Water hardness in Warsaw
251 mg/L very hard
Tap water in Warsaw is very hard: 251 mg/L (14.7 gpg · 14.1 °dH · 25.1 °fH).
Source: MPWiK m.st. Warszawy S.A. (2026) · data checked 2026-10-21
Range across supply zones: 174–362 mg/L.
4 supply zones — hardness varies by neighbourhood; the figure above is the median.
Hardness by district / supply zone
| mg/L | mg/L | ||
|---|---|---|---|
| Dzielnica Wawer | 196 | 196 | very hard |
| Dzielnica Wesoła | 347 | 347 | very hard |
| Zakład Centralny (SUW Filtry, SUW Praga) | 243 | 243 | very hard |
| Zakład Północny | 260 | 260 | very hard |
MPWiK Warsaw publishes hardness per treatment plant, not per street. Its first-half 2026 table gives plant averages of 241.3 to 260 mg/L CaCO₃ for the central and northern plants, and single values of 174 to 362 mg/L for the Wawer and Wesoła plants. The city median is 251.3 mg/L, so most of Warsaw has very hard water. Check which plant serves your district before sizing a softener. The utility does not say what geology sits behind the figures.
Polish suppliers report total hardness in mg/L CaCO₃; the drinking-water regulation range is 60–500 mg/L.
Water data
| Total hardness | 251 mg/L |
|---|---|
| Utility | MPWiK m.st. Warszawy S.A. |
How Warsaw compares
- Tap water in Warsaw is close to the median of the 91 cities we track in Poland (245 mg/L).
- By hardness it ranks 42 of 91 in Poland (1 = hardest); 54 % of these cities have softer water.
- In mazowieckie it is number 7 of 17 cities; the regional median is 251 mg/L.
- Nearest city with clearly softer water: Wawer, 12 km away (196 mg/L).
- Nearest city with clearly harder water: Ciechanów, 77 km away (338 mg/L).
Ranking of the hardest and softest water in Poland →
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 Warsaw
| 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 Warsaw water hard or soft?
It is very hard: 251 mg/L as CaCO₃ (14.7 gpg, 14.1 °dH). The usual bands are soft < 60, moderately hard 60–120, hard 120–180 and very hard > 180 mg/L.
Is tap water in Warsaw safe to drink?
Hardness is not a health issue; it is about limescale, taste and appliances. Mains water must meet national drinking-water standards. Polish suppliers report total hardness in mg/L CaCO₃; the drinking-water regulation range is 60–500 mg/L.
How many grains per gallon is Warsaw water?
14.7 gpg, equal to 14.1 °dH, 25.1 °fH or 251 mg/L calcium carbonate.
What dishwasher salt setting should I use in Warsaw?
For 251 mg/L (14.1 °dH) check your manufacturer's table: maximum level (5–7).
Do I need a water softener in Warsaw?
Yes, unless you are only passing through: scale damages appliances within a few years.
Source
Source: MPWiK m.st. Warszawy S.A. (2026). Method: figure published by the water supplier. MPWiK m.st. Warszawy S.A. · Outdated figure? Tell us