Review: We Sawed a Sawyer Squeeze Water Filter in Half!

The Sawyer Squeeze water filter is one of the most popular water filter used by long-distance backpackers due to its ease of use and lightweight quality.

We wanted to get an INSIDE look at the Sawyer Squeeze to see how it really works, so we cut one open and took a close look with a microscope.


Read our series of Sawyer filter reviews:

Review: the new Sawyer Micro Squeeze

Sawyer Squeeze and Micro Squeeze Flow Rate Tests

Should I Carry the Sawyer Syringe?

Guthook filtering water into his water bottle using the Sawyer Squeeze.

Here is what we did...

We filled the Sawyer filter bag with some murky pond water.

Then we forced pond water through the Sawyer Squeeze into a water bottle.

Next we backflushed the Sawyer Squeeze with clean water.

Filtering pond water into a water bottle.

Backflushing the Sawyer Squeeze with clean water.

We disassembled the filter

We drilled out the locking points on the side of the filter.

Here is a view of the water intake side of the filter.  This is the side that the dirty water flows into.

Then we unscrewed the filter and removed the internal filter.

And here is a view of the outflow side of the filter.  This is where the clean water flows out of the filter.

Microscopic View

We bought an inexpensive microscope and hooked it up to a laptop to get a close up view of the filter.

Focusing the microscope on the outflow end of the filter.

The microscope reveals the small outflow tubes, where the clean water comes out.  A solid resin keeps water from flowing around the tubes.

Here, we set up a microscopic view of the long filter loops where the water flows into the filter.  Notice some dark particulate matter stuck to the sides of the loops.  Backflushing the filter removes these contaminants.

Final disassembly: saw in half!

To get a closer look at the long filter loops we removed the plastic housing that protects the filter from being damaged.

Now you can see the long filter loops (some tubes were damaged during the disassembly process).  Each long filter loop is secured to the outtake section of the filter, which is the portion covered by protective tissue in the photo.

The microscope reveals contaminants stuck to the side of the long filter loops.

Contaminated water comes into contact with the outside of the long, looped filter tubes. The pores on the side of the tubes are so tiny (0.1 microns or 0.0001 millimeters), that bacteria (0.2 microns to about 3 microns) and Giardia (7 to about 10 microns) can’t pass through the filter.  Water enters the wall of a tube through these small pores and comes out the end of the tube as purified water. Bacteria, Giardia, and debris are simply too big to pass through the pores. As the pores get clogged with debris and contaminants, the flow rate of the filter decreases.  To increase the flow rate of your filter, backflush the filter to remove the debris and contaminants.