Treat backcountry water. The method that stays in the pack is the one you will actually use when you are tired.
On the 2025 PCT, 79% of hikers always treated water. 5.9% still got sick. On the CDT, 80.9% always treated; 12.8% reported getting sick. Filters are not a personality. They are a habit.
- Squeeze method. Dirty bag on the inlet. Clean bottle or bladder on the outlet. Squeeze with even pressure. Do not crank so hard you blow a seam.
- Gravity. Hang the dirty bag, put the filter in line, and walk away. An open-end dirty bag makes filling from shallow sources less miserable.
- Maintenance. Backflush when flow slows, using the syringe that ships with a hollow-fiber squeeze filter.
- Backup. Chlorine dioxide tablets or drops cover a failed filter. Boiling works: a rolling boil for 1 minute, 3 minutes above about 6,500 ft.
Know the next water. Recent comments from hikers ahead of you beat a two-year-old guidebook. In desert stretches, long carries are the plan — not a surprise.
The CDC: a typical 0.3-micron-class filter does not remove viruses. Chemical treatment or a rolling boil covers what the filter does not.
CDC — water treatment for hiking, camping, and traveling →The 2025 ATC survey: 19.86% of AT hikers wished they had planned water better. Carry capacity of at least two liters is the Conservancy’s baseline. How much you fill depends on the next source, not on habit.
ATC 2025 — what hikers wish they knew →