Water hardness in Doubí
2.43 mmol/L very hard
Tap water in Doubí is very hard: 2.43 mmol/L (243 mg/L · 14.2 gpg · 13.6 °dH).
Source: SčVK, Moje obec – kvalita vody (aktuální hodnoty) (2026) · data checked 2026-10-21
Range across supply zones: 243–408 mg/L.
SčVK reports a median of 243.2 mg/L as CaCO₃ for Doubí in the Liberec area, with a published range of 243.2 to 408.4 mg/L. That is very hard, and the wide range suggests more than one supply or changing conditions. The utility page does not explain which, so check the current value. Scale control is worthwhile at the upper end.
Czech suppliers report "Vápník a hořčík" in mmol/L; the recommended range is 2–3.5 mmol/L.
Water data
| Total hardness | 2.43 mmol/L |
|---|---|
| Calcium (mg/L) | 94 |
| Magnesium (mg/L) | 2 |
| Utility | Severočeské vodovody a kanalizace, a.s. (SčVK) |
How Doubí compares
- Tap water in Doubí is 102 % harder than the median of the 1516 cities we track in Czechia (1.2 mmol/L).
- By hardness it ranks 292 of 1516 in Czechia (1 = hardest); 81 % of these cities have softer water.
- In Liberecký kraj it is number 55 of 273 cities; the regional median is 1.26 mmol/L.
- Nearest city with clearly softer water: Borek, 6 km away (0.75 mmol/L).
- Nearest city with clearly harder water: Čtveřín, 1 km away (3.34 mmol/L).
Ranking of the hardest and softest water in Czechia →
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 Doubí
| Brand | Setting for this water |
|---|---|
| Bosch | H04 |
| Miele | 14 °dH |
| AEG / Electrolux | 3 |
| Beko | 4th |
| 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 Doubí water hard or soft?
It is very hard: 243 mg/L as CaCO₃ (14.2 gpg, 13.6 °dH). The usual bands are soft < 60, moderately hard 60–120, hard 120–180 and very hard > 180 mg/L.
Is tap water in Doubí safe to drink?
Hardness is not a health issue; it is about limescale, taste and appliances. Mains water must meet national drinking-water standards. Czech suppliers report "Vápník a hořčík" in mmol/L; the recommended range is 2–3.5 mmol/L.
How many grains per gallon is Doubí water?
14.2 gpg, equal to 13.6 °dH, 24.3 °fH or 243 mg/L calcium carbonate.
What dishwasher salt setting should I use in Doubí?
For 243 mg/L (13.6 °dH) check your manufacturer's table: maximum level (5–7).
Do I need a water softener in Doubí?
Yes, unless you are only passing through: scale damages appliances within a few years.
Source
Source: SčVK, Moje obec – kvalita vody (aktuální hodnoty) (2026). Method: figure published by the water supplier. SčVK, Moje obec – kvalita vody (aktuální hodnoty) · Outdated figure? Tell us