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Reviews > Water Treatment > Filters > Sawyer One-Gallon Gravity System > Test Report by Robb Pratt

SAWYER GRAVITY SYSTEM
TEST SERIES BY ROBB PRATT
FIELD REPORT
December 29, 2021

CLICK HERE TO SKIP TO THE FIELD REPORT

TESTER INFORMATION

NAME: Robb Pratt
EMAIL: unicornv007 AT yahoo.com
AGE: 51
LOCATION: Canton, Michigan, USA
GENDER: M
HEIGHT: 5' 10" (1.80 m)
WEIGHT: 165 lb (74.80 kg)

I backpacked sporadically growing up and rediscovered it back in 2011. Since then, I've taken several weekend trips a year. I also car camp with my family roughly a dozen nights a year when we use tents unless I can convince them I might snore and it would be better for all for me to use my hammock rig. I prefer a light pack (weight without food or water under 20 pounds / 9 kg). My backpacking stomping ground is northern Michigan that has small hills and I typically camp late spring, summer and early fall months.


INITIAL REPORT

PRODUCT INFORMATION & SPECIFICATIONS

Manufacturer: Sawyer
Year of Manufacture: 2021
Manufacturer's Website: WWW.SAWYER.COM
MSRP: US$39.99
Listed Weight:
* Entire System as per Website: 19.52 oz (553 kg)
* Entire System as per Back of Packaging Box: 8 oz (227 g)
Measured Weight: 8.1oz (230 g) with breakdown by part:
* Dirty Water Bag + Cap: 3.7 oz (104 g)
* Filter with Cap: 1.5 oz (43 g)
* Rubber tubing: 1.0 oz (29 g)
* Cleaning syringe: 0.95 oz (27 g)
* Blue threaded cap: 0.2 oz (6 g)
* Gray threaded cap: 0.2 oz (6 g)
* Black plastic hanging brace: 0.2 oz (6 g)
* Threaded cap with hole in it (Bottle coupler): 0.2 oz (6 g)
Listed Size: 12.6 x 7.25 x 2.75 inches (32 x 18.4 x 7 cm)
Measured Size:
* Bag Unrolled is 13.75 x 12 x 2.75 inches (35 x 30.5 x 7 cm)
* Kit rolled up as small as I can make it is 5 x 12 x 2.75 inches (12.7 x 30.5 x 7 cm)
The Sawyer Gravity System is a water filtration system designed to supply clean water using gravity (instead of squeezing or pumping). The system comes with a Sawyer Mini Filter, a 1 Gallon (3.78 liter) water bladder, a cleaning plunger, a bottle coupler, several nozzle attachments, a gravity hose and a plastic hanging brace.
The Sawyer Mini Filter is rated to 0.1 micron filtration (which is required to filter out salmonella, cholera, E. coli, giardia and cryptosporidium). It also boasts of being able to filter out 100% of all microplastics. It is rated to be effective for up to 100,000 gallons (454,609 liters).
The water bladder has a wide mouth opening to help with getting dirty water into the bag and a reinforced handle that is molded to fit comfortably while holding (or act as a hanging location).
While I received the SP160, Sawyer also makes a similar version (SP2160) which includes a clean water bag, a shutoff clamp, inline adapters and a hanging system.

IMAGE 1
Initial Package - Curious Cat for Size

INITIAL IMPRESSIONS

First off, I'm surprised at how light it is. The Sawyer site noted the system as weighing 1.22 lbs (0.530 kg) but it actually comes in at less than half that for the parts once the box is opened and discarded. The back of the Sawer Gravity System package however, notes the weight as 8 oz (227 g). The Sawyer's site did leave me a little confused as to whether the listed weight was for the SP160 or the SP2160 system but the weight on the package was accurate.

As for the parts themselves, I really liked the look of the dirty water bag. The front has a nice forest / mountain picture with the Sawyer branding while the back side has filter cleaning instructions. Both caps thread on and off easily and I especially liked that it had the ability to cap the water bladder on the bottom so it can be used as a reservoir. The rubber hose is thick and durable looking. The cleaning syringe holds 50 ml and the plunger moves easily in and out.

IMAGE 2
All Filter Components


Moving on to the filter itself, one of the key advantages of the Sawyer Mini Filter that I had heard about from following several backpacking YouTube channels is the versatility of the system. It can be used as a gravity system or attached directly to bottles on both sides through the plastic threads molded into the housing. The filter also is very clearly marked with which way water is supposed to flow.

