Where do you get water?

| Comments (3) | Gear JMT
Behind "what did you eat", "where do you get water" is one of the big questions you get. On the JMT and in the Sierras in general, the answer is "everywhere". I only remember a few stretches of the JMT over 5 miles without some source of water (lake, creek, river, etc.) And for the few stretches where there isn't water, you just need to know in advance and tank up. I carried three water containers: an empty quart-size Gatorade bottle and two 2 liter Platypus canteens, but never carried more than 3 liters of water, even for the dry stretches; if you're moving at 2 miles/hr, then you really only need about 3 liters even for a 5 mile stretch, since you can't absorb more than about 1l/hr.

This is only a partial answer, though, since it's not considered a great idea to drink untreated surface water (though see this article). There are three basic treatment options:

  • Chemical treatment (e.g., iodine, chlorine)
  • Water filters
  • Electronic devices (steripen, miox)

The idea with chemical treatment is simple: you fill your containers, drop the chemicals into them, mix, and wait. Old-style chemical treatment really was terrible: it was slow and left a bad aftertaste. Things have gotten a lot better, though. The best chemica treatment is probably Aquamira, which works in 15 minutes and leaves only a very minimal aftertaste. I've used Aquamira drops, which require mixing from two bottles, but Aquamira also comes in tablet form which I'm informed by friends is more convenient. The big advantage of chemical treatment is that it's ultralight. The disadvantage is that it's slow and can be problematic with marginal water sources: if the water is cloudy you need to prefilter it to remove as much of the particulates as you can. If you are trying to get water out of a shallow stream, you also can have trouble getting your container to actually fill. Finally, it's still annoying to have to wait 15 minutes to drink.

The other traditional alternative is water filters: your typical filter is a pump attached to some sort of filtration element. You drop the input hose in the water and attach the output hose to your bottles. When you pump, the water is forced through the filter and into your bottles. The big advantage of a filter is that it's fast, can work even with very shallow water (since it's a pump), and removes all particulates. Of course, if the water is really dirty, the filter can clog, but the better filters are pretty good about this. Many of them come with prefilters that will remove most of the larger particulates. You can also get two kinds of non-pump filters: small filters that fit over the mouth of a water bottle (this only seems suitable for very limited circumstances) and bag filters (e.g., the ULA Amigo). I've seen the Amigo in action but never tried it myself so can't vouch for it. The big disadvantage of filters is weight: the overall weight of my filter (I use a Katadyn Hiker Pro) is 440g.

The newer alternative is electronic purifiers. These come in two varieties: ultraviolet irradiators (Steripen) and electrolytic (MIOX). [As far as I can tell the MIOX is just making chlorine dioxide, the active ingredient in Aquamira, electrolytically.] Of these two, the Steripen looks better: it's more convenient and seems faster (about 1-2 minutes). I'm not sure I see a huge benefit here: they're both a lot heavier than Aquamira and have a lot of the same drawbacks in terms of marginal water sources that any chemical system has.

I currently use a Katadyn Hiker Pro, and carry Aquamira as backup. The difference between the Hiker and the Hiker Pro is that the Pro has quick connect hose fittings, which is somewhat more convenient. I also bought a Platypus Filter Link so I can pump right into my Platypus containers. This works well, except that there's no vent in the Filter Link, so when you get to the very top of the container, you start to get air back pressure. This seems like it would be fixable by punching an air hole.


How well do these mechanisms address the various types of contaminants? (That is, bacteria vs heavy metals vs pesticides vs... etc.)

As far as a I know, none of them meaningfully remove any chemical contaminants--though the Katadyn Hiker has a carbon core which might help a little bit. The filters don't remove viruses but the chemicals will kill them, as, I suspect, will the Steripen and MIOX.

There are some filters that will remove viruses:


There are also forward osmosis systems that will screen down to .0005 microns (5 Angstroms). This would filter out most organic molecules and I believe most heavy metals. But there doesn't appear to be any testing data on this:


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