JOSEPH ON FLICKR/CREATIVE COMMONS 2.0<br />A hiker refills her gravity system, one of several effective methods for backcountry water treatment.

If you’ve ever squatted awkwardly by a stream with a pump-operated water filter in hand, you know the drill: wayward hose, wobbly bottle, muscle-clenching workout. Maybe it’s time to try one of the other water-treatment methods that have proliferated in recent years.

But first, you have to know your enemies. The biggest risk in the backcountry is Giardia, a tiny critter that wreaks gastrointestinal havoc from inside your gut. Other baddies include Cryptosporidia and various viruses. “Crypto” is rare but even worse than Giardia if you acquire it, while viruses, essentially nonexistent in the North American wilderness, can be a real concern for international travel.

All of the options below remove or kill Giardia and crypto, as well as any additional protozoa or bacteria in the water. Viruses, which are too small to be captured by filter systems, can only be eliminated by chemical treatment or UV light.

Harness Gravity

This method is simple and relatively quick: A hose connects two bags, one of which is elevated above the other. Untreated water flows from the upper bag, through an attached filter, then collects once clean in the lower bag.

A gravity system is a good choice for large groups, as most treat between 2 and 4 liters per fill at roughly 1 to 1.5 liters per minute with a clean filter. These systems run $80 to $140 and weigh 10 to 16 ounces. One of the best is Platypus GravityWorks.

Gravity filters are less than ideal when it comes to collecting water from shallow sources and in open terrain, where there’s no easy way to hang one bag higher than the second—other than holding them aloft.

Beam UV Light

Ninety seconds of ultraviolet (UV) light kills everything in 1 liter of water, no pump or gravity required. Insert the UV bulb into the water bottle, turn it on, stir, and your water is ready soon after. Ultralight options include the SteriPen and the CamelBak All Clear Water Purifier which integrates the UV system into the bottle cap.

This method relies on battery-powered devices, which means an increased risk of failure, and it doesn’t remove sediment or grit.

Unleash Chemicals

Chlorine and iodine can kill all of your microscopic nemeses. Simply add drops or tablets to your water bottle and let it sit. There’s no lighter or more compact method. Two time-tested options are the chlorine-based Aquamira drops and the iodine-based Potable Aqua tablets.

There are some significant drawbacks. First is the wait time: a minimum of 15 minutes to kill giardia and four hours for crypto. Chemical treatments also leave sediment behind, and may have a distinct flavor.

Slurp via Filter

Maybe you’d rather drink directly from a source—or from previously untreated water stored in your water bottle—via an ultralight filter. Options include the LifeStraw, a long, skinny design, and the Sawyer Mini-Filter, a somewhat squatter option. At a paltry 2 ounces each, both remove sediment but require constant use whenever you drink.

Keep on Pumping

Or stick with the tried-and-true pump. With this setup, repetitive pumping pulls water up an intake hose, through an internal filter, and into your container. Reliable models range from 8 to 16 ounces for $75 to $100 and include the MSR SweetWater and the Katadyn Hiker Pro.

These are relatively bulky, somewhat awkward, and require maintenance, but they also provide clear, sediment-free water. Bonus: The small intake hose makes these best for shallow water sources. Bottom’s up!