IMAGE 3
Micro Filter Close-Up


Included in the system is a cap with a hole in it that has a plastic washer that can be removed. While I did not find clear instructions, after playing with the filter parts I determined it is actually a coupling that used to make the connection between a single-use, disposable water bottle and the filter. I also did verify that my water bottles screw onto both ends of the filter (though as noted above, the coupling is required on the clean side).

The only piece that I am still somewhat unsure of is the black plastic hanging brace. I have confirmed that it clips into both threaded caps that have nipples on them. The picture on the back of the box indicates this is used when laying the filter on a flat surface so the hose can make a gentle bend downward instead of a sharp 90 degree change.



READING THE INSTRUCTIONS

The Sawyer Gravity System did not come with an instruction book. The only setup guideline I found was on the back of the package.

IMAGE 5
Package Instructions


I did some searching on the Sawyer site but I did not find any additional instructions that explained which connections went where. Thankfully, the connections on the filter are pretty "idiot proof" (Note: I personally confirmed this and am very comfortable fulfilling the role of test dummy). I also have been using gravity filters from another brand for several years so I know some of the pitfalls to avoid. The only location where a mistake can really be made is if one connects the filter backwards, which I learned the hard way one time years ago but that is a different story. Thankfully, I have not repeated that mistake.

Sawyer's site also made several comments about not having the filter below freezing temperatures as if the filter freezes, the water trapped inside will expand and fracture the filter membranes, rendering it ineffective.

For cleaning the filter, I did appreciate that the dirty water bladder had clear instructions on it which explained the process.

IMAGE 4
Cleaning Instructions

TRYING IT OUT

As luck would have it, the day I decided to sit down and experiment with the Sawyer Gravity System, my toilet decided to get into the spirit of things and overflow. It was bad enough it was raining water into the basement.

While I briefly considered both the irony in this - especially how interesting a filtration test it would make, I just couldn't stomach (pun intended) the idea of filtering dirty toilet water that had been filtered though the flooring of a 50 year old house.

Instead (after cleaning up the previous noted mess), I performed basic integrity and flow tests using (clean) tap water.

First off, the dirty water bag holds water and does not leak. The filter connections are easy to attach. After the bag was filled with water, I just turned it up-side-down, removed the small cap and instead installed the spigot cap and attached the hose. Water flowed easily down the line and into the filter.

While I had no leaks around the dirty water connections, I did have a drippage leak (about one every 10 seconds) when using the white flip-open-lid cap to stop flow on the clean side of the filter. Considering I would be in camp and the size of the dirty water bag, I believe this is accepable, especially as I could always screw in a normal Smartwater bottle cap on the filter clean side to halt all flow or even just hang the filter higher than the bag.

From a flow test, I tested it several times and it was consistently around 43 to 45 seconds to filter 2 cups (0.47 L) of tap water. At this rate, I estimate it would take me a little over 3 minutes to fill up the bottles I normally carry when backpacking.

IMAGE 6
Filter Flow Test

SUMMARY

I really like the versatility of the Sawyer Gravity System. As I typically camp and backpack in groups (both with friends and scouts), this gives me the option of taking the entire system or just the filter. I also can connect directly to my water bottles and filter water into those easily. The system is light weight enough that it will fit easily into my pack.


FIELD REPORT

FIELD LOCATIONS AND CONDITIONS

* Trip (10/22 to 10/24) - Camp Teetonkah near Jackson, Michigan, USA for 3 days, 2 nights. Temperatures ranged from 31 to 55F (0 to 13C). While there was no precipitation, as it had rained earlier in the week, the ground was very wet and there was a lot of standing water. This also was a base-camping event but as usual, I packed as if it was a backpacking trip and walked in from my car. My pack weight was approximately 25 pounds (11 kg).

FILTERING PERFORMANCE

For my October camping trip, we had setup base camp roughly 0.5 miles (0.8 km) away from a nearby lake. Early in the mornings, I wandered down to the lake, filled up the dirty water bag and returned to camp to filter water. I also did this in the afternoon as well as filtering from a closer water source that I discovered later.

For lake use, while I found the large mouth on the dirty bag easy to open, I did have a little difficulty filling the whole bag with water as it was fairly cold outside and I didn't want to walk into the lake to submerge the bag using both hands. Using a scoop method, I was only able to get the bag about 3/4 filled with water. I also noted the water had quite a bit of surface dirt and sand. While I considered pre-filtering the water with a bandanna, I decided to continue testing the water filter under these conditions.

