Does purify water before drinking really necessary in the backcountry? Do those high-priced pumps, chemical disinfectants, and elaborate filtration gadgets truly merit a place in the backpack?
"It's a huge debate," says Ryan Jordan, a biofilm engineer at Montana State University in Bozeman who has studied pollution in wilderness areas. The available scientific evidence, which is admittedly limited because of the scarcity of funding for testing wilderness water quality, confirms Derlet's findings.
The National Park System and the U.S. Forest Service urge backpackers not to drink untreated water, and it has become an accepted article of faith among wilderness travelers that a water cleanser is as indispensable as a tent, compass, and boots. Veteran backpackers like Jim Metropulos, who handles water quality issues for the Sierra Club in Sacramento, view water purification devices as an insurance policy that "provides a backup layer of security."
And yet, some doctors say that backcountry water is not safe to drink, even if it looks clear like glass. Defecating wildlife and encroaching hordes of campers who aren't environmentally savvy have spoiled the lakes, rivers, and streams of the pristine wilderness. "Infectious agents don't change the water's appearance. You can't taste, smell or see them," says Dr. Paul Auerbach, an emergency room physician at Stanford University in Palo Alto and author of the standard text "Field Guide to Wilderness Medicine." "All it takes is a few beavers upstream, and you're in big trouble."
You can safely drink the water by choosing it carefully. However, "If you have a question, then treat it," says Gregg Fauth, wilderness manager for Sequoia and Kings Canyon National Parks. If you have a hankering for fresh water and don't want to lug a pump or disinfectants that make the water unappetizing, drinking smart can minimize the risks of getting sick. The tips are:
Don't drink untreated water in places downstream from livestock pastures and large backpacker camps. "Humans and cattle are the worst offenders," Fauth says.
Water at higher elevations is safer because there's less risk of pollution by humans or wildlife. As water travels to lower elevations, it can pick up contaminants along the way.
Lake water, especially the top few inches, has fewer bacteria than running streams because of the rays of the sun act as a disinfectant. And big lakes are better than smaller, shallow lakes because there's more of a surface to sanitize.
Clean melted snow is less risky than ice from the surface of a lake or stream because hardy diarrhea-causing bacteria can survive for months on ice.
Deep well water is considered safe because the water is filtered when passing through the soil, which removes giardia cysts. Springs bubbling from the side of a mountain is generally safe too.
Avoid drinking untreated water from stagnant ponds or slow-moving streams.
Don't leave home without them: Alcohol hand gels, which are available in drug stores, are incredibly effective at inactivating bacteria on your hands. "Washing your hands," says Dr. Howard Backer, a water purification expert, "will prevent you from spreading bacteria to your fellow camper when you prepare the food."
— Linda Marsa
