Bob, I should have started a new thread on this subject so that it would be easier access for everyone. Would you mind posting your link for the MR water sources again? Thanks!

Sure, here: reliable water on the Mountaineer's Route   Pictures here.

For completeness, reliable water on the main Mt. Whitney Trail   Pictures here.

And, as I have mentioned, I don't treat water from any of these sources. But I understand human nature, and am not offended if I see others doing it.

Thanks to Bob R's great research, I quit taking my filter up the mountain a few years ago. I freely savor some of the best water on the planet and in 30 years have never suffered a problem with unfiltered Whitney water. However, as Bob R has said, he drinks smart. The Trail Camp pond during the middle of summer and later is something I steer clear of, preferring the inlet stream (number 11 on Bob R's list).

It may not be considered a reliable source but I have seen Bob R. drink water from a small basin in the top of a boulder in the talus area between UBSL and the waterfall below Iceberg Lake. Bob walked right over to it as if he may have done this somewhat routinely.
Bob, sorry, I hope I haven't let out one of your secret water sources.
-Rick

Bob,

The last reliable water source on the main trail is at the switch back #23, how many liters of water do you recommend one to carry for the rest of the trail and back?

gatormom, that depends! This was last discussed on http://www.whitneyportalstore.com/cgi-bin/ubb/ultimatebb.cgi?ubb=get_topic;f=1;t=002139

But, to give you a recent data point, last Sunday I filled up a 1 liter canteen and a 0.5 liter canteen at that spring by switchback #23. I left the 0.5 liter canteen at Trail Crest and continued on to the summit. I kept drinking out of the 1 liter canteen and topping off with snow. When I got back to Trail Crest, I emptied out what was left in my 1 liter canteen, and picked up the 0.5 liter full one. I drank half of it, and gave the remaining half, a little later, to a lady who had run out. Got back to switchback #23 and it was all downhill from there. (No pun intended!)

But I know how to husband my water. Others may want more security. That is my reason for suggesting in that thread to carry 3 liters up from Trail Camp (or the spring), leaving 1 at Trail Crest for the return.

Rick, I'm sure I checked for "marmot souvenirs" first!

Bob..I just read your article/paper on Giardia and I was really, really impressed. What an excellent article..one I think all Western hikers could benefit from. I'll probably bring my filter out for our day hike up Half-Dome perhaps..but it is staying in the car for our trip up Whitney..

For those interested..Bob's article can be read here..it is very enlightening..

http://www.yosemite.org/naturenotes/Giardia.htm

Now if we could get you to come visit us out here on the east coast and do a water analysis of the Smoky Mountains/Blue Ridge/Appalachians...hehe...I'd like to know how the water around here fares!

Thanks for the article..you saved me a half a pound of "useless" weight on my climb..!

BeachAV8R

Thanks, BeachAV8R. But I bet you have to be a lot more careful with your water, than the Sierra's.

There are quite a few web sites that have posted the paper, and quite a few of them have an older version. The Yosemite Association's is one of the latter. For the latest version see, for example, http://lomaprieta.sierraclub.org/pcs/articles/giardia.asp

Just wanted to add my experience with drinking the water. I took the advice not to bother filtering. I drank from the switchbacks, and then from the output from Mirror Lake on the way down - that looked a little funky but it was fast flowing waterfall and I was out of water. Anyway i got diarrhea just once 10 days later - I'm pretty sure it was the water, even though it sounds like it wasn't giardia from bob's paper. But pretty much everything I ate on the trip was packaged or made beforehand so I don't see how else I would have gotten sick.

Hi Beach,

I did Half-Dome back in June. I didn't treat the water. Tanked up twice from the Merced river. No ill effects.

Rafael...