When it comes to treating water in the backcountry, we generally consider water safe to drink when it’s free from pathogens—those pesky microorganisms that can cause illness, like bacteria, protozoa, and viruses. These little guys are the main concern because even a small number can lead to flu-like symptoms, which is not fun, especially on a short backpacking trip.
On the other hand, non-biological contaminants, while not very appealing, usually require a larger amount to cause harm, often from long-term exposure. For instance, if you frequently find yourself drinking from sources with pesticide runoff on your favorite trail, that’s something to keep in mind. However, most backcountry areas are relatively low-risk for these types of contaminants, and the small amounts you might encounter on a typical trip are generally not something to worry too much about.
That said, it’s a good idea to evaluate your own risk and include water collection in your trip planning.
If you’re planning to filter water from a non-alpine source, just remember that chemical contaminants are something to consider. Water purifiers can effectively remove particles as small as viruses, but chemicals are even smaller, which can be a challenge.
We often hear the question: can my water filter remove salt from drinking water, especially in brackish or saltwater areas? The quick answer is no. Salt is a molecule, and like other chemicals, it’s too small to be filtered out by backcountry purifiers like our MSR Guardian Systems.
Finally, always keep in mind that cross-contamination can occur in the backcountry. While purifying your water is a great step, it won’t protect you from viruses, bacteria, or protozoa that might be picked up on your hands, cooking utensils, or other surfaces that come into contact with your body.
Check out our blog post for more detailed information on this topic.