Have We All Been Filtering Our Water Wrong the Whole Time?

On a recent backpacking trip, I stopped at a stream to filter water along with some other hikers. We were making hiker trash small talk (“Man, I’m starving. What’s your trail name? Have I told you about how gross my feet are yet?” etc. etc.) when I noticed one of my fellow hikers’ strange approach to water filtration.

First, he collected stream water in a smart water bottle. He then screwed a filter onto the bottle to purify and transfer its contents into a clean water bladder. Everything checks out so far. But then he poured that clean water back into the very same dirty water bottle. And then drank it!

My tender, former-chemistry-lab-tech heart quavered. Putting clean water back in a dirty container is far from best practice for water purification. Granted, the human immune system doesn’t care nearly as much about trace levels of contaminants as, say, a mass spectrometer, but still.

Filtering the water may have taken out any microscopic creepy-crawlies that had been living in it. However, contaminants could remain in the several milliliters’ worth of droplets clinging to the sides of the dirty water bottle. By pouring the clean water back into the same bottle without sterilizing it, my new friend had just reintroduced potential pathogens back into his drinking water.

And the ineffectual water filtration practices I’ve witnessed over the years don’t end there.

Continue learning more on water filtering techniques written by Kelly Floro here.