Water hardness in Saint-Étienne-du-Rouvray
30.8 °fH very hard
Tap water in Saint-Étienne-du-Rouvray is very hard: 30.8 °fH (308 mg/L · 18 gpg · 17.3 °dH).
Source: Ministère de la Santé (ARS), contrôle sanitaire SISE-Eaux, commune 76575 (2026-08) · data checked 2026-10-19
In Saint-Étienne-du-Rouvray (Seine-Maritime), water from Métropole Rouen Normandie shows 308 mg/L as CaCO₃, which is very hard. The value is measured (ARS health control, SISE-Eaux, August 2026). It is identical to the figure for Sotteville-lès-Rouen, served by the same metropolitan authority.
TH en °fH : douce < 15, moyennement dure 15–25, dure 25–35, très dure > 35 °fH (classes usuelles ARS).
Water data
| Total hardness | 30.8 °fH |
|---|---|
| Utility | Metropole Rouen Normandie |
How Saint-Étienne-du-Rouvray compares
- Tap water in Saint-Étienne-du-Rouvray is 29 % harder than the median of the 33641 cities we track in France (23.9 °fH).
- By hardness it ranks 7277 of 33641 in France (1 = hardest); 78 % of these cities have softer water.
- In Seine-Maritime it is number 50 of 682 cities; the regional median is 28.5 °fH.
- Nearest city with clearly softer water: Le Manoir, 10 km away (22.5 °fH).
- Nearest city with clearly harder water: Chérence, 52 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 Saint-Étienne-du-Rouvray
| 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 Saint-Étienne-du-Rouvray water hard or soft?
It is very hard: 308 mg/L as CaCO₃ (18 gpg, 17.3 °dH). The usual bands are soft < 60, moderately hard 60–120, hard 120–180 and very hard > 180 mg/L.
Is tap water in Saint-Étienne-du-Rouvray 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 Saint-Étienne-du-Rouvray water?
18 gpg, equal to 17.3 °dH, 30.8 °fH or 308 mg/L calcium carbonate.
What dishwasher salt setting should I use in Saint-Étienne-du-Rouvray?
For 308 mg/L (17.3 °dH) check your manufacturer's table: maximum level (5–7).
Do I need a water softener in Saint-Étienne-du-Rouvray?
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 76575 (2026-08). Method: own measurement. Ministère de la Santé (ARS), contrôle sanitaire SISE-Eaux, commune 76575 · Outdated figure? Tell us