We were walking through the deep woods, navigating our way as best we could using a map and compass yet still not 100% sure of exactly where we were. Around 2:00pm we came upon a small, fast-moving stream. It looked clear and fresh, and we were thirsty from two days of backpacking.
We were thankful to find the stream; it was hot and our water supply was low. We debated about staying the night close by the stream, but we really needed to make a few more miles before nightfall so we decided to fill our water bottles and continue hiking along the remote and sparsely blazed trail.
Fresh, clear, and fast-moving water is a multi-sensory experience for the weary backpacker. The sound of water rushing over softball-sized rocks, the moist smell of cool air hovering above the stream, and the feel of water running trickling down your back as you squeeze it out of a soaked handkerchief brings a much needed infusion of energy and stamina back to your body.
But, for all of it’s benefits, you must be careful consuming it. Yes, even in the most remote areas of the country, waterborne illnesses can thrive and dangerously derail your time in the woods.
Many of these enter the water supply through fecal matter of people or animals. Others can enter through decaying animals that are in contact with the water source. Waterborne illnesses can be contracted by drinking contaminated water.
What’s Up Stream?
Many people mistakenly believe that fast-moving water is safe to drink, that bacteria and protozoa cannot exist in areas where the current is swift.
They are partially right. Given the choice between a fast-moving stream and slow,nearly stagnant water, I’d certainly choose to take my chances with the former. But that doesn’t mean that I’m not taking a risk.
What’s upstream from your vantage point?
Just beyond the bend maybe a wide watering hole used by all sorts of wild or domesticated animals that have no qualms about pooping in the same water that they drink. Or perhaps there is a half-rotted, diseased and decaying former member of the herd laying half in the watering hole.
Neither of these bode well for you.
It’s Best to Purify
In a pinch, facing dehydration, I’d drink the unpurified water. I’d try to get as close to the source of the water as possible, following it upstream to where it bubbles out of the ground or emerges from a rocks. I’d shy away from areas where there are lots of animal tracks and slow, stagnant-looking water. Cold water is also less likely to be infected with problematic parasites.
But it’s best to purify the water. Boiling or killing the parasites with iodine tablets or ultraviolet light works well. Filtering with a high-quality filter is another way to prevent intestinal discomfort.
Fast-moving water certainly decreases your chances of becoming infected with a waterborne pathogen, but it’s not a sure thing. When it doubt, purify.