Water hardness in Idar-Oberstein
3.4 °dH moderately hard
Tap water in Idar-Oberstein is moderately hard: 3.4 °dH (61 mg/L · 3.5 gpg · 6.1 °fH).
Source: Stadtwerke Idar-Oberstein (2021-03) · data checked 2026-10-23
This figure is over 3 years old; hardness may have changed.
The figure of 60.7 mg/L CaCO₃ for Idar-Oberstein comes from a Stadtwerke analysis dated March 2021 and is marked as stale. We found no newer published value and no zone breakdown, so the current hardness may differ. Neighbouring regions such as Merzig (73.5 mg/L) and Pirmasens (70.1 mg/L) are also soft to moderate. Ask the utility for current data.
German law (WRMG) uses 3 bands: soft < 8.4 °dH, medium 8.4–14 °dH, hard > 14 °dH.
Water data
| Total hardness | 3.4 °dH |
|---|
How Idar-Oberstein compares
- Tap water in Idar-Oberstein is 70 % softer than the median of the 809 cities we track in Germany (11.5 °dH).
- By hardness it ranks 789 of 809 in Germany (1 = hardest); 2 % of these cities have softer water.
- In Rheinland-Pfalz it is number 23 of 25 cities; the regional median is 9.9 °dH.
- Nearest city with clearly softer water: Eberbach, 124 km away (2.1 °dH).
- Nearest city with clearly harder water: Sankt Wendel, 28 km away (6.4 °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 Idar-Oberstein
| Brand | Setting for this water |
|---|---|
| Bosch | H00 |
| Miele | 3 °dH |
| AEG / Electrolux | 1 |
| Beko | 1st |
| Hoover | S0 |
| LG | H0 |
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 Idar-Oberstein water hard or soft?
It is moderately hard: 61 mg/L as CaCO₃ (3.5 gpg, 3.4 °dH). The usual bands are soft < 60, moderately hard 60–120, hard 120–180 and very hard > 180 mg/L.
Is tap water in Idar-Oberstein 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 Idar-Oberstein water?
3.5 gpg, equal to 3.4 °dH, 6.1 °fH or 61 mg/L calcium carbonate.
What dishwasher salt setting should I use in Idar-Oberstein?
For 61 mg/L (3.4 °dH) check your manufacturer's table: level 2–3.
Do I need a water softener in Idar-Oberstein?
Not essential; a scale inhibitor protects the heater cheaply.
Source
Source: Stadtwerke Idar-Oberstein (2021-03). Method: older figure, source currently unavailable. Stadtwerke Idar-Oberstein · Outdated figure? Tell us