Stomach bugs suck. So do heavy backpacks. Luckily, backpackers who enjoy neither lugging heavy items nor digging a cat-hole every hour can find a light but effective water purification system if they know what to look for.
Considering their frequent use and critical role in the backcountry, purification systems often seem to undergo minimal scrutiny from those that use them. In my experience, many backpackers tend to stick with whatever system they first used when introduced to backcountry travel, even though there is an increasing variety of ever-improving options.
I’ll offer my top two picks of purification tools – one a filter system and the other a chemical treatment – with the hope that more backpackers will be increasingly thoughtful about what they toss in their backpack (that means getting nerdy about pack-weight!) and will embrace the improving technology in this area.
The Sawyer Squeeze
Nuts and bolts:
The main component of this system is a compact, 2.7-ounce filter, which is sold along with lightweight bladders. Absent are the hose lines and the hand pump found on traditional filtration systems. Instead, the user fills a bladder with untreated water, screws the filter directly onto the bladder’s cap, and applies pressure to the bladder.
The treated water exits through a pop-up, sport bottle-style mouthpiece, making it possible to drink the water immediately, although one can simply use the mouthpiece to fill other bladders or water bottles. Sawyer also offers a smaller version of this filter called the Sawyer Mini, which weighs about half as much as the Squeeze but sacrifices flow rate and ease of use.
The Squeeze usually retails between $30 to $40, depending on how many bladders the system is sold with. Considering its claimed million-gallon product life, this makes for an incredibly cost-effective treatment method. The intake end of the filter fits the neck of any standard disposable water or soda bottle, which some users prefer for water storage over the bladders. The hollow-fiber filter piece itself removes bacteria and protozoa along with solid sediment.
Like most filters, its effectiveness can be compromised if water that is not flushed out after use freezes and expands; it does not guard against viruses. While treatment of a couple liters comes quickly, its ease of use for large groups does not rival that of a pump filter.
Nuts and bolts:
A set is composed of two plastic dropper bottles—“Part A” and “Part B”—each containing a single fluid ounce of different clear chemical mixtures. The set weighs three ounces total. When droplets are combined in a mixing cap (or the dropper bottle caps) and left to react for five minutes, the result is a chlorine dioxide solution capable of eliminating all pathogens when added to untreated water and left for another 15 minutes.
Seven drops of each “part” (14 drops in total) treat a liter of water; one set treats up to 30 gallons. While the manufacturer discourages any use inconsistent with its instructions, I have had success premixing the two solutions in a separate teeny dropper bottle at the beginning of a day on trail. Doing so means that filling up while on the move takes only as long as filling a water bottle and squeezing off fourteen drops of “pre-mix” – then I’ll keep hiking while the water treats itself on my back.
With no moving or breakable parts, the system is dead simple, despite the mystique of performing some low-key chemistry in the backcountry. A mixture of the two parts turns yellow when activated, so you are never left guessing if it’s going to work. Unlike many other forms of water treatment, it is effective against viruses in addition to bacteria and protozoa.
Chlorine dioxide sets itself apart from iodine and chlorine treatments with an extremely minimal difference in residual taste as well as a lack of pressing health concerns with consistent, long-term use (it’s commonly used to treat municipal water supplies in the U.S.). The system is very compact and compatible with all water-carrying vessels.
The 15-minute wait time (30 minutes if the water is exceptionally cold or turbid) means that water cannot be consumed instantly, so a backpacker on the move can’t save weight by drinking at the water source. Since there is no filter, the system does not remove sediments that may be suspended in untreated water. A single set will likely struggle to meet the needs of even a small group in a timely manner.