In those time "beer" was drunk like water because it was safer than drinking the parasite and disease-infested water. Today we (mostly) all have water that is safe to drink.
This is apparently a bit of a myth. There was some knowledge of safe versus unsafe water. “Clean” water supplies weren’t uncommon and alcohol wasn’t a common substitute for clean drinking water.
That said, the beer was often weak and watered down so any mention of chronic use should be tempered by the strength of the drink.
