msr flow

MSR AutoFlow Gravity Microfilter

Editor: Colorado Jake

Basic Description:

Collect, filter, and store your water in the backcountry with the quick and convenient MSR Autoflow Gravity Filter. This field-cleanable filter lets gravity do the work and cleans nearly two liters of water per minute. The four-liter reservoir holds enough wet stuff for your whole group, and the adapter end piece fits onto most standard water bottles and reservoirs.

Just the Facts:

Filter Material:
Hollow Fiber
1.75 L 1 min
protazoa, bacteria, particles
4 in 6 in
Gravity Flow:
Cartridge Life:
1500 L
Claimed Weight:
13.8 oz
Recommended Use:
backpacking, expeditions, basecamp
Manufacturer Warranty:
1 year


I finally broke down and made the switch to gravity water filtering. After years of being hunched over a small creek or lake getting eaten alive by bugs, getting my boots wet, or multiple trips back and forth. I was done with pumping. Now, I simply fill the 4 plus litter bag, walk back to camp, hang it, and effortlessly fill a equal size reservoir bag. You can get all your other projects done (if you’re really fast) like start a fire, cook dinner, or set up your tent. Then turn around and have a bountiful amount of water at your disposal.

The Autoflow is not only easy, but fast as well. It’s rated at 1.75 litters a min. Much faster then most pump filters on the market with a few exceptions. It’s also lighter then most pumps and that includes the extra large dirty water bag. I love this feature because you can bring access to water right into camp. I like to fill all of my water bottles, bladders, and then grab another full bag of dirty water to top everything off when needed.

I have been using this system on several multi-day backpacking trips and hunting trips this fall with little complaints. If you’re getting water out of a very swallow creek 1” or less. I have dug it out by hand and positioned rocks so I can fill the bag to full capacity. I have also used a cup and my hands to top off the bag when digging was not possible. I have filtered roughly 40 gallons through the filter without any slow down. I do back flush the filter each time I get home with warm water and white vinegar.

If you’re on the market for a new water filter, you won’t be disappointed by this gem. Fast, easy, and no more dreading the task of “filtering water”. Add a equal size reservoir bag and you’ll never have to remember to switch out bottles or bladders while getting camp ready. I only wish I would have made this switch many moons ago.

What they could do better:
Great as is!

MSR AutoFlow Gravity Microfilter Review
  • Functionality
  • Value
  • Ergonomics
  • Durability