A chemical water treatment system, Aquamira stands out for being incredibly lightweight, compact, practical, and easy to use. This is the ideal method for hikers and backpackers trying to go light and fast.
The Water Treatment Drops fell smack dab in the middle of our review in the overall performance metric. There are pluses and minuses to this water treatment method.
Aquamira is a lightweight solution to purifying water in the backcountry.
The active ingredient in these drops is chlorine dioxide, which doesn't contain chlorine. (Think bleach, but less harmful.) When researching on the Internet, it seems as though there is confusion as to what Aquamira actually treats, so we emailed them to get the full scoop. As of November 2018, it was approved by the EPA as a purifier, which means that it eliminates all pathogens: bacteria, protozoa, and viruses, which is more than most filters. There is a difference in incubation time for some of the different organisms, but after four hours the drops are effective on everything, including Giardia and the hard-shelled Cryptosporidium.
It is trustworthy and is an excellent method for particularly contaminated water sources since it works in a broader variety of diseases and can also treat the water on the threads of your bottle. The downside? You are adding a tiny bit of chemical to your water - and it takes a really long time to kill everything. However, whereas iodine may not be healthy for you to ingest over extended periods of time, Aquamira drops are not harmful if used as directed, according to Aquamira. If you are looking for a similarly light, non-chemical treatment, the Sawyer Mini is a small filter option.
We interviewed a couple who thru-hiked the Appalachian Trail to see what they used for over 2,000 miles of hiking. They started their journey with a SteriPEN as their water treatment method because it was lighter than all the pump filters on the market, worked fast, and treated viruses. However, they soon became frustrated because the batteries would wear out very quickly. Eventually, the SteriPEN was broken after getting wet in a rainstorm, and so the couple switched to Water Treatment Drops by Aquamira for the remainder of their hike, which was a more reliable system. They said that in their experience on the trail this was by far the most common method used by other hikers.
The taste of the chlorine dioxide is not bad. It adds a faint sterile flavor to the water, or some say it is citrusy. In the case of really gross water, it improves the taste of the water and eliminates odors. Aquamira does not filter out particulate as do all of the pumps, so try not to scoop up silty water. If you know, you'll be somewhere with particularly silty water, consider bringing some other kind of filtration method, either in combination with Aquamira or on its own. The Aquamira Frontier Max filters out viruses and particulate, but is incredibly slow; we prefer the MSR Guardian and Sawyer S2 Foam Filter for purifying from viruses.
Adding Water Treatment Drops to water. This method is by far the most popular method for thru-hikers and lightweight backpackers due to its inexpensive price and extreme light weight.
Ease of Use
Though using these drops requires an extra step other than just dropping a tablet in your water (like the Katadyne Micropur), it is still straightforward. The directions state that for each liter, add seven drops from each bottle, part A, and part B, and wait five minutes for the mixture to activate and turn yellow. Then add it to your water and wait another 30 minutes for bacteria and viruses, 40 minutes for Giardia, and 4 hours for Cryptosporidium (AquaTabs do not eliminate Cryptosporidium at all).
After four hours, everything should be eliminated. It is not uncommon to lose the little caps that come with these bottles. If you do, you can substitute the actual container lids to mix the chemicals - or use them in addition to the mixing cap if you have several people who want to treat their water at once.
We prefer Aquamira over MSR AquaTabs because you can adjust the number of chemicals you need for the volume of your water container. For instance, if you have a three-liter bladder, you can measure out the appropriate amount to treat exactly that.
We found the Aquatabs less versatile since they come in tablets meant to treat two liters of water each, so if you have a three-liter bladder, you either overtreat or undertreat for two.
The 2 ounce Aquamira water treatment refills. You'll need the original dropper bottles to get proper measurements.
One package of Aquamira treats 30 gallons of water and should be adequate treatment for any long backpacking trip. If you're hiking the PCT or AT, you may need to send yourself a new package along the way.
Adding water Treatment Drops and mixing caps lined up with the premixed parts A and B, waiting the required five minutes before adding to water.
The initial activation of the liquids requires waiting five minutes. Once you add this mixture to your water, wait another 30 minutes to an hour for it to sterilize.
You have to make the call if you're worried about viruses in the water or not - if you are traveling in Canada or the U.S., you shouldn't have to worry about this. This method is not as fast as a gravity-fed filter such as the Platypus GravityWorks, our Editors' Choice winner, but it does eliminate viruses as well, which the GravityWorks does not.
This system consists of two single ounce bottles, with the mixing caps weighing about three ounces. For shorter trips, the liquids can be decanted into smaller bottles to make for an even lighter system. Except for only carrying one or two of the MSR Aquatabs, this would be the lightest system and is the most popular system for thru-hikers because it is so lightweight and also inexpensive. Waiting an hour can be a drag, but you do have the option of waiting for less time if you are only concerned about certain organisms. If you're looking for a fast, lightweight option for day trips like big trail runs we recommend the Lifestraw Flex for instant drinking water in a small package.
This method is prevalent among long-distance hikers and is even advocated by NOLS instructors because of its light weight, ease of use, and effectiveness. It is much less bulky than a filter and has the added benefit of eliminating viruses; this is the best method for weight-conscious hikers. If you are planning to be in an area where there is a lot of silt in the water, consider bringing a more traditional filter like the Katadyn Hiker Pro Microfilter or a gravity filter like the Katadyn Gravity Camp.
Filling water in a stream along the Appalachian Trail before purifying.
If you are on a seriously small budget, and the initial price of a filtration system ($85-$350) is setting you back, a chlorine dioxide treatment such as this would be the least expensive option, which is one reason we give it our Top Pick award. The cost of $14.95 for two 1-ounce bottles will treat 30 gallons, or if you break it down, it averages to around 13 cents per liter treated. You can also get the larger, 2-ounce refill bottles for $16.99.
The Aquamira Treatment Drops receives our Top Pick Award because it is super lightweight at three ounces and is the most versatile chemical treatment in this review. It is a great value choice and can treat anywhere from one to 100 liters at a time, depending on the need. Although it takes longer than a speedy gravity filter like the MSR AutoFlow Gravity Filter, it is much lighter, inexpensive, and it treats viruses - if you are willing to wait the full four hours. Toss it in your pack for day hikes where you'll need a refill or long through hikes. It also works well as a backup purifier if your primary filter fails on you.