Water hardness in Warendorf
14.4 °dH very hard
Tap water in Warendorf is very hard: 14.4 °dH (257 mg/L · 15 gpg · 25.7 °fH).
Source: Stadtwerke Warendorf – Häufige Fragen (2026) · data checked 2026-10-23
Stadtwerke Warendorf gives one hardness value for its supply, 257.0 mg/L CaCO₃ (2.55 mmol/L), in its FAQ page. The utility does not split it into zones there. Nearby Ahlen and Hamm are listed at about 130 to 140 mg/L, so the figure changes noticeably over a short distance.
German law (WRMG) uses 3 bands: soft < 8.4 °dH, medium 8.4–14 °dH, hard > 14 °dH.
Water data
| Total hardness | 14.4 °dH |
|---|---|
| mmol_l | 2.55 |
| Utility | Stadtwerke Warendorf |
How Warendorf compares
- Tap water in Warendorf is 25 % harder than the median of the 809 cities we track in Germany (11.5 °dH).
- By hardness it ranks 279 of 809 in Germany (1 = hardest); 65 % of these cities have softer water.
- In Nordrhein-Westfalen it is number 34 of 153 cities; the regional median is 11.3 °dH.
- Nearest city with clearly softer water: Ahlen, 22 km away (7.2 °dH).
- Nearest city with clearly harder water: Bad Rothenfelde, 17 km away (19.3 °dH).
Ranking of the hardest and softest water in Germany →
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 Warendorf
| 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 Warendorf water hard or soft?
It is very hard: 257 mg/L as CaCO₃ (15 gpg, 14.4 °dH). The usual bands are soft < 60, moderately hard 60–120, hard 120–180 and very hard > 180 mg/L.
Is tap water in Warendorf safe to drink?
Hardness is not a health issue; it is about limescale, taste and appliances. Mains water must meet national drinking-water standards. German law (WRMG) uses 3 bands: soft < 8.4 °dH, medium 8.4–14 °dH, hard > 14 °dH.
How many grains per gallon is Warendorf water?
15 gpg, equal to 14.4 °dH, 25.7 °fH or 257 mg/L calcium carbonate.
What dishwasher salt setting should I use in Warendorf?
For 257 mg/L (14.4 °dH) check your manufacturer's table: maximum level (5–7).
Do I need a water softener in Warendorf?
Yes, unless you are only passing through: scale damages appliances within a few years.
Source
Source: Stadtwerke Warendorf – Häufige Fragen (2026). Method: figure published by the water supplier. Stadtwerke Warendorf – Häufige Fragen · Outdated figure? Tell us