You're deep in the bowels of southern Utah's scenic Twentyfive Mile Wash. That's the good news. The bad news is that a flash flood just claimed your gear, including all means of disinfecting drinking water, and your car sits 15 sun-blasted miles away. To get there safely, you'll need fluids. But if you can't treat the water at your feet, you shouldn't drink it, right?
Maybe, maybe not. If you're only a few cool miles from the trailhead, don't imbibe. If, on the other hand, you're facing hot weather and big miles, you should drink up. Better to risk giardiasis or other illness than to collapse from dehydration far from help. Here are some emergency-only ways to minimize the hazards of swigging untreated H2O.
Drink from small tributaries rather than main streams. If possible, follow the tributary uphill to its source; a spring is your safest bet. Water running from a source in a high, uninhabited area is less likely to be contaminated.
Drink from the surface of a still, deep pool, and from the middle of the pool, as far from the bank as possible. Many harmful microbes settle below the water's surface.
Look for healthy, green plants around a pool. Avoid pools surrounded by barren ground in vegetated areas.
Dig a hole 6 to 12 inches deep at the outside bend of a stream. Water that seeps into the hole will be somewhat filtered by the surrounding soil and vegetation.
Drink from depressions in rocks or other places where rainwater has collected.
Catch as much rain as possible in pots and bottles; use tarps and tent flies as funnels.
Hold snow in your mouth until it melts, then swallow.
Gather the dew that collects on leaves, flowers, metal surfaces, and your tent before sunrise (see "The Wisdom Of Abo Dude," September 1999). Swipe the moisture from the surface with a T-shirt or bandanna, then wring it out into a cup.