Hi everyone,
I just got a Katadyn Hiker Pro water filtration system as a Father's Day gift. I've read the reviews and I'm really anxious to try it next month in Yosemite.

My question: I already know it wont filter viruses, but how common are viruses in the Yosemite waters? I know filtering from a flowing source is better than a standing one, but does anyone have any knowledge about if there are viruses? I know boiling and purifying tablets are always an option, but I really don't want to deal with the taste or the time it takes to boil. If viruses have been passed in Yosemite, then yeah of course, but how common is that?