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Reviews > Water Treatment > Filters > Sawyer S3 Select Water Purifier > Test Report by Kurt Papke

Sawyer S3 Water Purifier

Test Series by Kurt Papke

Initial Report October 9, 2021

Field Report January 4, 2022

Tester Information

Name: Kurt Papke
Age: 68
Gender: Male
Height: 6' 4" (193 cm)
Weight: 220 lb (100 kg)
Email address: kwpapke at gmail dot com
City, State, Country: Tucson, Arizona USA

My backpacking venues have included a combination of Minnesota hikes where I have lived most of my adult life, and Arizona trails, where I moved to take a new job about a dozen years ago.  I have always been a "comfort-weight" backpacker, never counting grams, but still keeping my pack as light as easily attained.  I have been a hammock camper for eight years, though I still sleep on the ground when I must.  Many of my hikes in Arizona have problematic water sources with high amounts of heavy metals from mining runoff, requiring me to be aware of which sources are treatable.

Initial Report

Product Information

Sawyer Products, Inc.
S3 Select Water Purifier
Year of manufacture
US $79.99
Manufacturer website
0.625 lbs (280 g)
Measured weight: 0.604 lbs (274 g)
Contaminants Removed
Heavy metals, viruses, bacteria, protozoa, chemicals, pesticides
Volume purified/fill
20 oz (591 ml)
8.5 x 14 x 3 in
Measured: 14.2 x 2.6 x 2.6 in (36 cm x 6.5 cm x 6.5 cm)
I'm not sure how Sawyer came up with 8.5 inch height in their specifications, because it doesn't fit with any measured dimensions
 400 uses = 62.5 gallons (237 L)

The Sawyer S3 is designed to remove the largest range of contaminants in Sawyer's product line.  It accomplishes this with a 2-stage process: (1) foam purifier using adsorption, and (2) a standard hollow fiber micro-tube filter.  In the first stage, the dirty water is passed through the foam purifier by squeezing the bottle in an alternating motion.  In the second stage, the water is forced out of the bottle through the hollow fibers.  Note that the latter filter is the Sawyer Micro Squeeze, which can be purchased as a separate product.  Components shipped with the system include:
  1. Red "gummy" feeling bottle containing the foam purifier.  Sawyer states the foam has natural anti-bacterial properties, so it may be stored wet.
  2. Micro Squeeze filter
  3. Cleaning plunger - used for backwashing the filter
  4. Cleaning coupling (blue in color) - alternative backwash using a customer-supplied bottle
  5. Two pages of documentation & usage instructions
  6. Not included: any kind of pouch or carrying bag for the filter components

Initial Inspection

The design and construction seem to be high quality - inspecting the components I didn't see any weak points in the design, nor any manufacturing flaws.  All the components fit together well, and the screw on/off fittings did not require any struggling to get them to connect or loosen.

The system has a fair amount of heft to it - this is not an ultralight system.  The bottle has a very soft rubber, or "gummy" feel.  The softness should make it easy to move the dirty water around in the foam purifier, but I wonder if it will be susceptible to punctures or tears from sharp objects.  The bottle is also tall and thin, making it easy to get my hands around it to squeeze the dirty water through the foam, but especially with the Micro Squeeze filter attached to the top it could be tippy.  That said, with the cap on it is a closed system so it's not like water will escape if it falls over.

First Impressions

The instructions call for passing an initial bottle of clean water through the system to remove any impurities from the foam purifier.  I followed the instructions, filling the bottle 1/2 way, squeezing with alternating hands 10 times, filling to the Max Fill line and repeating the 10 squeezes, then taking the filter off and rolling up the bottle to squeeze the water out of the foam without going through the hollow fiber filter.  After completing this I refilled the bottle and squeezed out the contents through the filter to see how much pressure was required.  Answer: not much pressure was required.  Also, it is very easy to do the alternating hand-squeeze to move the water through the foam.  I did notice that it was hard to see the Max Fill line, as it is embossed on the plastic bottle but not printed like the instructions are:

I also noticed it wasn't easy to fill the bottle through the small opening when the filter is unscrewed, especially with the screening in place.  It'll be interesting to see how well this works when filling in shallow streams, a common occurrence here in Arizona.

