Water hardness in Aiseau
34.9 °fH very hard
Tap water in Aiseau is very hard: 34.9 °fH (349 mg/L · 20.4 gpg · 19.5 °dH).
Source: SPW, qualité de l'eau potable par zone de distribution, année civile 2025 (2025) · data checked 2026-10-19
Range across supply zones: 327–370 mg/L.
Aiseau, in Hainaut, is supplied by AIEM and SWDE. The SPW 2025 report gives 348.5 mg/L CaCO₃, with zone values from 327 to 370 mg/L. The water is very hard, and two suppliers mean it is worth checking which one serves your street.
Belgian suppliers report hardness in °f (French degrees); 1 °f = 10 mg/L CaCO₃.
Water data
| Total hardness | 34.9 °fH |
|---|---|
| Utility | AIEM, SWDE |
How Aiseau compares
- Tap water in Aiseau is 10 % harder than the median of the 1091 cities we track in Belgium (31.6 °fH).
- By hardness it ranks 404 of 1091 in Belgium (1 = hardest); 63 % of these cities have softer water.
- In Hainaut it is number 190 of 271 cities; the regional median is 38 °fH.
- Nearest city with clearly softer water: Franière, 11 km away (21.3 °fH).
- Nearest city with clearly harder water: Haine-Saint-Paul, 29 km away (46.4 °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 Aiseau
| Brand | Setting for this water |
|---|---|
| Bosch | H05 |
| Miele | 20 °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 Aiseau water hard or soft?
It is very hard: 349 mg/L as CaCO₃ (20.4 gpg, 19.5 °dH). The usual bands are soft < 60, moderately hard 60–120, hard 120–180 and very hard > 180 mg/L.
Is tap water in Aiseau 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 Aiseau water?
20.4 gpg, equal to 19.5 °dH, 34.9 °fH or 349 mg/L calcium carbonate.
What dishwasher salt setting should I use in Aiseau?
For 349 mg/L (19.5 °dH) check your manufacturer's table: maximum level (5–7).
Do I need a water softener in Aiseau?
Yes, unless you are only passing through: scale damages appliances within a few years.
Source
Source: SPW, qualité de l'eau potable par zone de distribution, année civile 2025 (2025). Method: figure published by the water supplier. SPW, qualité de l'eau potable par zone de distribution, année civile 2025 · Outdated figure? Tell us