Sorry...I'm relatively new here...and I can't tell from the context; what's "drinking smart" mean exactly?
I wouldn't want to speak for Bob, but it's not a bad phrase. To me, it would just mean don't be paranoid when hiking in the Sierra.
In the National Parks, the water is likely good if you're semi-careful. Look at the map of the streams you cross -- if there's no trail or obvious camp sites above you, the water is very likely good. The closer you are to dense use -- and especially stock use -- the more quality degrades. Except in a very few cases, I have never treated any of the water I drink in Sequoia Kings. On the USFS areas -- and especially where there's cattle -- I might be more cautious. 3% to 6% of horses/mules carry giardia -- and that's thousands of cysts per poop. I would definitely treat or avoid in all cattle areas.
I think basically it's knowing the ultimate source of the water you drink and knowing who else might be upstream of you.
George