>It's probably the last place on earth that one can still drink pure water right out of a lake
Dramatic much? I've done this many times from lakes in the Rocky Mountains in the US. I'm sure there are countless other places where it can be done as well.
There are certainly clear, cold lakes in the Rockies. However, I really wouldn't advise just drinking out of them without filtering or other water treatment. Yeah, you'll probably be fine but there's definitely Giardia and Cryptosporidium in a lot of water sources that look perfectly clean.
http://ucdmc.ucdavis.edu/publish/news/newsroom/1789 is the only significant study that I'm aware of. My interpretation is that risks are substantially over stated for true "back country" sources in the Sierras and likely most other places where you would find drainage areas without significant human impact. I still filter water almost all of the time but I worry less when I can't for one reason or another.
I don't really disagree. I expect that, as a practical matter, it's pretty safe to just drink water in a lot of remote places. That said, I also filter or use iodine even if I don't worry about medical facility cross-contamination procedures a lot of the time :-) It's not a lot of trouble and the consequences of getting an infection are unpleasant.
Look. I have no idea personally. However, conventional wisdom is that it's prudent to treat water. If I were dehydrated and had no treatment options, I'd certainly take my chances and drink apparently clear, clean water. (And have on occasion.) But I wouldn't just set off on the assumption it wasn't necessary either.
Yeah, I grew up in New Zealand, and I kept hearing how we had the "most beautiful country in the world", so somehow I got the impression that no other country had beautiful nature like ours. That's completely untrue. There are countless places in the US, Canada, Europe, and Asia where the nature is absolutely pristine and stunning. Canada actually feels very similar to New Zealand in some places.
Most lakes and streams at high altitude in the Sierras, Cascades, Rockies, etc are safe to drink. Once you're above the tree line you don't have to be worried about giardia because few animals live that high up.
Dramatic much? I've done this many times from lakes in the Rocky Mountains in the US. I'm sure there are countless other places where it can be done as well.