I've seen it said in various places that prior to the introduction of tea and coffee, Europeans drank beer because unboiled water was dangerous due to various waterborne diseases but the beer-making process required water to be boiled therefore making it safe to drink. But I've also seen it said that people weren't constantly walking around in a drunken stupor because the beer (and wine) would be watered down. Surely the addition of non-boiled water would have been harmful?

So my questions are, was water in pre-industrial times as dangerous as it's often made out to be? Did people even know that water could make them sick? Did they drink water at all? And was alcohol really the standard beverage for everyone or just certain sectors of society?