Water hardness in Troisdorf
5.4 °dH moderately hard
Tap water in Troisdorf is moderately hard: 5.4 °dH (96 mg/L · 5.6 gpg · 9.6 °fH).
Source: Stadtwerke Troisdorf Pruefbericht WW Eschmar, Probe-Nr. 202509340 (RheinEnergie Wasserlabor) (2025-05) · data checked 2026-10-20
The Troisdorf figure is a lab report for the Eschmar waterworks, sampled on 13 May 2025, with 96.4 mg/L CaCO₃ calculated. The utility's web page describes the water as very soft, which agrees. Other waterworks were not checked, so the value is treated as citywide with that caveat. A softener is rarely needed at this level.
German law (WRMG) uses 3 bands: soft < 8.4 °dH, medium 8.4–14 °dH, hard > 14 °dH.
Water data
| Total hardness | 5.4 °dH |
|---|---|
| Utility | Stadtwerke Troisdorf GmbH |
How Troisdorf compares
- Tap water in Troisdorf is 53 % softer than the median of the 809 cities we track in Germany (11.5 °dH).
- By hardness it ranks 721 of 809 in Germany (1 = hardest); 11 % of these cities have softer water.
- In Nordrhein-Westfalen it is number 138 of 153 cities; the regional median is 11.3 °dH.
- Nearest city with clearly softer water: Sprockhövel, 48 km away (3.5 °dH).
- Nearest city with clearly harder water: Bornheim (Rhein-Sieg), 6 km away (12 °dH).
Ranking of the hardest and softest water in Germany →
What it means at home
- Visible kettle scale every few weeks; vinegar or citric acid is enough.
- Water heater and washing machine: some long-term scale; a scale inhibitor slows it.
- Dishwasher: medium salt setting.
- Softener optional; pays off mainly with a gas boiler or tankless heater.
How much salt will you use for softening?
Optional. A scale inhibitor or a small softener protects the heater; soap savings are modest.
Descale a coffee machine or kettle about every 3 months (typical manufacturer guidance for this hardness).
Estimates for planning, not a quote. Check your appliance manual for exact settings.
Dishwasher setting in Troisdorf
| Brand | Setting for this water |
|---|---|
| Bosch | H00 |
| Miele | 5 °dH |
| AEG / Electrolux | 2 |
| Beko | 2nd |
| Hoover | S1 |
| LG | H1 |
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 Troisdorf water hard or soft?
It is moderately hard: 96 mg/L as CaCO₃ (5.6 gpg, 5.4 °dH). The usual bands are soft < 60, moderately hard 60–120, hard 120–180 and very hard > 180 mg/L.
Is tap water in Troisdorf 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 Troisdorf water?
5.6 gpg, equal to 5.4 °dH, 9.6 °fH or 96 mg/L calcium carbonate.
What dishwasher salt setting should I use in Troisdorf?
For 96 mg/L (5.4 °dH) check your manufacturer's table: level 2–3.
Do I need a water softener in Troisdorf?
Not essential; a scale inhibitor protects the heater cheaply.
Source
Source: Stadtwerke Troisdorf Pruefbericht WW Eschmar, Probe-Nr. 202509340 (RheinEnergie Wasserlabor) (2025-05). Method: figure published by the water supplier. Stadtwerke Troisdorf Pruefbericht WW Eschmar, Probe-Nr. 202509340 (RheinEnergie Wasserlabor) · Outdated figure? Tell us