The Platypus GravityWorks is a gravity-powered water filtration system designed for painless water filtration for individuals or groups. The inline filter connects via plastic tubing between two bags – a clean bag and a dirty bag. These bags come in three sizes, 2L, 4L, and 6L.
You fill one bag (the dirty bag), attach the hoses, filter, and clean bag, and then hang the bag (or otherwise elevate it) and wait for gravity to do the work. It’s more complex than some other water filters available but certainly doesn’t take much to understand. If you still don’t have a great mental image of what’s going on, it’s this: dirty water in one bag travels out via hose, through the filter, and enters the second bag as clean water. Make sense? I hope so.
Here’s everything you need to know about the Platypus GravityWorks Water Filter System and whether it’s worth bringing along on your next outdoor adventure.
Testing Conditions
I have used the Platypus GravityWorks in high alpine group environments and while backpacking in the desert when water sources were few and far between. I’ve used it to filter beautiful alpine lake water that likely had no business being run through a filter and I’ve used it with scummy, silty desert streams that I only drank from because I desired to live.
Pros and Cons
+ Painlessly filter up to 6L of water – set it and forget it
+ Carry up to 12L of water for long hauls
+ Great for groups, couples, or arid environments
+ Turns even murky water into clean drinkable water
+Available in three sizes – 2L, 4L, and 6L
– Bulkier than other options
– Susceptible to freezing and breaking
– Multiple pieces means more to keep track of
– On the more expensive side as far as water filters go
The Specs
The following information reflects the 6L version of the Platypus GravityWorks. If you would like to see specifics on the 4L version, you can find them here. If you’re interested in the 2L version, that’s here.
- Weight: 12.3 oz / 350 g
- Bag Length: 19.5 in / 50 cm
- Filters: Bacteria, particulate, and protozoa
- Filter pore size (microns): 0.2
- Flow (L/min): 1.75 liters per min
- Cartridge life: 1,500 liters
- Bag Material: Polyethylene
- Country of Origin: Assembled in the USA with domestic and imported materials
- Sizes: 2L, 4L, 6L
- Color: Transparent plastic
- MSRP: $134.95
The Features
- No pumping – fill the dirty reservoir, hang it
- Filters up to 1.75 liters per minute with a microfilter lifetime of up to 1,500 liters of water
- Every microfilter is tested to ensure it meets EPA & NSF guidelines for the removal of 99.9999% of bacteria and 99.9% of protozoa (including Giardia, Cryptosporidium, E. coli, Salmonella, and Cholera).
- Stows smaller than most 1L bottles.
- 12-liter (6L filtered + 6L unfiltered) total capacity or groups.
- Microfilter can be backflushed in four seconds
- Hundreds of tiny, hollow fibers enable the microfilter to filter water faster
- Includes: Clean reservoir (6L), dirty reservoir (6L), hollow fiber microfilter, hoses, shutoff clamp, and storage sack
Photo Gallery
The Good
The Water Quality: The Platypus GravityWorks does an excellent job of filtering water. The only potential drawback to the filtered water is that it’s not guaranteed free from viruses, chemicals, or pollutants. That said, having any of these present in your water source is generally the exception to the rule and you (should) know ahead of time if you’re going to need to contend with any of them. As far as bacteria, protozoa, and particulates are concerned, the GravityWorks has you covered.
The Ease of Use: The Platypus GravityWorks is a bit more complicated to set up than other water filters (more on this below), but once you have it ready to go, filtering water is incredibly simple. You literally just leave it alone and wait for gravity to do the work. The water moves from the dirty bag, through the filter, and then fills up the clean bag with ready-to-drink water – much easier than squeezing water out of a water bottle a little bit at a time.
The Storage: One of the nice things about the GravityWorks system (particularly the 6L version) is that you now have a large storage capacity – up to 12L with the 6L version. This is great for groups or for when water sources are inconveniently located and/or away from camp. It’s also great to be able to filter 6L of water at a time.
The Okay
The Set-Up: The Platypus GravityWorks can be a bit tricky to set up. It’s five individual pieces – two bags, two tubes, and one filter – and you’ll need to elevate one of the bags to get the flow moving once you’re ready to filter. Certainly more complicated than screwing a filter onto a bottle and squeezing. Once you figure out the setup, it’s not bad, but it can be intimidating at first.
