Gear Review: Platypus GravityWorks Water Filter

Platypus GravityWorks Water Filter

Platypus GravityWorks Water Filter
$120, 12 oz. (including mesh stuff sack)

There are two things I don’t like about filtering water in the backcountry: the weight of a filter in my pack and the time that pumping water requires. The GravityWorks filter addresses both gripes, but especially the latter. Here’s a filter that requires no pumping. It’s easy: Fill the four-liter reservoir labeled “dirty” with water from a creek or other source and seal its opening. Hang it from a tree branch or set it on elevated ground. Attach the quick-release hose-and-filter unit to the dirty reservoir, and then the “clean” reservoir to the hose below the filter. When you set the clean reservoir down in a spot lower than the dirty one, gravity does the work of filtering for you. The entire setup takes less than a minute, and you can go about other tasks or kick back and relax while the GravityWorks filters four liters of water in a speedy two and a half minutes.

The larger your party, the greater this unit’s utility because of its speed, reliability, and simplicity. The design eliminates any possibility of contaminating the “clean” reservoir with untreated water because it can only be filled through its connection to the filter. The filter is easily backwashed by elevating the clean reservoir, once it has water in it, higher than the dirty one, forcing water backward through the filter to flush it out. Platypus recommends back-flushing the filter before each use—though I back-flushed only a few times over the course of a four-day backpacking trip in the Tetons and two hikes totaling eight days in Idaho’s Sawtooths, without problems.

At 12 oz. and roughly the size of a liter bottle, the unit compares to many pump filters. The clean reservoir can be used for a backcountry shower, too; and the two reservoirs effectively serve as vessels for carrying up to eight liters of water, whether to a campsite a distance from your water source or in a place where you have to carry extra water.

But the real appeal, to me, is the simplicity, reliability—and that I don’t have to pump.

BUY IT NOW You can support my work on this blog by clicking any of these links to buy a Platypus GravityWorks Water Filter at,, or


Hi, I’m Michael Lanza, the creator of The Big Outside, recognized as a top outdoors blog by USA Today and others. I invite you to click here to sign up for my FREE email newsletter, or enter your email address in the box in the left sidebar or at the bottom of this story. And follow my adventures on Facebook, Twitter, and Instagram.


See my review of the Katadyn Base Camp Pro 10L gravity filter and all of my reviews of water filters and my reviews of backpacking gear.

NOTE: I tested gear for Backpacker Magazine for 20 years. At The Big Outside, I review only what I consider the best outdoor gear and apparel. See categorized menus of all of my gear reviews at The Big Outside.

—Michael Lanza


You live for the outdoors. The Big Outside helps you get out there. Don’t miss any stories. Subscribe now!



Gear Review: Cocoon Ultralight AirCore Pillow

Gear Review: Mountain Hardwear Super Power Hoody Jacket


Leave a Comment

3 thoughts on “Gear Review: Platypus GravityWorks Water Filter”

    • Yes, although I need to regularly backflush it, which doesn’t take long. It’s possible I need to replace the filter, which I see priced at $55, but whenever I backflush it, it then works just fine.