Water hardness in Terezín
4.27 mmol/L very hard
Tap water in Terezín is very hard: 4.27 mmol/L (427 mg/L · 24.9 gpg · 23.9 °dH).
Source: SčVK, Moje obec – kvalita vody (aktuální hodnoty) (2026) · data checked 2026-10-21
Range across supply zones: 422–431 mg/L.
Czech suppliers report "Vápník a hořčík" in mmol/L; the recommended range is 2–3.5 mmol/L.
Water data
| Total hardness | 4.27 mmol/L |
|---|---|
| Calcium (mg/L) | 146.5 |
| Magnesium (mg/L) | 14.9 |
| Utility | Severočeské vodovody a kanalizace, a.s. (SčVK) |
How Terezín compares
- Tap water in Terezín is 255 % harder than the median of the 1516 cities we track in Czechia (1.2 mmol/L).
- By hardness it ranks 126 of 1516 in Czechia (1 = hardest); 92 % of these cities have softer water.
- In Ústecký kraj it is number 124 of 631 cities; the regional median is 1.31 mmol/L.
- Nearest city with clearly softer water: Litoměřice, 3 km away (3.4 mmol/L).
- Nearest city with clearly harder water: Siřejovice, 7 km away (6.13 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 Terezín
| Brand | Setting for this water |
|---|---|
| Bosch | H06 |
| Miele | 24 °dH |
| AEG / Electrolux | 6 |
| Beko | 6th |
| Hoover | S3 |
| LG | H4 |
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 Terezín water hard or soft?
It is very hard: 427 mg/L as CaCO₃ (24.9 gpg, 23.9 °dH). The usual bands are soft < 60, moderately hard 60–120, hard 120–180 and very hard > 180 mg/L.
Is tap water in Terezín 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 Terezín water?
24.9 gpg, equal to 23.9 °dH, 42.7 °fH or 427 mg/L calcium carbonate.
What dishwasher salt setting should I use in Terezín?
For 427 mg/L (23.9 °dH) check your manufacturer's table: maximum level (5–7).
Do I need a water softener in Terezín?
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