The Compactness: A drawback of the Platypus GravityWorks compared to other water filters (although not necessarily others of the gravity variety) is the bulk of the system. True, it does back down nicely, but it’s not something you’ll quickly lose in your pack.
The Price: One thing that you’ll notice immediately when investigating the GravityWorks is the price. While not absurdly expensive, it’s still one of the more expensive options available. The 6L version runs $135 (as of this article’s publication), the 4L goes for $120, and the 2L is $110.
The Bad
The Pieces: Probably my least favorite thing about the Platypus GravityWorks is the fact that it requires five individual pieces to function. The two reservoirs, the filter, and the two (different/unique) hoses to connect the filter to the bags. Once, I was missing a piece of tubing and instead of effortlessly being able to filter from one bag to another, I had to manually fill bottles one at a time. Admittedly, my fault, but not something that would happen with a less complex filter. Platypus even sells replacement reservoirs, filters, and hoses in the case you misplace yours.
The Freezing: As with all hollow fiber filters, the GravityWorks is susceptible to freezing. You cannot let the filter freeze or residual water in the filter can expand and damage the filter rendering it ineffective. If you’re going to be out for cold nights, this means sleeping with the filter portion of your GravityWorks in your sleeping bag (or otherwise insulating it during the night). And if you’re out in below-freezing temperatures during the day, you may need to look for a different water filter.
Who is it for?
Solo Backpackers: In its 6L version the Platypus GravityWorks is only a great move for solo backpackers who know ahead of time that they’re going to have very large water carries. If you’ll be backpacking in an area where water will be more readily available and won’t be the primary concern of your time outdoors, you can probably pass on the GravityWorks (or just go with the 2L version).
Couples: The Platypus GravityWorks can be a great option for couples – especially if water isn’t going to be readily available and you expect to be carrying 3+ liters at a time. Just make sure you’re not planning on getting separated if this will be the only water filter you choose to carry between the two of you.
Groups: In its 6L version, the Platypus GravityWorks is an excellent choice for groups. I would say it does a great job filtering for three – maybe four – people, but you would want a second one if you’re going to be in a group of 5+. At that point, you would probably want (at least) one backup filter anyway. GravityWorks for groups (see what I did there?)
Popular Alternatives
| WATER TREATMENT | CAPACITY | PRICE | WEIGHT | MEDIUM | REMOVES |
|---|---|---|---|---|---|
| Platypus GravityWorks 6L | 6L | $135 | 12.3 oz / 350 g | Hollow fiber | Bacteria, particulate, and protozoa |
| Platypus GravityWorks 4L | 4L | $120 | 11.5 oz / 326 g | Hollow fiber | Bacteria, particulate, and protozoa |
| Platypus GravityWorks 2L | 2L | $110 | 10.9 / 310 g | Hollow fiber | Bacteria, particulate, and protozoa |
| MSR AutoFlow XL | 10L | $110 | 12 oz / 340 g | Hollow fiber | Bacteria, particulate, and protozoa |
| LifeStraw Peak Gravity | 3L | $60 | 8.1 oz / 230 g | Hollow fiber | Bacteria, particulate, and protozoa |
| MSR Trail Base Gravity | 4L | $160 | 18 oz / 510 g | Hollow fiber | Bacteria, particulate, and protozoa |
| Katadyn Gravity BeFree 3L | 3L | $75 | 6.8 oz / 193 g | Hollow fiber | Bacteria, particulate, and protozoa |
| Katadyn Gravity BeFree 6L | 6L | $110 | 8.9 oz / 252 g | Hollow fiber | Bacteria, particulate, and protozoa |
| Katadyn BeFree Gravity 10L | 10L | $125 | 10.7 oz / 303 g | Hollow fiber | Bacteria, particulate, and protozoa |
Wrap Up
The Platypus GravityWorks is a great water filter. It’s definitely in my rotation and if a particular outdoor adventure calls for it (filtering for a couple or group), few water sources, or long water carries, it’s my go-to.
It’s not the lightest, most compact, or least expensive filter available, but it’s worth any inconvenience when you can painlessly filter six liters of water at a time. Filtering that much water with a squeeze filter is a thing of hiker nightmares.
Questions, comments, or personal experience with the Platypus GravityWorks? Leave a comment below or get in touch and let me know!
Check out the Platypus GravityWorks here.
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