metropole Rouen Normandie |
How Oissel-sur-Seine compares
- Tap water in Oissel-sur-Seine is 28 % harder than the median of the 33641 cities we track in France (23.9 °fH).
- By hardness it ranks 7585 of 33641 in France (1 = hardest); 77 % of these cities have softer water.
- In Seine-Maritime it is number 76 of 682 cities; the regional median is 28.5 °fH.
- Nearest city with clearly softer water: Le Manoir, 9 km away (22.5 °fH).
- Nearest city with clearly harder water: Chérence, 51 km away (39.6 °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 Oissel-sur-Seine
| Brand | Setting for this water |
|---|---|
| Bosch | H05 |
| Miele | 17 °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 Oissel-sur-Seine water hard or soft?
It is very hard: 306 mg/L as CaCO₃ (17.9 gpg, 17.1 °dH). The usual bands are soft < 60, moderately hard 60–120, hard 120–180 and very hard > 180 mg/L.
Is tap water in Oissel-sur-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 Oissel-sur-Seine water?
17.9 gpg, equal to 17.1 °dH, 30.6 °fH or 306 mg/L calcium carbonate.
What dishwasher salt setting should I use in Oissel-sur-Seine?
For 306 mg/L (17.1 °dH) check your manufacturer's table: maximum level (5–7).
Do I need a water softener in Oissel-sur-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 76484 (2026-08). Method: own measurement. Ministère de la Santé (ARS), contrôle sanitaire SISE-Eaux, commune 76484 · Outdated figure? Tell us