Water hardness in Košice
1.17 mmol/L moderately hard
Tap water in Košice is moderately hard: 1.17 mmol/L (117 mg/L · 6.8 gpg · 6.6 °dH).
Source: Východoslovenská vodárenská spoločnosť (VVS) (2025) · data checked 2026-10-20
Range across supply zones: 65–356 mg/L.
VVS supplies Košice and much of eastern Slovakia, where the Starina reservoir on the upper Cirocha is the main surface source of the wider system and local wells and springs are also used. The reported hardness is 117.1 mg/L CaCO₃, with measurements from 65.1 to 356.3 mg/L. Limescale appears gradually on taps and heating elements; occasional descaling keeps it in check.
Slovak suppliers report "Vápnik a horčík" in mmol/L; the recommended range is 1.1–5 mmol/L.
Water data
| Total hardness | 1.17 mmol/L |
|---|---|
| Utility | Východoslovenská vodárenská spoločnosť (VVS) |
How Košice compares
- Tap water in Košice is 38 % softer than the median of the 1113 cities we track in Slovakia (1.9 mmol/L).
- By hardness it ranks 792 of 1113 in Slovakia (1 = hardest); 29 % of these cities have softer water.
- In Košice Region it is number 218 of 300 cities; the regional median is 1.28 mmol/L.
- Nearest city with clearly softer water: Baška, 6 km away (0.77 mmol/L).
- Nearest city with clearly harder water: Kostoľany nad Hornádom, 9 km away (3.59 mmol/L).
Ranking of the hardest and softest water in Slovakia →
What it means at home
- Visible kettle scale every few weeks; vinegar or citric acid is enough.
- Water heater and washing machine: some long-term scale; a scale inhibitor slows it.
- Dishwasher: medium salt setting.
- Softener optional; pays off mainly with a gas boiler or tankless heater.
How much salt will you use for softening?
Optional. A scale inhibitor or a small softener protects the heater; soap savings are modest.
Descale a coffee machine or kettle about every 3 months (typical manufacturer guidance for this hardness).
Estimates for planning, not a quote. Check your appliance manual for exact settings.
Dishwasher setting in Košice
| Brand | Setting for this water |
|---|---|
| Bosch | H01 |
| Miele | 7 °dH |
| AEG / Electrolux | 2 |
| Beko | 2nd |
| Hoover | S1 |
| LG | H1 |
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 Košice water hard or soft?
It is moderately hard: 117 mg/L as CaCO₃ (6.8 gpg, 6.6 °dH). The usual bands are soft < 60, moderately hard 60–120, hard 120–180 and very hard > 180 mg/L.
Is tap water in Košice 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 Košice water?
6.8 gpg, equal to 6.6 °dH, 11.7 °fH or 117 mg/L calcium carbonate.
What dishwasher salt setting should I use in Košice?
For 117 mg/L (6.6 °dH) check your manufacturer's table: level 2–3.
Do I need a water softener in Košice?
Not essential; a scale inhibitor protects the heater cheaply.
Source
Source: Východoslovenská vodárenská spoločnosť (VVS) (2025). Method: figure published by the water supplier. Východoslovenská vodárenská spoločnosť (VVS) · Outdated figure? Tell us