I still have the collapsible plastic cup that my grandfather used to dip water from midstream in just about every stream in the Park that we fished together....but that was too many years ago than I will admit to....The two biggest factors since then has been the number of backpackers and pigs ...at time interchangeable...in the park. I now carry one of those collapsible filter bottles for emergencies....have yet to be sick but getting enough water to really satisfy a thrist is wome work....if overniting then I usually boil up enough water for a bottle in camp and one to take fishing.....to help with the "bleach" taste carry a couple of those single serving crystal light mixes...masks the taste pretty well.....and on those occasions where I am tempted it has been a small feeder rivlet off the side of the mountain.