Are water-borne nasties only a problem in other countries?

I've been backpacking several times borrowing other people's equipment, but now I'm getting ready for a trip in the Adirondacks and need to get some more gear of my own. Is it true that viruses are primarily a problem in the water in other countries? What viruses are potentially problematic in the U.S., and what illness do they cause? Adina Syracuse, New York

A: For years, the conventional wisdom in the United States was that while bacteria and organisms such as the giardiasis protozoa were a concern for backpackers, viruses such as the norovirus and hepatitis were not. Today, while viruses remain what is probably a low risk, it can't be said that there is no risk of contracting one from drinking backwoods water. And viruses can be nasty things. The norovirus—which has ruined many a cruise-ship vacation in recent years—causes severe diarrhea and vomiting that can last several days. Hepatitis is even worse; hepatitis B can kill you, although the more common hepatitis A usually corrects itself on its own after a few weeks.

SweetWater Purifier

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So, what to do? Always filter water, of course. Beyond that, my policy is to consider its source. The closer I am to where the water got its start—a glacier, a snowfield, a spring—the less concerned I am about viruses. I don't think the Adirondacks area poses a particular risk, but its high usage by humans might warrant caution. If you are concerned, then it's prudent to treat the water with a virus-killing agent such as SweetWater Purifier ($9;, a chlorine-based agent that kills just about anything that wiggles... in your water, that is.

Otherwise, you might want to consider one of Katadyn's filtration pumps, albeit a little more costly and bulky, but able to deliver quick, potable water on the go. The 11-ounce Katadyn Hiker ($60; is a compact system that delivers about a liter a minute without too much effort—great if you're in a group or don't fancy the aftertaste of some of the chemical treatments.

Get more water-filtration advice in Outside's 2004 Buyer's Guide.

Filed To: Filters and Purifiers
Lead Photo: courtesy, MSR