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Rated 5 out of 5 by from Platypus - as unique as its namesake! I bought this filter after seeing one work during a backpack trip with a friend. I can't sing enough praise for the unit! Works flawlessly, filtering four liters in less than four minutes. It weighs slight less than my old hand-pump filter and takes up about the same back space. And in camp, the clean reservoir serves as a convenient storage and dispensing canteen. I kept the dirty reservoir filled and ready overnight, making mornings a lot easier. Two concerns: water source can't be silty or slimy otherwise the filter might clog, and you can't let the filter freeze so late fall and winter use would be limited.
Date published: 2014-09-01
Rated 5 out of 5 by from Huge step forward in modern science The creation of this system should be celebrated by all outdoors people. It takes the place of pumping water (essentially the worst part of backpacking) and replaces it with lounging next to a quiet stream. I have dreamed about this. It is worth every penny. My only fear, is that one day I will be way up somewhere with a group of friends backpacking, and at this point all my friends rely solely on me to bring this filtration system. We stop for a drink, fill the bag, and the filter doesn't work. Because, at that point.....there will be a straight up mutiny. ...... It will be a wild scene. But until that day comes. I will keep using this system and loaning it out to all my friends who refuse to pay for it.
Date published: 2014-04-21
Rated 5 out of 5 by from Simple, light, effective - just about perfect This is a great, great system. Works as advertised - fast flow rate, gets marginal water sparkling clean (and safe) fast. Would be a good idea to use a cup to fill the dirty bladder when you are working with a shallow source, trickling stream, etc., as the bag itself is almost impossible to fill without some depth or a strong flow. And mind the little cap that secures the hose to the clean bag (it can come off) as well as the shutoff clamp, and don't drop the filter cartridge. With a little careful handling, this is just a far superior system to pump filters - both easier and faster.
Date published: 2014-08-04
Rated 4 out of 5 by from Great at first, less so after much use I have a few different water filtration systems. I got this after a friend brought one on a week long trip, and I couldn't believe how fast it is. However after using this for a while (50ish liters) I found the filter completely clogged despite the ridiculously high rating as to the number of liters it can filter. Some back flushing helped, but it was never the same. If it gets cold where you are (anywhere in the mountain west) this is unusable when it freezes, so store it in your tent overnight. I found that "burping it" helped the water flow, and backflushing both before and after you filter.
Date published: 2015-03-17
Rated 5 out of 5 by from Excellent Choice for Groups Used this filter on a backpacking trip in Shenandoah. Effortlessly filtered water for our group while I lounged on the rocks. Only complaints are that the dirty bag doesn't seal better making it vulnerable to leakage if you lay it on the ground and it isn't sealed properly and that the cap for clean bag isn't attached to the bag somehow making it easy to drop in the stream or misplace. Used both bags to transport water 1/2 mile to our dry camp without issue. Material appears to be very durable. Easy to use. Everything fits in the bag it came with and doesn't take up much space.
Date published: 2014-07-03
Rated 5 out of 5 by from My Favorite I bought this less than a year ago, to take for a larger group (7), so I wouldn't pump my arms to oblivion. I've used it on every trip since. It holds up really well, and is easy to clean in the field - I was really relieved about this when it clogged in Utah's backcountry. The whole thing is well-built, lightweight, and handles a ton of water with little-to-no effort. It's intuitive, packs up small, and sturdy. You could also just put a bite valve on the clean hose and put it in your pack as a dual-purpose item. My only criticism is that the cap for the clean hose is really small and easy to lose (as I have proven). It's also easy to rig a replacement with any number of other gear, so I'm not going to dock it for that. I can't recommend this enough.
Date published: 2014-07-25
Rated 1 out of 5 by from Redesign Ruins a Great Product In concept, and in filtering functionality, this filter is fantastic. I purchased one in late 2013 and it got me and my hiking companions around the Wonderland Trail at Mt. Rainier the following summer without issue. Unfortunately, after a couple of moves, that filter was lost. I purchased a new one in May 2016 for an anticipated trip in Alaska. While the filter and gravity feed retain their same functionality, and the bags are still Platypus' great taste-free bags, the grommets and hanging straps have been completely redesigned since the 2013 model. It didn't take more than a few days for the plastic grommets to pull free of the reservoirs, and for the strap to rip through the edging when the bag was hung from a tree branch. So now the bags can't be hung, at least not when full, which sort of seems like a problem for a gravity filter.
Date published: 2016-07-20
Rated 5 out of 5 by from Above & beyond I purchased this product about a year and a half ago and never felt the need to review it, it worked as advertised. Over the Easter weekend 4 of us were on a 4 day trip. On the last night we were very low on water and found a stock tank. This was the nastiest, most disgusting I have ever had to work with. After pre-filtering thru a bandana, we were able to filter 8 liters of water. This water did not taste great and was not a pleasant color, but was drinkable and we were able to finish our trip and no one got sick. If we had any other source of water I would not have tried this, but I felt we put this product to the test under the most extreme conditions and it delivered. After that hike I did backwash about 20 liters of bleach added water to clean out the filter, but have used it since and the filter again provides clean, great tasting, clear water.
Date published: 2014-05-26
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Questions & Answers

