Good Day, Most people do not do this anywhere in the Sierra's. My Dad has been an avid hiker and backpacker while I grew up, and I do quite a bit lately in my early 50's. He was a "dip and sip" guy as I grew up (I was too). But only from head springs or vast snow melt from steep clif sides. Wild game can pass giardia too. He had no issues until one bad experience with giardia which does not go away without treatment. Although it is great to chug ice cold water from a spring, I feel it is not worth the risk. Giardia is probably the most benign organism which you might contract. Treat, filter, or boil. Unless an emergency, then go for it. Just my 2 cents woth of advice.