Water hardness in Słupsk
208 mg/L very hard
Tap water in Słupsk is very hard: 208 mg/L (12.1 gpg · 11.7 °dH · 20.8 °fH).
Source: Wodociągi Słupsk, Wyniki badań jakości wody w Słupsku w 2025 roku (wartości uśrednione) (2025) · data checked 2026-10-29
Wodociągi Słupsk publishes averaged results for 2025, giving 208 mg/L CaCO₃ for the city. That is the lowest of the very hard values in this batch, but still above the very hard threshold. Because the figure is an annual average, individual months can differ somewhat. Scale on heating elements is the main practical effect.
Polish suppliers report total hardness in mg/L CaCO₃; the drinking-water regulation range is 60–500 mg/L.
Water data
| Total hardness | 208 mg/L |
|---|---|
| Utility | Wodociągi Słupsk Sp. z o.o. |
How Słupsk compares
- Tap water in Słupsk is 15 % softer than the median of the 91 cities we track in Poland (245 mg/L).
- By hardness it ranks 64 of 91 in Poland (1 = hardest); 29 % of these cities have softer water.
- In pomorskie it is number 5 of 7 cities; the regional median is 220 mg/L.
- Nearest city with clearly harder water: Koszalin, 63 km away (267 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 Słupsk
| Brand | Setting for this water |
|---|---|
| Bosch | H03 |
| Miele | 12 °dH |
| AEG / Electrolux | 3 |
| Beko | 3rd |
| Hoover | S2 |
| LG | H2 |
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 Słupsk water hard or soft?
It is very hard: 208 mg/L as CaCO₃ (12.1 gpg, 11.7 °dH). The usual bands are soft < 60, moderately hard 60–120, hard 120–180 and very hard > 180 mg/L.
Is tap water in Słupsk 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 Słupsk water?
12.1 gpg, equal to 11.7 °dH, 20.8 °fH or 208 mg/L calcium carbonate.
What dishwasher salt setting should I use in Słupsk?
For 208 mg/L (11.7 °dH) check your manufacturer's table: maximum level (5–7).
Do I need a water softener in Słupsk?
Yes, unless you are only passing through: scale damages appliances within a few years.
Source
Source: Wodociągi Słupsk, Wyniki badań jakości wody w Słupsku w 2025 roku (wartości uśrednione) (2025). Method: figure published by the water supplier. Wodociągi Słupsk, Wyniki badań jakości wody w Słupsku w 2025 roku (wartości uśrednione) · Outdated figure? Tell us