Water hardness in Brussels
37 °fH very hard
Tap water in Brussels is very hard: 37 °fH (370 mg/L · 21.6 gpg · 20.7 °dH).
Source: VIVAQUA, Qualité de l'eau dans votre rue (dureté moyenne, août 2026) (2026-08) · data checked 2026-10-22
Range across supply zones: 194–377 mg/L.
22 supply zones — hardness varies by neighbourhood; the figure above is the median.
Hardness by district / supply zone
| °fH | mg/L | ||
|---|---|---|---|
| Anderlecht (1070), réservoir Ixelles | 37.7 | 377 | very hard |
| Auderghem (1160), réservoir Rhode | 37 | 370 | very hard |
| Berchem-Sainte-Agathe (1082), réservoir Callois | 19.4 | 194 | very hard |
| Bruxelles (Pentagone) (1000), réservoir Rhode | 37 | 370 | very hard |
| Etterbeek (1040), réservoir Rhode | 37 | 370 | very hard |
| Evere (1140), réservoir Rhode | 37 | 370 | very hard |
| Forest (1190), réservoir Callois | 19.4 | 194 | very hard |
| Ganshoren (1083), réservoir Callois | 19.4 | 194 | very hard |
| Haren (1130), réservoir Rhode | 37 | 370 | very hard |
| Ixelles (1050), réservoir Rhode | 37 | 370 | very hard |
| Jette (1090), réservoir Boitsfort | 37.6 | 376 | very hard |
| Koekelberg (1081), réservoir Boitsfort | 37.6 | 376 | very hard |
| Laeken (1020), réservoir Boitsfort + Ixelles | 37.6 | 377 | very hard |
| Molenbeek-Saint-Jean (1080), réservoir Boitsfort + Ixelles | 37.6 | 377 | very hard |
| Neder-Over-Heembeek (1120), réservoir Rhode | 37 | 370 | very hard |
| Saint-Gilles (1060), réservoir Boitsfort | 37.6 | 376 | very hard |
| Saint-Josse-ten-Noode (1210), réservoir Boitsfort | 37.6 | 376 | very hard |
| Schaerbeek (1030), réservoir Boitsfort | 37.6 | 376 | very hard |
| Uccle (1180), réservoir Callois | 19.4 | 194 | very hard |
| Watermael-Boitsfort (1170), réservoir Rhode | 37 | 370 | very hard |
| Woluwe-Saint-Lambert (1200), réservoir Rhode | 37 | 370 | very hard |
| Woluwe-Saint-Pierre (1150), réservoir Rhode | 37 | 370 | very hard |
Brussels is supplied by VIVAQUA, which draws most of its water from groundwater, mainly from catchments in Wallonia, and treats Meuse river water at its Tailfer plant for the rest; only a small share comes from wells in the Sonian Forest. The 2026 figure is a median of 370.0 mg/L CaCO₃ across 22 supply zones, ranging from 194.0 to 377.0 mg/L, so it depends on the street. At this level limescale builds up quickly in kettles, boilers and washing machines, so descaling and a softener are worth considering.
Belgian suppliers report hardness in °f (French degrees); 1 °f = 10 mg/L CaCO₃.
Water data
| Total hardness | 37 °fH |
|---|---|
| Utility | VIVAQUA |
How Brussels compares
- Tap water in Brussels is 17 % harder than the median of the 1091 cities we track in Belgium (31.6 °fH).
- By hardness it ranks 312 of 1091 in Belgium (1 = hardest); 71 % of these cities have softer water.
- Nearest city with clearly softer water: Dilbeek, 6 km away (16.9 °fH).
- Nearest city with clearly harder water: Saintes, 21 km away (49.3 °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 Brussels
| Brand | Setting for this water |
|---|---|
| Bosch | H05 |
| Miele | 21 °dH |
| AEG / Electrolux | 5 |
| Beko | 6th |
| 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 Brussels water hard or soft?
It is very hard: 370 mg/L as CaCO₃ (21.6 gpg, 20.7 °dH). The usual bands are soft < 60, moderately hard 60–120, hard 120–180 and very hard > 180 mg/L.
Is tap water in Brussels 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 Brussels water?
21.6 gpg, equal to 20.7 °dH, 37 °fH or 370 mg/L calcium carbonate.
What dishwasher salt setting should I use in Brussels?
For 370 mg/L (20.7 °dH) check your manufacturer's table: maximum level (5–7).
Do I need a water softener in Brussels?
Yes, unless you are only passing through: scale damages appliances within a few years.
Source
Source: VIVAQUA, Qualité de l'eau dans votre rue (dureté moyenne, août 2026) (2026-08). Method: figure published by the water supplier. VIVAQUA, Qualité de l'eau dans votre rue (dureté moyenne, août 2026) · Outdated figure? Tell us