During the walk back to camp, I found the the handle's molded shape very comfortably. It did not cut into my fingers at all and even though the walk was only about 10 minutes long, I felt I could have done a "water carry" for significantly longer without a problem.

Back at camp, I threaded a piece of rope through the handle so the dirty water bottle could be suspended at roughly head height. Once I made the necessary hose connections, I was able to filter water into a small, threaded bottle using the threaded adapter. After a few minutes though, the water stopped. I had to unscrew the threaded fitting slightly to provide a path for air to vent. Once that was done, the water filtration resumed. After a few bottles, I switched to the nipple fitting and just placed that fitting into the bottle opening to provide maximum venting.

IMAGE 1
Hands-Free Filtering


While I did not time the filtration, I felt that the water was filling up the bottle as quick as I noted earlier in my testing at home. It handled all of the debris without a problem. The water had a pristine look to it and tasted acceptable to me.

IMAGE 2
Close-up of Water Filtering


After repeating this several times, I felt a more intense test was in order. Okay, in all honesty, I was getting tired of walking to the lake and back just for water. Due to the recent rain, there was a huge,puddle (more like a small pond) behind camp. The water was incredibly murky and very dirty but I took the time to load the water bag with it.

IMAGE 3
Yes, This was Filtered


The Sawyer filter managed to only filter about a third of a bottle before it clogged up. The filtered water also had a slightly yellowish tinge to it. Due to the horrendous nature of the dirty water, this did not surprise me and I was actually (somewhat) hoping to clog the filter with this filthy water to check the cleaning process. BTW, as a side note - the water, while its appearance was not as pristine as from the lake, tasted fine and I did not get sick later.

IMAGE 4
Slightly Yellow Water


I filled up the included Sawyer syringe with clean water and placed it on the clean side of the filter and shot a quick blast of water backwards though the filter. Water came rushing out of the dirty side of the filter. It was that easily to unclog it. I returned to filtering water and managed another third of a bottle before it clogged again. I cannot stress this enough but this water was *really* filthy and I would not normally consider using it as a drinking source unless I was in a dire situation but I really did want to put the Sawyer filter to an extreme test.

This time to unclog the filter, I used my clean water bottle. I threaded it on tight to the filter and simply squeezed the water bottle which blasted all the debris back out of the dirty side of the filter. This worked exceedingly well and I was able to get the flow back to its original speed.

I ended up filtering more water from the lake, filling the bag another two times. I also found a great use for the mysterious black plastic piece. While the pictures on the bag showed it being used if the bag was laying on its side on a table, I actually attached it backwards to the filter itself using the gray spigot attachment. This allowed me to hang it from top of the bag when not in use. As the end of the spigot was now higher than the water in the bag, flow would cease and the filter provided easy water access in camp when I wanted it. I simply moved the end of the tube down lower than the bag for flow to start.

IMAGE 5
Hanging Up Filter End


NIGHT TIME STORAGE

Both nights, the temperature was predicted to be right around freezing with a frost warning. I opted to play it safe and removed the filter cartridge, shaking the water out of it as best I could. I then put it into a Ziploc bag. The filter was small enough that it fit perfectly in the breast-pocket of my sweatshirt which I then wore to bed. I managed to sleep the entire night, break camp the next day and even drive home with it in my pocket on our last day. It never caused any discomfort with either sleeping or doing activities. I also noted that very little water was left in the Ziploc bag so simply shaking it out was effective enough to get most of the water out of it.

At home, I did a quick integrity test (using my mouth, I tried to blow air back through the clean end). I was not able to pass air to the dirty side through the filter which is an indicator the filter is still okay.

PROS

* Dirty Water Back Comfortable to Hold / Carry
* Filter Ease to Clean / Unclog
* Attachment Versatility, especially Threading Directly to Bottles
* Filter Size was Compact Enough to Keep On Self at Night Without Problem
* Water Filtration Speed was Acceptable to Fill All Bottles

CONS

* No Storage Bag Included for Organizing Gear
* No Filter Cap for Dirty Side to Assist with Nighttime Storage
* Minor Difficulty Filling Dirty Water Bottle

SUMMARY

While I'm not getting out as much as I'd like during the winter season in the midwest, I have enjoyed using the Sawyer Gravity filter. Overall, the filter both easy and a pleasure to use. I especially like having access to excess water in camp for various tasks throughout the day.

This concludes my field report. Please check back in two months for the long-term report. I want to thank both BackpackGearTest.org and Saywer for letting me take part int his test.

This report was created with the BackpackGearTest.org Report Writer Version 1. Copyright 2022. All rights reserved.

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