As I mentioned in my post about Aqua Mira drops, most solo ultralight hikers tend to go the chemical treatment route I mentioned earlier, or with a small filter. The Sawyer mini filter is a good and lightweight option for hikers who do want a potentially long lasting filter that can perform well. This filter will last for up to one hundred thousand gallons of water, and can filter out bacteria and protozoa. The flow rate on this filter is not great and can take a long time to filter even a liter of water, which is why it probably would not be optimal for group use. I would strongly recommend carrying the backflow pump while hiking, which serves to clear out the buildup inside of the filter and can increase the flow rate. If you are one to use a water bladder, this works great as it can be used inline to prevent having to filter the water all at once. This is a good filter for solo ultralight hikers who do not wish to have to periodically buy chemical treatment, though does not fare well for groups.