When I first tried this filter and noticed how easy it was to drink, I initially wondered if it might be because it was less complete than other backcountry filters. It turns out it does, but not enough to matter in the real world.
The Epic Outdoor Water Filter Series removes 99.9999% of bacteria and 99.999% of protozoa. while Sawyer Squeeze and Lifestraws filters remove 99.99999% bacteria and 99,9999% of protozoa. This difference is minimal and they all meet NSF P231 standards for “microbiological purification”. While none of them filter viruses, they are all sufficiently capable of stopping common backcountry pathogens.
The other great thing about Epic is that it doesn’t just filter out protozoa and bacteria, unlike virtually all backcountry-specific filters. It also meets NSF water filter standards pesticides, chemical additives, heavy metals and pharmaceuticals (among other contaminants). Their filters use an activated carbon filter to achieve this, so the longer you soak it, the better it will work. But for backcountry pathogens, the hollow fiber membrane will remove everything when you drink from it.
Most backcountry water sources don’t contain contaminants common in tap water, but the fact that Epic water filters work for both means I confidently use my bottle too filtered as a daily water bottle.
It’s important to note here that Epic makes two bottle filters, called the Every day and the Outdoor. They look similar (although the Outdoor filter is colored orange so you can tell them apart), but the Everyday filter does not eliminate bacteria and protozoa. So if you need the filter for hiking or backpacking, make sure you get the outdoor one.