I think it would be a cool feature if the water that you pick up in a river biome would be drinkable right away.
Because I dont think it makes sense that you cant drink any water without poisoning yourself, in a world without any pollution and it would be like in the real world, where many new settlements started at rivers, because of the good water.
Maybe the hot spring water from BoP should be drinkable too, if it isnt already.