Can the clean bag be used as a water bladder with the addition of a bite valve?

Asked by: onesojourner
​Yes, the clean bag can be used as a hydration reservoir.
Answered by: REIservice
Date published: 2017-05-21

How can the clean bag be cleaned and dried?

Asked by: Ryan
​To disinfect your Platypus filtration system, fill it with a solution of unscented household bleach and water, using a concentration of 2-5 drops per liter of water. Close and swirl for 10 seconds. Leave filled overnight. Hang to dry after washing/cleaning.
Answered by: REIservice
Date published: 2017-09-15

I recently purchased a women's small 50 Osprey anti-gravity backpack. Would the 2L or 4L work best?

Asked by: letigre00
One 4 liter bag from the Gravityworks Water Filter System will fit inside the hydration pocket on the Osprey Aura 50 pack.
Answered by: REIservice
Date published: 2015-09-20

Do you sell the quick disconnect hose with the 45 degree quick disconnect shown in the picture connecting the dirty water bag to the filter? I just need that part of the hose. I see them on here without the 45 degree disconnect.

Asked by: Jared
We do not sell the replacement hose kit for this filter system. It can be ordered directly from the Platypus website.
Answered by: REIservice
Date published: 2017-07-18

I do not see where you can purchase the replacement filter separately, is there one?

Asked by: dfordice
The compatible replacement cartridge is available here:
Answered by: REIservice
Date published: 2017-06-22

Does platypus make a 4 liter system with the bottle kit? I don't see the need for me to have the clean bag and I see the 2 liter system with bottle kit but would prefer a 4 liter and don't see one listed here. Thanks.

Asked by: mixmasterB
They do not make the 4 liter system with the bottle kit.
Answered by: REIservice
Date published: 2015-09-20

Is the only way to transfer the 4 liters of clean water to a water bottle or resovoir through the zip top? Or does the bottom open up for easy pouring

Asked by: Mamoss22
The hose at the bottom of the clean bag can be disconnected from the filter and used to fill a water bottle or reservoir. The hose has a clamp that can be used to control the flow when filling water bottles.
Answered by: REIservice
Date published: 2017-07-11

Strange/sill question, but is the clean water bag designed to be used by someone as their personal reservoir? I already have a platypus reservoir, and i am buying this gravity filter. So combined, that should suffice for two people, right?

Asked by: IndigoMoon
It is possible to use the clean bag included with the Gravityworks Water Filter System - 4 Liter as your personal reservoir. You would just need to purchase the Platypus Drinking Tube. You could also purchase the Platypus GravityWorks Universal Bottle Adapter and filter water directly from the dirty bag to any personal reservoir.
Answered by: REIservice
Date published: 2015-09-20
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