Water hardness in Mérignac (Gironde)
20.2 °fH very hard
Tap water in Mérignac (Gironde) is very hard: 20.2 °fH (202 mg/L · 11.8 gpg · 11.3 °dH).
Source: Ministère de la Santé (ARS), contrôle sanitaire SISE-Eaux, commune 33281 (2026-08) · data checked 2026-10-19
Range across supply zones: 193–212 mg/L.
Mérignac is served by the Bordeaux Métropole water utility, which draws from the deep Gironde aquifers made of limestone and sand. The measured water gives 202.0 mg/L CaCO₃, between 193.0 and 212.0 mg/L. Scale is frequent without being extreme.
TH en °fH : douce < 15, moyennement dure 15–25, dure 25–35, très dure > 35 °fH (classes usuelles ARS).
Water data
| Total hardness | 20.2 °fH |
|---|---|
| Utility | Regie De L'Eau Bordeaux Metropole |
How Mérignac (Gironde) compares
- Tap water in Mérignac (Gironde) is 15 % softer than the median of the 33641 cities we track in France (23.9 °fH).
- By hardness it ranks 20190 of 33641 in France (1 = hardest); 40 % of these cities have softer water.
- In Gironde it is number 174 of 534 cities; the regional median is 17.5 °fH.
- Nearest city with clearly softer water: Martignas-sur-Jalle, 10 km away (13.4 °fH).
- Nearest city with clearly harder water: Bruges, 5 km away (25.9 °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 Mérignac
| 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 Mérignac (Gironde) water hard or soft?
It is very hard: 202 mg/L as CaCO₃ (11.8 gpg, 11.3 °dH). The usual bands are soft < 60, moderately hard 60–120, hard 120–180 and very hard > 180 mg/L.
Is tap water in Mérignac (Gironde) 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 Mérignac (Gironde) water?
11.8 gpg, equal to 11.3 °dH, 20.2 °fH or 202 mg/L calcium carbonate.
What dishwasher salt setting should I use in Mérignac (Gironde)?
For 202 mg/L (11.3 °dH) check your manufacturer's table: maximum level (5–7).
Do I need a water softener in Mérignac (Gironde)?
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 33281 (2026-08). Method: own measurement. Ministère de la Santé (ARS), contrôle sanitaire SISE-Eaux, commune 33281 · Outdated figure? Tell us