| How it works | Squeeze water through hollow fibers |
| Removes | Bacteria, protozoa, sediment |
| Strengths | Light, fast, cheap, popular |
| Care | Backflush; never let it freeze |
A squeeze filter is a lightweight hollow-fiber water filter you screw onto a soft flask or bottle and squeeze, forcing water through the element to remove bacteria, protozoa, and sediment. Compact, fast, and inexpensive, it is the most popular backpacking filter, though it needs regular backflushing and must be protected from freezing.
Filter formats
The most popular water filter type; for big groups a gravity filter scales better. For viruses, add a UV purifier or chemicals — part of overall water treatment.
Frequently asked questions
What is a squeeze water filter?
A squeeze filter is a small filter cartridge (usually hollow-fiber) that threads onto a soft, fillable bottle or flask. You scoop dirty water, attach the filter, and squeeze, pushing the water through the element so it comes out clean. It's the most popular backpacking filter for its light weight and simplicity.
Do squeeze filters remove viruses?
No — like most filters, hollow-fiber squeeze filters trap bacteria, protozoa (Giardia, Cryptosporidium), and sediment but not viruses, which are too small. Where viruses are a concern, add chemical treatment, use a UV purifier, or boil the water.
How do you care for a squeeze filter?
Backflush it regularly (force clean water backward through it) to restore flow as it clogs, pre-filter very dirty water to extend its life, and — crucially — never let it freeze, since ice can crack the hollow fibers and let pathogens through undetected. Keep it in your bag or jacket in cold weather.
Sources
- Water filters — American Hiking Society