Belgium having the same quality on the map as the Netherlands shows me that the source of then information is wrong or the scale isn’t nuanced enough to be of any use to me. Belgian tap water should, on any scale, be at least a category lower than Dutch tap water.
Belgian tap water is horrible compared to Dutch water. Source: I lived in Brussels for 5 years. Could be just the brusselonian water, but there is a reason that bottles water is a thing that everyone buys in Belgium and practically nobody buys in the Netherlands.
You are right, I should have specified that tap water quality doesn't include the taste of it.
Apart from that Belgium tap water is perfectly safe to drink! I don't know specifics about the tap water in Belgium but something as simple as a carbon filter removes Chlorine and a lot of the bad taste!
I have been to Belgium before, to Brussels and Leuven, as far as I remember I liked the tap water better in Leuven, but that's just anecdotal. What I want to say with that is that tap water usually varies from area to area.
Taste/appearance and safety are not really the same thing. Many places have water that people find unpleasant due to mineral content or other factors, but which is safe to drink.
Belgian tap water is horrible compared to Dutch water. Source: I lived in Brussels for 5 years. Could be just the brusselonian water, but there is a reason that bottles water is a thing that everyone buys in Belgium and practically nobody buys in the Netherlands.