Water hardness in Couillet
33.1 °fH very hard
Tap water in Couillet is very hard: 33.1 °fH (332 mg/L · 19.4 gpg · 18.6 °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: 315–370 mg/L.
Couillet, part of Charleroi in Hainaut, is supplied by SWDE. The SPW 2025 median is 331.5 mg/L CaCO₃, with zones from 315.0 to 370.0, which is very hard. Scale on heating elements builds quickly, so a descaling routine pays off.
Belgian suppliers report hardness in °f (French degrees); 1 °f = 10 mg/L CaCO₃.
Water data
| Total hardness | 33.1 °fH |
|---|---|
| Utility | SWDE |
How Couillet compares
- Tap water in Couillet is 5 % harder than the median of the 1091 cities we track in Belgium (31.6 °fH).
- By hardness it ranks 500 of 1091 in Belgium (1 = hardest); 54 % of these cities have softer water.
- In Hainaut it is number 223 of 271 cities; the regional median is 38 °fH.
- Nearest city with clearly softer water: Buvrinnes, 18 km away (21.6 °fH).
- Nearest city with clearly harder water: Haine-Saint-Paul, 20 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 Couillet
| Brand | Setting for this water |
|---|---|
| Bosch | H05 |
| Miele | 19 °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 Couillet water hard or soft?
It is very hard: 332 mg/L as CaCO₃ (19.4 gpg, 18.6 °dH). The usual bands are soft < 60, moderately hard 60–120, hard 120–180 and very hard > 180 mg/L.
Is tap water in Couillet 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 Couillet water?
19.4 gpg, equal to 18.6 °dH, 33.1 °fH or 332 mg/L calcium carbonate.
What dishwasher salt setting should I use in Couillet?
For 332 mg/L (18.6 °dH) check your manufacturer's table: maximum level (5–7).
Do I need a water softener in Couillet?
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