Because you never know what’s in the water, it makes sense to always protect yourself with a quality water system. A pristine stream may be safe one day and contaminated the next. It all depends upon what’s happening upstream. Microorganisms generally come from human and animal waste and are spread by rain and run-off. The EPA reports that 90% of the world’s fresh water supply is contaminated.
“We highly recommend treating water from every source in the backcountry. You don’t know what’s upstream – not just people but animals – and you can get infected.”