Water hardness in Lohmar
4.7 °dH moderately hard
Tap water in Lohmar is moderately hard: 4.7 °dH (84 mg/L · 4.9 gpg · 8.4 °fH).
Source: Wahnbachtalsperrenverband, Wasserchemische Beschaffenheit des abgegebenen Trinkwassers, Analysenwerte Jan-Dec 2025 (published by Stadtwerke Lohmar) (2025) · data checked 2026-10-23
Stadtwerke Lohmar publishes the 2025 analysis values of the Wahnbachtalsperrenverband, the regional water association that supplies the town. The result is 83.9 mg/L CaCO₃, in the moderate category and well below Cologne at 300.8 mg/L. Neighbouring Siegburg and Troisdorf report 85.7 and 96.4 mg/L. Scale builds up slowly 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 | 4.7 °dH |
|---|---|
| Utility | Stadtwerke Lohmar (water from Wahnbachtalsperrenverband) |
How Lohmar compares
- Tap water in Lohmar is 59 % softer than the median of the 809 cities we track in Germany (11.5 °dH).
- By hardness it ranks 741 of 809 in Germany (1 = hardest); 8 % of these cities have softer water.
- In Nordrhein-Westfalen it is number 143 of 153 cities; the regional median is 11.3 °dH.
- Nearest city with clearly softer water: Sprockhövel, 45 km away (3.5 °dH).
- Nearest city with clearly harder water: Rösrath, 7 km away (6.5 °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 Lohmar
| Brand | Setting for this water |
|---|---|
| Bosch | H00 |
| Miele | 5 °dH |
| AEG / Electrolux | 2 |
| Beko | 1st |
| 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 Lohmar water hard or soft?
It is moderately hard: 84 mg/L as CaCO₃ (4.9 gpg, 4.7 °dH). The usual bands are soft < 60, moderately hard 60–120, hard 120–180 and very hard > 180 mg/L.
Is tap water in Lohmar 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 Lohmar water?
4.9 gpg, equal to 4.7 °dH, 8.4 °fH or 84 mg/L calcium carbonate.
What dishwasher salt setting should I use in Lohmar?
For 84 mg/L (4.7 °dH) check your manufacturer's table: level 2–3.
Do I need a water softener in Lohmar?
Not essential; a scale inhibitor protects the heater cheaply.
Source
Source: Wahnbachtalsperrenverband, Wasserchemische Beschaffenheit des abgegebenen Trinkwassers, Analysenwerte Jan-Dec 2025 (published by Stadtwerke Lohmar) (2025). Method: figure published by the water supplier. Wahnbachtalsperrenverband, Wasserchemische Beschaffenheit des abgegebenen Trinkwassers, Analysenwerte Jan-Dec 2025 (published by Stadtwerke Lohmar) · Outdated figure? Tell us