Water hardness in Roštár
2.5 mmol/L very hard
Tap water in Roštár is very hard: 2.5 mmol/L (250 mg/L · 14.6 gpg · 14 °dH).
Source: Východoslovenská vodárenská spoločnosť (VVS) (2025) · data checked 2026-10-20
Range across supply zones: 249–251 mg/L.
Slovak suppliers report "Vápnik a horčík" in mmol/L; the recommended range is 1.1–5 mmol/L.
Water data
| Total hardness | 2.5 mmol/L |
|---|---|
| Utility | Východoslovenská vodárenská spoločnosť (VVS) |
How Roštár compares
- Tap water in Roštár is 32 % harder than the median of the 1113 cities we track in Slovakia (1.9 mmol/L).
- By hardness it ranks 382 of 1113 in Slovakia (1 = hardest); 65 % of these cities have softer water.
- In Košice Region it is number 55 of 300 cities; the regional median is 1.28 mmol/L.
- Nearest city with clearly softer water: Ochtiná, 2 km away (1.84 mmol/L).
- Nearest city with clearly harder water: Čučma, 14 km away (3.17 mmol/L).
Ranking of the hardest and softest water in Slovakia →
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 Roštár
| Brand | Setting for this water |
|---|---|
| Bosch | H04 |
| Miele | 14 °dH |
| AEG / Electrolux | 3 |
| 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 Roštár water hard or soft?
It is very hard: 250 mg/L as CaCO₃ (14.6 gpg, 14 °dH). The usual bands are soft < 60, moderately hard 60–120, hard 120–180 and very hard > 180 mg/L.
Is tap water in Roštár safe to drink?
Hardness is not a health issue; it is about limescale, taste and appliances. Mains water must meet national drinking-water standards. Slovak suppliers report "Vápnik a horčík" in mmol/L; the recommended range is 1.1–5 mmol/L.
How many grains per gallon is Roštár water?
14.6 gpg, equal to 14 °dH, 25 °fH or 250 mg/L calcium carbonate.
What dishwasher salt setting should I use in Roštár?
For 250 mg/L (14 °dH) check your manufacturer's table: maximum level (5–7).
Do I need a water softener in Roštár?
Yes, unless you are only passing through: scale damages appliances within a few years.
Source
Source: Východoslovenská vodárenská spoločnosť (VVS) (2025). Method: figure published by the water supplier. Východoslovenská vodárenská spoločnosť (VVS) · Outdated figure? Tell us