To Your Health

Q. A friend and I will take an extended hiking/camping vacation this fall, and I am looking for a way to get safe water on the trip without carrying it along or spending a lot of money for a water purifier. What are the options?

A. Heat, filtration, chemical treatment, or some combination of these are the usual ways to disinfect water on a hike and make it safe to drink. The best method for you will depend on several factors: cost, the distance you will hike, the sanitation of the water available on your route, the amount of water needed, and the size/weight of the purifying equipment and ease of its use. You will probably have several inexpensive options and several more options if you want to invest a modest amount of money. Keep in mind that you can also ask oncoming hikers on the trail about water and what else lies ahead.

Survivalists can point out methods of water purification that cost little or no money but will take some time to work. You might want to know about some of these "tricks" for backup to your first choice of a purification method. For instance, putting water in used soft-drink bottles and setting them out in the hot sun for several hours will kill most microbes. Kenyan children who treated water this way suffered diarrhea 20% to 30% less often than did those who drank from bottles they left in the shade. Another ploy is to dig a hole a few yards from a stagnant pool. In a few hours it should fill with water that is relatively free of contaminants.

Chlorine is a standard agent for purifying water, but the chemical reaction of chlorine with organic material in water can produce worrisome, even carcinogenic compounds. Everyone agrees that the risk from these toxic substances is still less than the risk of diarrhea from untreated water. Even this risk can be reduced if the chlorine-treated water is filtered through a small charcoal filter.

Boiling water for at least 15 minutes will kill most bacteria but will not remove many of the other chemical contaminants or improve the taste. Another problem is that fuel may be hard to obtain or may pose an environmental hazard. A solar still will purify water for you, converting even the murkiest swamp water into almost 100% pure, drinkable water. The apparatus will collect only a few pints of water per day, which may not be enough for two active people.

For about $80 (or half that if you find a used one) a high tech water purifier that makes a gallon per minute of pure water can be found in sporting-goods stores. It uses no chlorine or iodine (which work but impart a distinct taste) but instead uses a proprietary "structured matrix" filter to remove even viruses. It gets high marks from experienced hikers and is certainly worth the investment if you plan to use it for several years.

Don't be fooled by a clear, cold stream along the trail that you may run across. Any water found in the outdoors, even the freshest-looking bubbling brook, can be contaminated with any number of diseases that are carried by either humans or animals. Treat all drinking water on your trip, and you should make the trip comfortably.