Water hardness in Saint-Priest (Rhône)
20.4 °fH very hard
Tap water in Saint-Priest (Rhône) is very hard: 20.4 °fH (204 mg/L · 11.9 gpg · 11.4 °dH).
Source: Ministère de la Santé (ARS), contrôle sanitaire SISE-Eaux, commune 69290 (2026-08) · data checked 2026-10-19
Saint-Priest is served by Eau du Grand Lyon, whose water comes mainly from the Rhône alluvial aquifer at the Crépieux-Charmy wellfield. This Alpine-origin water measures 204.0 mg/L CaCO₃: a hardness slightly higher than in central Lyon.
TH en °fH : douce < 15, moyennement dure 15–25, dure 25–35, très dure > 35 °fH (classes usuelles ARS).
Water data
| Total hardness | 20.4 °fH |
|---|---|
| Utility | Eau Du Grand Lyon |
How Saint-Priest (Rhône) compares
- Tap water in Saint-Priest (Rhône) is 15 % softer than the median of the 33641 cities we track in France (23.9 °fH).
- By hardness it ranks 20017 of 33641 in France (1 = hardest); 40 % of these cities have softer water.
- In Rhône it is number 125 of 231 cities; the regional median is 22.4 °fH.
- Nearest city with clearly softer water: Courzieu, 29 km away (13.3 °fH).
- Nearest city with clearly harder water: Chaponnay, 8 km away (29.7 °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-Priest
| Brand | Setting for this water |
|---|---|
| Bosch | H03 |
| Miele | 11 °dH |
| AEG / Electrolux | 3 |
| Beko | 3rd |
| Hoover | S2 |
| LG | H2 |
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-Priest (Rhône) water hard or soft?
It is very hard: 204 mg/L as CaCO₃ (11.9 gpg, 11.4 °dH). The usual bands are soft < 60, moderately hard 60–120, hard 120–180 and very hard > 180 mg/L.
Is tap water in Saint-Priest (Rhône) 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-Priest (Rhône) water?
11.9 gpg, equal to 11.4 °dH, 20.4 °fH or 204 mg/L calcium carbonate.
What dishwasher salt setting should I use in Saint-Priest (Rhône)?
For 204 mg/L (11.4 °dH) check your manufacturer's table: maximum level (5–7).
Do I need a water softener in Saint-Priest (Rhône)?
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 69290 (2026-08). Method: own measurement. Ministère de la Santé (ARS), contrôle sanitaire SISE-Eaux, commune 69290 · Outdated figure? Tell us