Guest - Not logged in 

Reviews > Water Treatment > Filters > Sawyer S1 Select Water Filter > Test Report by John Waters


INITIAL REPORT - October 11, 2021


NAME: John R. Waters
EMAIL: jrw at backpackgeartest dot org
AGE: 72
LOCATION: Canon City, Colorado USA
HEIGHT: 5' 7" (1.70 m)
WEIGHT: 175 lb (79.40 kg)

My backpacking began in 1999. I have hiked rainforests in Hawaii, Costa Rica, and Puerto Rico, glaciers in New Zealand and Iceland, 14ers in Colorado and Death Valley's deserts. I hike or snowshoe 6-8 miles (10 km-13 km) 2-3 times weekly in the Cooper Mountain range, with other day-long hikes on various other southwest and central Colorado trails. I frequently hike the mountains and deserts of Utah and Arizona as well. My daypack is 18 lb (8 kg); overnights weigh over 25 lb (11 kg). I'm aiming to reduce my weight load by 40% or more.



Manufacturer: Sawyer Products
Year of Manufacture: 2021
Manufacturer's Website:
Listed Height: 8.5 in (21.6 cm)
Listed Width: 14 in (35.6 cm)
Listed Length: 3 in (7.6 cm)
Listed Filter Weight: 0.625 oz (17.7 g)


I received the Sawyer S1 Water Filter the other day and I am looking forward to using it on upcoming treks. One will be in a few weeks in Utah in the areas around St. George.

So, this Initial Report is an overview of the product based on what was received, the specifications of the product and some topics to go over before I put this into field use. After several weeks of actual field use, the Mid and Final reports will review the pros and cons of real field results.

Meanwhile, this is what I received from Sawyer.

The packaging received was the standard retail hard plastic hanger case that has most of the information about the S1, including general specification and even basic use instruction without opening the case (a great idea). Inside is a detailed instruction sheet and a cleaner plunger.

The bottle included with the kit contains a non-replaceable foam filter/purifier inside (see photo). The bottle is green and squishy flexible (see photo) and there is a reason for that I'll explain later. Use instructions are etched on the bottle. The filter bottle output is 20 ounces (591 ml) and the bottle itself without the MicroSqueeze filter on top, is 10.5 inches (26.7 cm) high and 2.5 inches (6.35 cm) square and, when empty and new, weighs in at 0.5 lbs (227g).
Squishy Bottle
Micro Squeeze w/Top

The MicroSqueeze filter that attaches to the top is 4.1 inches (10.4 cm) high and 1.25 inches (3.18 cm) in diameter and weighs 2 oz (66.7 g) when new. This filter screws onto the top of the bottle after the bottle is filled and is specified at having 1,600 uses. It is from the opening at the top of this filter that I would drink or fill another vessel to drink from.

Although the bottle is quite flexible, there are warnings not to compress the bottle for packing to avoid damaging the inside black filter. The foam filter in the bottle is not a charcoal filter.

There is a well-done FAQ on the Sawyer website. I would like to point out a few of the FAQ answers here that are not mentioned on the packaging or on the included instructions.

"Taste: The Sawyer filter removes taste that comes from bacteria, dirt, and green matter. Taste can be masked by using flavor additives like Gatorade or crystal light (sic) (filter needs to be cleaned immediately after using them).

Chemicals: The Sawyer filter does NOT remove iron, sulfur, other chemicals, or simple compounds.
Heavy Metals: The Sawyer filters are not made with charcoal.

Will the filter/purifier remove chemicals, pesticides or heavy metals like arsenic?

Will the filter/purifier remove salt?

Why is the bottle squishy? (I said I would explain.)
When the bottle is filled with water to be processed, it needs to be squeezed at the top and bottom at least 10 times to move the water up and down through the interior black filter when half full and another 10 times after filling to the top line (but not too roughly).

How long does the filter/purifier last?
Since the filters and purifiers can continuously be backwashed and re-used, they have an extremely long life. The filter/purifier membrane may never need to be replaced, however when the flow rate slows or the filter clogs, simply backwash the unit with the provided backwashing device to clear out the pores."

There is a very detailed laboratory test results PDF for the S1 on the Sawyer website, as well.


Sawyer has Tips and Tricks for using the S1 Select Water Filter on their website which I (to make it easier for readers) list below:


1. Do not squeeze the pouch (or "squishly" botttle) too hard or wring the pouch.

2. Backwash the filter more often and with more force. Bring the light weight cleaning plunger on trips, especially if it is a multi-day trip. It is important that the first backwash is strong so that it cleans out all of the fibers rather than creating paths of least resistance. With turbid or muddy water, after backwashing push water forwards through the filter with the cleaning plunger to help loosen up any dirt that could be trapped between the fibers or still inside the filter casing, then repeat backwashing until water flows through clear.

3. Do not over-tighten the filter on the pouch. Over-tightening can cause the o-rings to embed into the threads or lodge into the opening of the pouch. If the o-ring is out of place the filter may not have a tight seal and water could leak out of the bottom of the filter.

4. If the filter is slow or plugged, try backwashing rigorously with hot water (no hotter than 140F/60C). It may need to be repeated several times to unclog the filter. If this does not return the flow to like new, the filter may have a calcium buildup in the fibers. Soak in vinegar for 30 minutes followed by rigorous backwashing with hot water (no hotter than 140F/60C). Repeat until the flow returns to normal. It may take several times to get it all the way clean again.

5. Do not freeze the filter. The filter is safe from freezing temperatures if it has never been used. However after the fibers are wet there is no definitive way to tell if a filter has been damaged due to freezing. Sawyer recommends replacing the filter if it is suspected that it has been frozen. If in freezing temperatures, we recommend that the filter be stored in a pocket or close to your person so that body heat can prevent freezing.

6. With all new technology, it takes time to learn how to best use it. Until the perfect balance of force and cleaning is learned, we recommend bringing a backup pouch on your trip.

7. Do not over-chlorinate when sanitizing the filter it will harm the fibers. One pouch capful of bleach to a pouch of water is all that is needed.

Instructions for regular care as well as long term storage are printed directly on the squeeze pouches. For instructional videos, FAQs, and the latest information and updates always check out


So, now this is going to be put into my backpack and put to use in a few weeks in the Utah mountains in November. One last note. This does not remove arsenic. So if there are streams with run-off from mining, I will have to be aware.

Thank you for reading my Initial Report on the Sawyer S1 Select Water Filter. Please return mid-December 2021 to see how I was able to use the S1.

John R. Waters

This report was created with the Report Writer Version 1.5 Copyright 2021. All rights reserved.

Read more reviews of Sawyer Products gear
Read more gear reviews by John Waters

Reviews > Water Treatment > Filters > Sawyer S1 Select Water Filter > Test Report by John Waters

Product tested and reviewed in each Formal Test Report has been provided free of charge by the manufacturer to Upon completion of the Test Series the writer is permitted to keep the product. Owner Reviews are based on product owned by the reviewer personally unless otherwise noted.

All material on this site is the exclusive property of
BackpackGearTest software copyright David Anderson