
Access to clean drinking water is never a guarantee in the wilderness, which is why a good filter is essential on your outdoor adventure. To remove bacteria, parasites, and other contaminants, the best backpacking water filters have a micron size of 0.4 or less, and they come in a range of styles, from gravity filters to straws.
The effectiveness of a portable water filter depends on the size of the pores in the filter itself, which is measured in microns. One micron is equivalent to 1/1,000 of a millimeter, and filters with smaller micron measurements will be able to filter out smaller particulates. Pores with a micron size of 1 or less can filter parasitic larvae, eggs, and protozoa, while a micron size of 0.4 or less will remove bacteria.