Gear Review: Platypus Gravityworks (4L)

The Platypus Gravityworks in action, using the steep incline of the rocks that lead to the water, rather than hanging from a tree.

Gear Review:

Platypus Gravityworks (4L)

Pros: Fast and easy to use.

Cons: Must have some kind of elevation to use, so might not be a good fit if you need to filter water while in a canoe, or in very flat, treeless places. Also, not great for winter camping, as the filter will be damaged if frozen.


For my purposes in the backcountry, this is the perfect water filtration solution. Things really slow down out in the woods, so it’s actually a fun activity to set this thing up and watch it work!

The trick to maintaining this filter is pretty simple, and the accompanying instructions are very clear. The backflush technique is just what it sounds like. After letting the water run from the dirty bag down to the clean bag for a few seconds, you raise the clean bag above the dirty bag so the water runs backwards through the system momentarily. This backflushes the filter, and keeps things running smoothly. I do this every time I start to filter another batch. You can also do this whenever the flow starts to seem slower than usual.

I haven’t set a timer yet while filtering the full capacity, but I will update this review with that information after this year’s backpacking trip. I can say, it’s always seemed very fast, especially if you go tend to some other camp chores while you wait. I’ve used this filter for a party of two, as well as a party of four, and was happy with the 4 L capacity.

Please note that this filter will work on almost everything EXCEPT viruses. (Particulate, bacteria, and protozoa are filtered out.) Just to be safe, I boil after filtering, even though I’m pretty confident that the risk of viruses in Algonquin’s lakes is extremely low. Before purchasing the Gravityworks, I looked for reports of water-borne viruses in Ontario and found nothing. I prefer to be overly cautious, even though it costs stove fuel.

Price: $122.49 CAD before tax.