Water hardness in Zaventem
31 °fH very hard
Tap water in Zaventem is very hard: 31 °fH (310 mg/L · 18.1 gpg · 17.4 °dH).
Source: VMM, Kwaliteit van het drinkwater per leveringsgebied 2024, bijlage 2 (mediane concentratie) (2024) · data checked 2026-10-19
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 reported 2024 figure is 309.9 mg/L CaCO₃ and no range is given for this supply area. 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 | 31 °fH |
|---|---|
| Utility | De Watergroep |
How Zaventem compares
- Tap water in Zaventem is close to the median of the 1091 cities we track in Belgium (31.6 °fH).
- By hardness it ranks 556 of 1091 in Belgium (1 = hardest); 49 % of these cities have softer water.
- In Vlaams-Brabant it is number 19 of 59 cities; the regional median is 26.6 °fH.
- Nearest city with clearly softer water: Zemst, 11 km away (18.4 °fH).
- Nearest city with clearly harder water: Bertem, 11 km away (39.3 °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 Zaventem
| Brand | Setting for this water |
|---|---|
| Bosch | H05 |
| Miele | 17 °dH |
| AEG / Electrolux | 4 |
| 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 Zaventem water hard or soft?
It is very hard: 310 mg/L as CaCO₃ (18.1 gpg, 17.4 °dH). The usual bands are soft < 60, moderately hard 60–120, hard 120–180 and very hard > 180 mg/L.
Is tap water in Zaventem 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 Zaventem water?
18.1 gpg, equal to 17.4 °dH, 31 °fH or 310 mg/L calcium carbonate.
What dishwasher salt setting should I use in Zaventem?
For 310 mg/L (17.4 °dH) check your manufacturer's table: maximum level (5–7).
Do I need a water softener in Zaventem?
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