Quick answer: for most backpackers, a squeeze filter such as the Sawyer Squeeze or Katadyn BeFree is the best mix of low weight, speed and price. Groups and base campers do better with a gravity filter like the Platypus GravityWorks. Travel to places with viral risk needs a purifier (such as the Grayl GeoPress) or a filter plus chemical treatment.
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Filter or purifier?
Most backcountry water filters remove bacteria (like E. coli) and protozoa (like Giardia and Cryptosporidium), which are the main concerns in North America and Europe. They don’t reliably remove viruses, which are rare in remote wilderness water but more of a concern in places with poor sanitation. Purifiers, UV pens and chemical treatments deal with viruses.
Types of backpacking water filters
| Type | Pros | Cons | Best for |
|---|---|---|---|
| Squeeze filter | Light, cheap, fast | Pouches can split; squeezing for groups is slow | Solo hikers, thru-hikers |
| Soft-flask filter | Very light, drink directly | Low capacity | Trail runners, fast hikers |
| Gravity filter | Hands-free, great for groups | Needs something to hang it from; bulkier | Groups, base camps |
| Pump filter | Works from shallow pools | Heavier, slower, more parts | Low or murky water sources |
| Purifier bottle | Removes viruses too | Heavier, smaller capacity | International travel |
| Chemical tablets | Ultralight back-up, kill viruses | Wait times, taste | Back-up or emergency |
What to look for
- Pore size: 0.1–0.2 micron hollow-fibre filters remove bacteria and protozoa.
- Flow rate: faster filters save a lot of time at water stops.
- Field maintenance: back-flushing or shaking restores flow.
- Freezing: a frozen hollow-fibre filter can be damaged; keep it in your sleeping bag in cold weather.
- Compatibility: some filters screw onto standard plastic bottles (28 mm thread).
Our picks
| 1 | Top PickSawyer SqueezeBest all-round backpacking filter | |
| 2 | Katadyn BeFreeFastest flow and lightest set-up | |
| 3 | Platypus GravityWorks 4LGroups and base camps | |
| 4 | LifeStraw Peak SqueezeBudget and durability | |
| 5 | Grayl GeoPress PurifierInternational travel |
Notes on our picks
- Sawyer Squeeze: The classic: light, long-lasting and fits standard bottles. Back-flush it regularly to keep flow high.
- Katadyn BeFree: Very fast filter on a soft flask; easy to clean by shaking. The flask is less durable than a hard bottle.
- Platypus GravityWorks 4L: Fill, hang and let gravity do the work. Excellent for two or more people.
- LifeStraw Peak Squeeze: A tough squeeze filter with a sturdy pouch; good value.
- Grayl GeoPress Purifier: Removes viruses, bacteria and protozoa in one press. Heavier, but simple and fast.
Water tips on the trail
- Collect from flowing water where possible, upstream of trails and camps.
- Pre-filter silty water through a bandana to protect your filter.
- Keep “dirty” and “clean” containers separate.
- Carry a few purification tablets as a back-up.
Frequently asked questions
Do I need to filter water from mountain streams?
Yes. Even clear streams can carry Giardia and bacteria from animals.
How long do backpacking filters last?
Hollow-fibre filters like the Sawyer Squeeze are rated for very large volumes if cleaned regularly; replace when flow cannot be restored or if the filter freezes.
Is boiling better than filtering?
Boiling kills all pathogens but uses fuel and time. Most hikers filter and keep boiling as a back-up.
Keep reading
Hi, I am Emam Hasan — founder and editor of BrokeMountain. I oversee this blog’s hiking, camping and outdoor gear guides, making sure every article is well-researched, accurate and genuinely helpful for your time on the trail. Enjoy it!
