Water hardness in Tongeren
33.9 °fH very hard
Tap water in Tongeren is very hard: 33.9 °fH (339 mg/L · 19.8 gpg · 19 °dH).
Source: VMM, Kwaliteit van het drinkwater per leveringsgebied 2024, bijlage 2 (mediane concentratie) (2024) · data checked 2026-10-19
Range across supply zones: 76–432 mg/L.
De Watergroep supplies this part of Flanders with groundwater and surface water; where the water passes through chalk and limestone layers or blends with canal water, hardness is higher. The 2024 figure is 339.4 mg/L CaCO₃, within a reported range of 76.0 to 431.6 mg/L, so the exact value depends on your street. This is very hard water: expect heavy limescale on taps, glass and heating elements, and higher detergent and descaling needs.
Belgian suppliers report hardness in °f (French degrees); 1 °f = 10 mg/L CaCO₃.
Water data
| Total hardness | 33.9 °fH |
|---|---|
| Utility | De Watergroep |
How Tongeren compares
- Tap water in Tongeren is 8 % harder than the median of the 1091 cities we track in Belgium (31.6 °fH).
- By hardness it ranks 449 of 1091 in Belgium (1 = hardest); 59 % of these cities have softer water.
- In Limburg it is number 5 of 33 cities; the regional median is 16.5 °fH.
- Nearest city with clearly softer water: Riemst, 10 km away (13.7 °fH).
- Nearest city with clearly harder water: Glons, 6 km away (43.4 °fH).
Ranking of the hardest and softest water in Belgium →
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 Tongeren
| Brand | Setting for this water |
|---|---|
| Bosch | H05 |
| Miele | 19 °dH |
| AEG / Electrolux | 5 |
| Beko | 5th |
| Hoover | S3 |
| 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 Tongeren water hard or soft?
It is very hard: 339 mg/L as CaCO₃ (19.8 gpg, 19 °dH). The usual bands are soft < 60, moderately hard 60–120, hard 120–180 and very hard > 180 mg/L.
Is tap water in Tongeren safe to drink?
Hardness is not a health issue; it is about limescale, taste and appliances. Mains water must meet national drinking-water standards. Belgian suppliers report hardness in °f (French degrees); 1 °f = 10 mg/L CaCO₃.
How many grains per gallon is Tongeren water?
19.8 gpg, equal to 19 °dH, 33.9 °fH or 339 mg/L calcium carbonate.
What dishwasher salt setting should I use in Tongeren?
For 339 mg/L (19 °dH) check your manufacturer's table: maximum level (5–7).
Do I need a water softener in Tongeren?
Yes, unless you are only passing through: scale damages appliances within a few years.
Source
Source: VMM, Kwaliteit van het drinkwater per leveringsgebied 2024, bijlage 2 (mediane concentratie) (2024). Method: figure published by the water supplier. VMM, Kwaliteit van het drinkwater per leveringsgebied 2024, bijlage 2 (mediane concentratie) · Outdated figure? Tell us