Gravitating Towards a Better Filtration System

Gear Review: The Sawyer One Gallon Gravity Assisted Water Filtration System

*Note that BecauseItzThere receives NO compensation of any kind from any outfitter. The products you see reviewed here are purchased with our own funds and objectively reviewed under field conditions.*

Our recent multi-day hike of the Standing Indian Loop forced me to re-think an old problem that I had dealt with before, but never solved entirely to my satisfaction. Namely, a sustainable system for gathering and filtering water. Water sources found in the wild are not always pure, and it’s hard to know what the good ones are from the bad (Clean looking water can in fact be entirely contaminated.) Inevitably any hiker is going to be forced to ‘water up’ from a source that, if they’d had their druthers, they would have passed by.

Standing Indian Loop/April 2018
In the outdoors, who knows what’s been in the water you’re drinking?

It is simply a good practice to treat any water obtained from natural source. In areas where livestock, human contamination or beaver activity is present, this is mandatory. Further afield in true wilderness, it may not be mandatory, but is still a good idea.

There are many methods of purifying water. To sum them up…

  • Boiling. Old and true and reliable…But time consuming.
  • Chemical treatments. Generally effective but not admired for their taste.
  • Gadgets designed for filtering. A good choice for a variety of reasons; but almost all gadgets have down sides. See my article on the Forgotten Essential.

For years I have relied on a gadget. This was a hand-crank pump sold by MSR called the Sweetwater. Though it was much easier to use than many other hand pumps I have encountered, the Sweetwater still requires a lot of sweat investment to pump out a sizable quantity of water. It is also somewhat heavy for backpacking, and over the years I had had serious cause to question its reliability. I have had many breakdowns of the Sweetwater in the field and ended up replacing it once. It was never entirely to my liking.

My old ‘dang old infernal’ MSR Sweetwater pump filter

Years had passed since I purchased the last filter, so I decided to go back to the drawing board and review all the possible options. There were several items on the market that a decade ago hadn’t been sufficiently developed yet to make them affordable or viable or both.

New options include….

  • Better gravity assisted filters
  • UV light sterilizers
  • Portable ‘drink as you go’ filters and ‘Life Straws’.

Against this we have my own list of requirements…I am looking for a filter that is:

  • Lightweight
  • Reliable
  • Easy to operate
  • Could filter a relatively large quantity of water in a short time (so we could ‘filter as we go.’)
  • Is not overly expensive

After reviewing all the possible options, we decided a gravity assisted filtering system was best. I do not consider UV sterilizing devices to be reliable enough. The new mini filters made by Sawyer, such as the Mini and Squeeze, are intriguing, but ultimately we felt these were either not compatible with our current hydration system or would force us to make home-made modifications to the systems (cutting and splicing hoses, etc.)  I had also heard very good things about the gravity systems.

The industry leader in the field of gravity assisted filtering systems is the Platypus Gravityworks, an offering by a leading brand which has been well reviewed by a wide variety of objective sources. We thought it’s $120 price tag to be a bit steep. Both MSR and Sawyer make compatible products, and these are also well reviewed, but also pricey.

In the end we chose to give the Sawyer One Gallon Water Filtration system a go. There are various permutations of this product on the market but the one we purchased is the 2 big system, which retails for about 69.95.

Sawyer One Gallon Filtration System

This system is based on the Sawyer Mini. In fact…effectively it IS the Mini with a couple of plastic container bags, some tubing and some threaded hose adapters. If you have a Mini already, you could probably purchase the accessory pack and make one of these yourself…or, you could just get this system and save yourself the work.

Though crude, we found this system to be very effective. At just 12 ounces it weighs about the same as the Gravityworks system, and Sawyer claims that it will filter an entire gallon (3.8 liters) of water in about 5 mins. My own field testing showed this to be reasonably accurate. In fact, it filtered much faster than my Sweetwater did and with almost no comparable effort, making it very much an upgrade.

The system comes with two bags, a ‘clean’ bag (conveniently marked as such) and a ‘dirty’ bag (which for some reason is marked with the Sawyer “We keep you outdoors” logo. You could write dirty on it with a marker I guess.) The ‘dirty’ bag has a wide mouth that makes filling easy.

The ‘dirty’ bag collects from sketchy water source

To operate, all you need to do is fill the dirty bag, hang it in a tree or other convenient location about 4 to 5 feet off the ground, then attach the hose and filter setup (the Mini, basically) and attach the clean back to the other end of the hose. Release the crimp catch and gravity will quickly do the rest.

Hang by the strap…
…Attach the hose…
…Set…And forget!!!

We field tested this system out on the Standing Indian Loop and had no issues with operation at all. If you can find water it will do the trick.

Another added benefit to gravity assisted systems is, the bags allow you to water up any time you pass a source, so you don’t have to spend time pumping water at the source for later use. You can filter when you get to camp. You can do this anyway by carrying multiple water containers, of course (as long as you keep clear which one is contaminated and which one is not) but if you are going to carry a bunch of water bags, well, heck, why not use them and gravity to do the filtering?

There are some drawbacks. For one thing the bags themselves are made of a rather stiff plastic and don’t fold well…you give up something with the difference in price with the more premium systems and this is part of it. They are however durable.

Another issue I noted is that filling the bag is easy if you have a stream or deep pool available. But if you have only a very shallow water source, as we did in one campsite on the trail, filling it becomes problematic. Just imagine what would happen if you lowered a milk carton, say, into a bathtub with an inch of water in it. In practice it would be very hard to make the water run into the carton. So it is with the bag. I had to scoop out a little depression in the stream bottom and fit the bag into it…even then, it took a couple of trips to and from camp get a full gallon.

In these situations, a pump style filter clearly has an advantage. I assume this would be a drawback of the more expensive gravity assisted systems as well.

The bag also hangs just a bit awkwardly…sometimes you have to sort of tip and jiggle bag and hose around before the water obeys gravity and starts flowing correctly. But once working it usually keeps on working.

However, these are relatively minor complaints for a system that, at a $70 price tag, will quickly and efficiently filter large amounts of water for you, and do so at very little cost in weight.

Gear / April 2018

At some point in the future we may go to one of the higher end systems, but I think this system will do for the foreseeable future. Reliability so far has been excellent but we haven’t seen what the Mini will do a few months or years out. It does have a good track record, though, and all the components are easily replaced (the bags cost about $15.)

We are happy with our Sawyer One Gallon Gravity Filtration System and would recommend it strongly at the price.



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