In Venice and other towns in Italy, we have been told that for hygienic reasons, customers cannot be served acqua dell rubinetto – tap water.

Yet, at bars in those same towns, tap water can be served with a cup of coffee.
And on the water buses in Venice, the city council has put up signs – see my photo – encouraging people to DRINK TAP WATER.
IF tap water was to be served in restaurants, the greedy owners might be deprived of 1 to 4 Euros per bottle of the only kind of water they are prepared to serve.