Not a Drop to Drink?

These water-purification systems will ban nasty bacteria from your bottle.

By Stephen Regenold
Photographs by John R. Fulton Jr.

They swim and float in water, undetectable and unseen. They breed and multiply and search for a host. With sinister names, microbes like giardia and cryptosporidium can wreck a wilderness trip quicker than you can shout, “Where’s the latrine?”

But fear not. Outdoors types can combat bacteria, viruses, and protozoa via a litany of purification products available at any outdoors shop.

Water-purification tablets, pumps, filters, and UV-light mechanisms kill the tiny creatures that can make you ill. A few minutes of pumping—or the zap of light from a UV pen—might make the difference between getting sick and staying healthy.

Muddy creeks and reedy shores are immediately suspect for water that could be bad. But to be safest, experts recommend treating any water taken outdoors before you fill your cup. “Even the most pristine areas are subject to a host of environmental conditions or pollutants that cannot be detected by sight, smell, or taste,” says Frank Reigelman, the Boy Scouts’ Outdoor Programs team leader.

The five products below filter and purify water by various means. For wilderness trips, where protozoa and bacteria are main concerns, pumps and filters will work fine. For maximum protection, especially when near human development, look to one that neutralizes all biological contaminants, including viruses.

Final point: The old-fashioned trick of boiling water on a campfire is a foolproof—and effective—purification plan. Plus, it’s essentially free.

Outdoors writer Stephen Regenold is founder of


Pump it! The HyperFlow provides a fast way to purify water in the backcountry, including a filtration rate of three liters per minute. At about seven ounces, the unit is lightweight enough for backpacking. It connects via a bottle adapter to a variety of containers, and it’s designed to be cleaned in the field. MSR markets the HyperFlow as effective against all protozoa and bacteria but not viruses.


Zap the bugs! SteriPEN employs a unique ultraviolet-light mechanism to expunge biological contaminants—bacteria, protozoa, and viruses included. Dip the light in your water and let it shine for 90 seconds. Now the water is clean. It weighs just 3.6 ounces with batteries, making the package light enough for any pursuit. One warning: The SteriPEN does not work with cloudy water. Pre-filter murky water before zapping it with the UV light.


$9.95 for 20 tablets
Inexpensive, lightweight, and easy to use. Drop a Micropur tablet into a quart of water, let it dissolve, and your water will soon be ready to drink. These chlorine dioxide tablets are the same ones that Philmont Scout Ranch sends out with crews each summer. In 30 minutes, the tablets eliminate viruses and bacteria. One bummer: Cryptosporidium, a nasty contaminant found in some areas, takes four hours to neutralize.


Dip this 24-ounce bottle in water, screw the cap and purification system back on, and squeeze the bottle to purify and drink in one motion. That’s the simplicity of Katadyn’s MyBottle, a common bike bottle with a built-in filter. The bottle’s filter eliminates viruses, bacteria, and cysts. Bonus: It has a carbon cartridge to neutralize water and nix the not-so-pleasant swampy aftertaste you might get with a wilderness drink.


Touting “no moving parts, no assembly, and near-zero effort,” the CleanStream is a unique filter for in-camp use. Hang it up and let gravity do the work. Water trickles from one reservoir to the other, passing through a filter for purification along the way. It can handle four liters of water every 2.5 minutes, making it fast and easy. Like the MSR pump, the CleanStream handles all protozoa and bacteria, but not viruses, making it suitable for wilderness use.

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