Good Things

  • Easy to use
  • Seems reasonably rugged
  • No need to store clean versus dirty side components in separate containers to avoid contamination
  • Fairly low effort required to process water through the system
  • Very complete purifying - if the specs are correct, this system should make just about any water drinkable
  • Purifier foam is naturally anti-bacterial, so I don't have to worry about drying the bottle after using

Areas for potential improvement

  • Fairly bulky and heavy for the amount of water treated.  The bulkiness is exacerbated by the fact that the bottle with foam purifier does not collapse completely for storage.
  • Low volume capacity.  I typically go though about 3 liters/quarts of water per day, which is about 5 bottles using this product.
  • Could be difficult to fill the bottle in shallow water sources.
  • Low longevity - the S1 filter does not remove heavy metals nor viruses, but has 4x the usage potential.
  • Difficult to see the Max Fill line

Field Report

Water Quality
Water Quantity
October 15-17, 2021
Chiricahua Mountains, Arizona
3 qt (3 l)
Sunny, lows around 40 F (4 C), highs around 70 F (21 C)
December 3-5, 2021
Aravaipa Canyon, Arizona
2 qt (2 l)
Sunny, lows around 40 F (4 C), highs around 65 F (18 C)

Chiricahua Mountains

3 day car camping and day hiking trip.  There was no potable water near our campsite, so I used a combination of water I brought with me and purified water from Turkey Creek.  The following collage shows the Sawyer S3 in action:

  1. Filling the bottle.  This was easier than I thought it might be - squeezing the bottle sucks the water right in.  That said, the water in the creek was deep enough that this was easily done without stirring up sediment.
  2. Screwing on the filter to the full bottle.  Only takes a second or two.
  3. "Massaging" the water through the foam purifier.  Easy peasy.
  4. Squeezing water through the Micro Squeeze - takes less effort than I thought it might.
  5. Rolling up the bottle to wring the water out of the foam filter.  This was required to get more than about 20 oz (590 ml) of water out with a single fill.
  6. Capping the Micro Squeeze filter to avoid remaining water draining out.

It was tough for me to get all the water out of the foam.  It might make sense to store water in the squeeze bottle to drink from directly or refill other bottles along the trail.  This would get some utility from the weighty bottle with soaked foam.

Aravaipa Canyon


As can be seen from the photo at left, there is no shortage of water in Aravaipa Canyon.  Our campsite was right along the creek, so for anything that required hot water I simply scooped up fresh unfiltered water from the creek and boiled it.  As a result I used only the 2 bottles that I carried in, and refilled them both once with the S3.

I did not backflush the filter before departing, and did not bring the syringe to do so with me.  I chose poorly.  From the outset it required enormous effort to get water through the filter.  I didn't time it, but I'd estimate it took me at least a half-hour to fill two water bottles.

One thing I learned during this experience is that it does not pay to squeeze really, really hard.  My hands got very tired, and it seemed like I was getting water leakage as I had a drip that was not coming from the filter output.

Note to self: before departing on all trips, backflush the filter at home.  If more than a couple of bottles of water will be treated, bring the backflush system along.

It would be helpful if Sawyer supplied a carrying bag for all the compnents that need to be carried out in the backcountry.  Bottle + filter + backflush gear = lots of parts that are easy to misplace or leave behind at the use site.

When I arrived home, I backwashed the filter and a lot of black gunk came out.  After several syringes of backwash, I put the filter back on the (full) bottle and the flow was back to normal.


Good things:

  1. The soft bottle seems pretty robust so far - no leaks, etc.
  2. Water purified with the system tastes good.
  3. Filling the bottle has been pretty easy so far.

Areas of possible improvement:

  1. Difficulties getting all the water out of the foam.
  2. Backflush required more quickly than I anticipated.
  3. Lots of pieces to pack and carry - a carrying bag would be nice.

Please stop back in two months for the Long Term Report where I'll have some real-life experience with the product.

Thanks to Sawyer and for organizing this effort

Read more reviews of Sawyer Products gear
Read more gear reviews by Kurt Papke

Reviews > Water Treatment > Filters > Sawyer S3 Select Water Purifier > Test Report by Kurt Papke

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