Woft,

I guess it all depends on where you live or where you're travelling. Back in Pennsylvania I have never treated water because I've been drinking it out of mountain streams all my life and never had a problem. I still carry tablets there just in case but I never did use them.

Here in Brazil you can get sick from water in short order and they WON'T be able to cure you once you're rescued. I treat even the clearest running mountain stream water here. I have only once risked drinking untreated water here but it was a truly desperate situation. I have since never gone on even a day hike without the means to treat water.

Dysentary can strike over the course of a few hours, easily developing over night. Serious dehydration can set in the next day. Just the indignity of it all is enough for me to squeeze in a bottle of Potable Aqua. Mac