Water hardness in Colmar
27.4 °fH very hard
Tap water in Colmar is very hard: 27.4 °fH (274 mg/L · 16 gpg · 15.4 °dH).
Source: Ministère de la Santé (ARS), contrôle sanitaire SISE-Eaux, commune 68066 (2026-08) · data checked 2026-10-19
Range across supply zones: 255–293 mg/L.
Colmar's water is drawn from the Rhine aquifer, under the Alsace plain, and from resources at the foot of the Vosges. Alluvium from the Rhine and the Vosges gives it 274.0 mg/L CaCO₃, between 255.0 and 293.0 mg/L. Scale leaves white deposits on taps.
TH en °fH : douce < 15, moyennement dure 15–25, dure 25–35, très dure > 35 °fH (classes usuelles ARS).
Water data
| Total hardness | 27.4 °fH |
|---|---|
| Utility | Colmarienne Des Eaux |
How Colmar compares
- Tap water in Colmar is 15 % harder than the median of the 33641 cities we track in France (23.9 °fH).
- By hardness it ranks 12301 of 33641 in France (1 = hardest); 63 % of these cities have softer water.
- In Haut-Rhin it is number 120 of 360 cities; the regional median is 22.6 °fH.
- Nearest city with clearly softer water: Eguisheim, 6 km away (21.8 °fH).
- Nearest city with clearly harder water: Bruebach, 42 km away (49.4 °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 Colmar
| Brand | Setting for this water |
|---|---|
| Bosch | H04 |
| Miele | 15 °dH |
| AEG / Electrolux | 4 |
| Beko | 4th |
| Hoover | S2 |
| 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 Colmar water hard or soft?
It is very hard: 274 mg/L as CaCO₃ (16 gpg, 15.4 °dH). The usual bands are soft < 60, moderately hard 60–120, hard 120–180 and very hard > 180 mg/L.
Is tap water in Colmar 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 Colmar water?
16 gpg, equal to 15.4 °dH, 27.4 °fH or 274 mg/L calcium carbonate.
What dishwasher salt setting should I use in Colmar?
For 274 mg/L (15.4 °dH) check your manufacturer's table: maximum level (5–7).
Do I need a water softener in Colmar?
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 68066 (2026-08). Method: own measurement. Ministère de la Santé (ARS), contrôle sanitaire SISE-Eaux, commune 68066 · Outdated figure? Tell us