Water hardness in Poznań
320 mg/L very hard
Tap water in Poznań is very hard: 320 mg/L (18.7 gpg · 17.9 °dH · 32 °fH).
Source: Aquanet S.A., Jakość wody do picia ze stacji uzdatniania, III kwartał 2026 (XLSX) (2026) · data checked 2026-10-23
Range across supply zones: 240–350 mg/L.
3 supply zones — hardness varies by neighbourhood; the figure above is the median.
Hardness by district / supply zone
| mg/L | mg/L | ||
|---|---|---|---|
| SUW Gruszczyn (eastern supply) | 320 | 320 | very hard |
| SUW Mosina (Mosina-Krajkowo intake, about 70% of Poznań per Aquanet) | 350 | 350 | very hard |
| SUW Poznań (ul. Wiśniowa, Dębina intake) | 240 | 240 | very hard |
Poznań draws mainly on the Warta valley, including infiltration intakes near Mosina. The figure shown, 320.0 mg/L CaCO₃, is the median across 3 supply zones, which range from 240.0 to 350.0 mg/L, so it depends on which zone your street is in. Limescale builds quickly in kettles, boilers and washing machines, so frequent descaling or a softener is worth considering.
Polish suppliers report total hardness in mg/L CaCO₃; the drinking-water regulation range is 60–500 mg/L.
Water data
| Total hardness | 320 mg/L |
|---|---|
| Utility | Aquanet S.A. |
How Poznań compares
- Tap water in Poznań is 31 % harder than the median of the 91 cities we track in Poland (245 mg/L).
- By hardness it ranks 12 of 91 in Poland (1 = hardest); 88 % of these cities have softer water.
- In wielkopolskie it is number 3 of 5 cities; the regional median is 320 mg/L.
- Nearest city with clearly softer water: Głogów, 101 km away (245 mg/L).
- Nearest city with clearly harder water: Fordon, 117 km away (404 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 Poznań
| Brand | Setting for this water |
|---|---|
| Bosch | H05 |
| Miele | 18 °dH |
| AEG / Electrolux | 4 |
| Beko | 5th |
| Hoover | S3 |
| 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 Poznań water hard or soft?
It is very hard: 320 mg/L as CaCO₃ (18.7 gpg, 17.9 °dH). The usual bands are soft < 60, moderately hard 60–120, hard 120–180 and very hard > 180 mg/L.
Is tap water in Poznań 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 Poznań water?
18.7 gpg, equal to 17.9 °dH, 32 °fH or 320 mg/L calcium carbonate.
What dishwasher salt setting should I use in Poznań?
For 320 mg/L (17.9 °dH) check your manufacturer's table: maximum level (5–7).
Do I need a water softener in Poznań?
Yes, unless you are only passing through: scale damages appliances within a few years.
Source
Source: Aquanet S.A., Jakość wody do picia ze stacji uzdatniania, III kwartał 2026 (XLSX) (2026). Method: figure published by the water supplier. Aquanet S.A., Jakość wody do picia ze stacji uzdatniania, III kwartał 2026 (XLSX) · Outdated figure? Tell us