Water hardness in Modra
3.72 mmol/L very hard
Tap water in Modra is very hard: 3.72 mmol/L (372 mg/L · 21.7 gpg · 20.9 °dH).
Source: Bratislavská vodárenská spoločnosť (BVS) (2026) · data checked 2026-10-20
Slovak suppliers report "Vápnik a horčík" in mmol/L; the recommended range is 1.1–5 mmol/L.
Water data
| Total hardness | 3.72 mmol/L |
|---|---|
| Utility | Bratislavská vodárenská spoločnosť (BVS) |
How Modra compares
- Tap water in Modra is 96 % harder than the median of the 1113 cities we track in Slovakia (1.9 mmol/L).
- By hardness it ranks 113 of 1113 in Slovakia (1 = hardest); 90 % of these cities have softer water.
- In Bratislava Region it is number 3 of 61 cities; the regional median is 2.13 mmol/L.
- Nearest city with clearly softer water: Vinosady, 3 km away (2.32 mmol/L).
- Nearest city with clearly harder water: Dolné Lovčice, 28 km away (5 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 Modra
| Brand | Setting for this water |
|---|---|
| Bosch | H05 |
| Miele | 21 °dH |
| AEG / Electrolux | 5 |
| 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 Modra water hard or soft?
It is very hard: 372 mg/L as CaCO₃ (21.7 gpg, 20.9 °dH). The usual bands are soft < 60, moderately hard 60–120, hard 120–180 and very hard > 180 mg/L.
Is tap water in Modra 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 Modra water?
21.7 gpg, equal to 20.9 °dH, 37.2 °fH or 372 mg/L calcium carbonate.
What dishwasher salt setting should I use in Modra?
For 372 mg/L (20.9 °dH) check your manufacturer's table: maximum level (5–7).
Do I need a water softener in Modra?
Yes, unless you are only passing through: scale damages appliances within a few years.
Source
Source: Bratislavská vodárenská spoločnosť (BVS) (2026). Method: figure published by the water supplier. Bratislavská vodárenská spoločnosť (BVS) · Outdated figure? Tell us