Water hardness in Riom
6.8 °fH moderately hard
Tap water in Riom is moderately hard: 6.8 °fH (68 mg/L · 4 gpg · 3.8 °dH).
Source: Ministère de la Santé (ARS), contrôle sanitaire SISE-Eaux, commune 63300 (2026-08) · data checked 2026-10-19
Riom is served by Semerap in Auvergne, on the Limagne plain at the foot of the Chaîne des Puys. Volcanic and granitic rocks supply little limestone: 68 mg/L CaCO₃, fairly soft water. Scale is uncommon.
TH en °fH : douce < 15, moyennement dure 15–25, dure 25–35, très dure > 35 °fH (classes usuelles ARS).
Water data
| Total hardness | 6.8 °fH |
|---|---|
| Utility | S.E.M.E.R.A.P. |
How Riom compares
- Tap water in Riom is 72 % softer than the median of the 33641 cities we track in France (23.9 °fH).
- By hardness it ranks 31219 of 33641 in France (1 = hardest); 7 % of these cities have softer water.
- In Puy-de-Dôme it is number 163 of 419 cities; the regional median is 5.3 °fH.
- Nearest city with clearly softer water: Durtol, 12 km away (5.1 °fH).
- Nearest city with clearly harder water: Ménétrol, 3 km away (8.7 °fH).
Ranking of the hardest and softest water in France →
What it means at home
- Visible kettle scale every few weeks; vinegar or citric acid is enough.
- Water heater and washing machine: some long-term scale; a scale inhibitor slows it.
- Dishwasher: medium salt setting.
- Softener optional; pays off mainly with a gas boiler or tankless heater.
How much salt will you use for softening?
Optional. A scale inhibitor or a small softener protects the heater; soap savings are modest.
Descale a coffee machine or kettle about every 3 months (typical manufacturer guidance for this hardness).
Estimates for planning, not a quote. Check your appliance manual for exact settings.
Dishwasher setting in Riom
| Brand | Setting for this water |
|---|---|
| Bosch | H00 |
| Miele | 4 °dH |
| AEG / Electrolux | 2 |
| Beko | 1st |
| Hoover | S1 |
| LG | H1 |
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 Riom water hard or soft?
It is moderately hard: 68 mg/L as CaCO₃ (4 gpg, 3.8 °dH). The usual bands are soft < 60, moderately hard 60–120, hard 120–180 and very hard > 180 mg/L.
Is tap water in Riom 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 Riom water?
4 gpg, equal to 3.8 °dH, 6.8 °fH or 68 mg/L calcium carbonate.
What dishwasher salt setting should I use in Riom?
For 68 mg/L (3.8 °dH) check your manufacturer's table: level 2–3.
Do I need a water softener in Riom?
Not essential; a scale inhibitor protects the heater cheaply.
Source
Source: Ministère de la Santé (ARS), contrôle sanitaire SISE-Eaux, commune 63300 (2026-08). Method: own measurement. Ministère de la Santé (ARS), contrôle sanitaire SISE-Eaux, commune 63300 · Outdated figure? Tell us