There are plenty of ways to source "raw water" safely from mountain springs. It's not strictly a bad idea like raw milk or something. But if you're below the treeline, there's a 100% chance you'll be drinking animal shit.
There are people who drink raw milk without any ill effects but certainly it's not recommended!
I read somewhere, all water on Earth has some form of pollution from human sources (plastic, chemicals and other things). It was a study I think by the UN or NOAA.
Surface water, perhaps. But the water from aquifer fed artesian wells is generally hundreds or thousands of years old.
Don't worry, we have been polluting plenty of aquifers too!