Forgot to include links to more links - most new research info on Sierra Nevada water quality is coming out of UC Davis, and supports what Bob Rockwell has been writing about the high country wild areas being safe, and the popular lower areas not so much. The risk is correlated with the amount people, and definitely correlated to stock use. No surprise. Dip and sip wisely.
Summary from Mono Co SAR Nature Notes - Water Quality Links 
