Water hardness in Royan
34.1 °fH very hard
Tap water in Royan is very hard: 34.1 °fH (341 mg/L · 19.9 gpg · 19.1 °dH).
Source: Ministère de la Santé (ARS), contrôle sanitaire SISE-Eaux, commune 17306 (2026-08) · data checked 2026-10-19
Royan in Charente-Maritime is served by SEPRA. The Charente coast sits on Cretaceous limestone, and the water is very hard: 341 mg/L CaCO₃. The exact source is not detailed here; scale builds up quickly in water heaters.
TH en °fH : douce < 15, moyennement dure 15–25, dure 25–35, très dure > 35 °fH (classes usuelles ARS).
Water data
| Total hardness | 34.1 °fH |
|---|---|
| Utility | S.E.P.R.A. |
How Royan compares
- Tap water in Royan is 43 % harder than the median of the 33641 cities we track in France (23.9 °fH).
- By hardness it ranks 3539 of 33641 in France (1 = hardest); 89 % of these cities have softer water.
- In Charente-Maritime it is number 138 of 460 cities; the regional median is 32.9 °fH.
- Nearest city with clearly softer water: Le Verdon-sur-Mer, 9 km away (17.6 °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 Royan
| Brand | Setting for this water |
|---|---|
| Bosch | H05 |
| Miele | 19 °dH |
| AEG / Electrolux | 5 |
| 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 Royan water hard or soft?
It is very hard: 341 mg/L as CaCO₃ (19.9 gpg, 19.1 °dH). The usual bands are soft < 60, moderately hard 60–120, hard 120–180 and very hard > 180 mg/L.
Is tap water in Royan 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 Royan water?
19.9 gpg, equal to 19.1 °dH, 34.1 °fH or 341 mg/L calcium carbonate.
What dishwasher salt setting should I use in Royan?
For 341 mg/L (19.1 °dH) check your manufacturer's table: maximum level (5–7).
Do I need a water softener in Royan?
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 17306 (2026-08). Method: own measurement. Ministère de la Santé (ARS), contrôle sanitaire SISE-Eaux, commune 17306 · Outdated figure? Tell us