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The Sawyer S2 Foam Filter is a two-step purification system that filters out everything from bacteria to viruses to chemical contaminants. It features a Sawyer Micro Squeeze that attaches to a squeezable rubber-like bottle filled with foam that utilizes technology that removes pesticides, chemicals, and viruses. The Micro Squeeze filter is the second step. When drinking from the bottle or squeezing it into another vessel, it removes bacteria, protozoa (including Giardia and Cryptosporidium), and most debris.
While on a two-week trip to Mexico, it kept us safe from water-borne pathogens found in our drinking water. We don't like how bulky and heavy this system is, nor do we enjoy the black particulates that come out in the final filtration step from the foam inside (especially after 80+ uses). While the bottle seems to be sturdy, it has a lot of parts that can be lost easily. We found the Grayl Ultralight Water Purifier is the more straightforward to use option that isn't as bulky. While the Grayl doesn't come with an additional filter that can be used on its own to filter out bacteria and protozoan, it 's better to carry, at a similar price. While the Sawyer S2 certainly is versatile with a niche use, it's certainly not our favorite or one we'd recommend readily.
Our Analysis and Test Results
The Sawyer S2 is ideal for international travel. It protects from viruses but does deposit debris from the foam into your drinking water. It's not our favorite system, but it may fit your needs.
Performance Comparison
The S2 Squeeze is a purifier that gets rid of pathogens from bacteria to viruses. A perfect option for international travel.
Credit: Amber King
Water Quality
This filtration system utilizes a two-step filtration process that removes everything from bacteria to viruses to chemicals and pesticides. It uses a squeeze bottle filled with foam and absorption technology. When the water goes through this process, it removes pesticides, chemicals, and viruses. On the top of the bottle, the Sawyer Micro Squeeze filter attaches with a 0.1 absolute micron size. This step removes bacteria and protozoans like Giardia and Cryptosporidium.
We used the S2 to filter water from the tap at our BnB in Mexico City.
Credit: Ian McEleney
The quality of water was subpar, especially after a few uses. While it has a disclaimer that some of the foam material may come out in your water and is safe, we were a little put-off. The water turns a disconcerting blueish-purple color. We also researched online and found this to be a norm with this filter, with other users having the same problem.
Overall, water quality is good because it removes viruses, but because of this color change and the particles, it wasn't our favorite.
A look at some of the black particulates that were filtered out of both systems after many uses.
Credit: Amber King
Durability & Maintenance
The construction of the bottle is great, being flexible, so it's not prone to breaking. The material is also very sturdy and will not puncture. While this is great, we lamented all the little parts that can easily be lost while collecting water. The seal itself seems to be flimsy and don't trust that it will last the life of this system which is about 800 uses or 500 liters of water.
The Sawyer S2 comes with a bottle with foam enclosed, the Sawyer micro squeeze filter and a cleaning plunger.
Credit: Jessica Haist
Treatment Time
Depending on how you attain your water, treatment time varies. You can either drink from the bottle or squeeze it the water into another bottle. When drinking from the bottle, you can get water instantly.
You can drink directly from the filter, but it's slightly awkward and we prefer to fill another bottle to drink from. Here reviewer Jessica Haist poses in downtown Mexico City.
Credit: Ian McEleney
In our timed tests, we managed to squeeze a liter's worth of water in about 2 minutes and 28 seconds. As a result, this bottle is best used for instant use simply because squeezing is tedious, difficult and takes a lot of time. Also, the bottle isn't a liter in size, so you have to do a couple of squeeze preps to get just a liter.
If you have a lot of water to fill, you'll need to dedicate some time out of your day to do it with the S2. The bottle is supposed to treat 20oz but it's hard to get all that water squeezed from the foam, and if you do, you're sure to get foam particulate in your water.
Weight & Packability
This system is not lightweight or particularly packable. Once you use the filter once, it holds water which can add many ounces of weight. With a dry weight, it's about 9.75 ounces, but once used, it'll be about 13 ounces of extra weight. In comparison to other filtrations systems, this is heavy, even though it does include the bottle. We would never use this filter for backpacking purposes simply because of its bulky and less packable design but is a decent option for international travel while next to the pool or in your favorite Air BnB.
The dry weight of this set-up.
Credit: Amber King
Ease of Set-Up
The S2 is relatively straight-forward to use, but does require a couple of steps. First, you must collect the water. Given the bottle's larger and bulkier design, it is not fit for shallow or hard-to-reach water sources that would be out of arms' reach. The best place to fill this bottle is under a continuous stream like a small waterfall or trickle. Submersion also works. The flexibility of the bottle allows you to jam it under the mouth of a sink.
Be sure to remove the plastic collar and filter inside (which we forgot often) to avoid losing these important pieces before filtering.
The Sawyer S2 Foam Filter is a great choice for traveling when drinking the water out of the tap is not safe. It's flexible bottle makes it easy to fill from all kinds of sinks.
Credit: Ian McEleney
Filling the bottle during the first few uses is a bit annoying. We found that we had to very slowly fill it under the sink so the water wouldn't overflow. Filling took about five minutes the first time, which was not satisfactory. However, after a few more fill-ups and the foam was completely saturated, it is much easier to fill, taking just a few seconds. It's also important NOT to fill past the max line. There is space between this max line and the neck of the bottle that will escape filtration if you do, leaving you susceptible to viruses.
A look at the set-up when put together. The filter on the top can be used as a straw filter or with other bottles but does not filter out viruses.
Credit: Amber King
Once it's filled, place the plastic collar and filter back on and inside the neck of the bottle. Then affix the secondary filtration system on top. In general, we could this to be annoying as the bottle bends under the force of twisting on the filter, but we got the hang of it after a while.
The collar on the top is a little flimsy and we worry about losing it and the plastic filter inside the neck of the bottle when filling.
Credit: Amber King
Overall, set-up is somewhat straightforward, but you need to be patient in the first steps of use. Be sure not to lose small parts while collecting water.
Ease of Filtration
Once you've set-up the filter, the rest is pretty simple. Squeeze the water in the bottle back and forth, top to bottom for about 10 seconds, using a little muscle. Then you can drink directly from the bottle or squeeze it into a secondary storage vessel. Drinking straight from the bottle is a little slow, but not slower than other filters out there. Sadly, it's hard to squeeze out the full amount of water from this bottle. One squeeze bottle fills less than half a liter of water. As a result, it's better to use on the go, and not the greatest if you need to fill up another container.
Better as an on-the-go filter, this bottle holds under a liter of water.
Credit: Amber King
Best Application
Given the heavier weight and bulky design, we can't recommend this model for backpacking or travel where lightweight gear is necessary as a whole system. Since it does filter out viruses in addition to other stuff, it's a great option for traveling internationally and in the frontcountry.
A great option when traveling internationally. Here we use this system at an Air BnB in Mexico where tap water is prone to viruses.
Credit: Ian McEleney
Its practical application is pretty limited considering how heavy and bulky the bottle is. However, we do like that you can use the Sawyer Micro Squeeze filter when filtering out viruses isn't a priority, which adds versatility to this system.
Value
The Sawyer S2 is priced right for its niche, filtering out viruses, especially if you plan to use it for frontcountry applications in developing countries. It's a decent value for the price and comes with a smaller filter that can be used on its own when viruses aren't an issue.
Conclusion
While the Sawyer S2 certainly does have a niche in filtering out viruses, we were impressed by its bulky nature and use details. The water quality is sub-par, leaving black particulates when all water is squeezed out. The flow is okay but works. While this filtration system is certainly lack-luster, it does have its place for traveling internationally in a front-country setting.
