Exactly...
This debate isn't even really about filtering mountain water but it's more about Whitney Zone water.
I think this comment is very important because 1. there are no pack animals on the Main Trail 2. there are not herds of deer, either (both candidates for gastrointestinal buggers)
On the other hand, the idea of drinking the Yosemite water below 8K gives me the chills....ever notice the "apples" on some of the trails....or the hordes of deer in the meadows at night or morning. To each his own (I could care less what other people do regarding their health, as long as it is not contagious), but the odds definitely are in favor of picking up something with abundant carriers around the water (example: the trail next to Tuolumne River/Falls is rank with pack animal droppings...next to the water...)
you need to get our earlier in the season. On our return hike up to TM, we actually met the first horses that crossed Cathedral Pass last summer (trail crew cutting trees for the season), and they almost didn't make it. Deer and bear were out in force, though.
Giardia needs to be re-introduced each year. It doesn't survive freezing temps. So there's some thought behind my madness to drink unfiltered water down there last year. I was the only one who got sick, and it isn't even certain that it came from that area, as the incubation time is several weeks. Maybe it was the tap water at Reds. Who knows? Yosemite just happens to be the place I was in 3 weeks before it started to get ugly and I can think of one place that wasn't as safe a water source as I thought it was when I used it.
