I get asked about water purification every week at the store. Here is what I actually use and why.
1. Squeeze filter (Sawyer Squeeze)
My default for 95 percent of trips. Threads on a Smartwater bottle. Push-squeeze, filtered water comes out. 0.1 micron filter catches bacteria and protozoa. Doesn't catch viruses, but viruses aren't really a concern in North America backcountry.
Downsides: backflush weekly to keep flow rate up. Don't freeze it, ever. The membrane cracks and you won't know until you get giardia.
2. UV (SteriPEN Ultra)
For when I'm on a glacial stream or in the mountains where the water is already clear and I want speed. 90 seconds per liter. Kills bacteria, viruses, and protozoa. Rechargeable.
Downsides: doesn't filter particles. Cloudy water needs pre-filtering. Battery-dependent, which stinks in deep cold.
3. Chemical (Aquamira drops)
Emergency backup. I carry a tiny bottle on every trip and hope to never use it. Two-part drops, 30-minute wait, and you have drinkable water. No moving parts to break.
Downsides: the wait. And the taste is meh.
What I don't carry
Boil. Works in a tea kettle at home. Not efficient on trail. Uses too much fuel.
Pump filter. Heavy. Slow. No faster than a squeeze once you factor in all the assembly. And more parts to break.
Pre-filter everything
If the water is cloudy, scoop through a bandana first. Takes 10 seconds. Extends the life of any filter you run it through next.
Ask me at the store if you want to try the Sawyer on the demo sink. We keep one set up.
