WILDERNESS campers are well aware that backcountry travel necessitates some discomfort, even when it comes to drinking water. For years, they bungled with slow, cumbersome filters and endured the flavor of iodine. But in recent years, new water-treatment products have made it simpler to treat water in the wild, while making the water itself tastier.

''Filters have gotten much, much, much easier to operate, and you get greater flow rates,'' said Frank Kosco, the water-treatment product buyer at Campmor, an outdoor-equipment retailer. ''The resistance on the pump isn't as tough as it used to be, and you get longer life from the filters.''

The problem is that water from rivers, lakes and streams may look clear and potable, but still may contain parasites, viruses and bacteria. Boiling the water is time-consuming and does not filter out grit, while the age-old pump-style filter can be slow and clunky. The latest products include gravity-fed filters, chemical purifiers and ultraviolet-light systems, which Mr. Kosco said added up to ''less work and less aftertaste'' than older modes of water treatment.

Laura Steinbach, left, a backpacking guide with Southern Yosemite Mountain Guides, tested five water-treatment systems in Yosemite National Park. All five kill bacteria and protozoa (like giardia and cryptosporidium) found in North America and are suitable for backcountry use on this continent. Three -- the SteriPEN JourneyLCD, Katadyn Micropur tablets and PUR Clean Drinking Water Kit -- also kill viruses more commonly found in less developed countries. KATE SIBER

PHOTOS: MSR HYPERFLOW MICROFILTER,: $99.95, cascadedesigns.com. Ms. Steinbach found this filter, left, easy to use, despite directions that weren't very clear. ''I had a 3-year-old pumping it while I held it,'' she said. One drawback is that the ''prefilter'' -- which removes larger sediment before the fine filter -- ''tends to flip over when in standing water,'' she said. But she said it filtered a liter of water in less than one minute.; PUR CLEAN DRINKING WATER KIT,: $28.99, purpurifierofwater.com. This packet of treatment chemicals, above, ''requires multiple steps, multiple containers and five minutes of vigorous stirring,'' Ms. Steinbach said. ''It's labor-intensive and it takes a long time.'' Though the packet of chemicals was small, she found the 2.5-gallon containers, which held the minimum amount of water needed for one packet, ''bulky even when compressed.'' She added, ''If it's Hurricane Katrina and you have to treat a lot of water for a lot of people, it would be great,'' she said, but it was impractical for backcountry use.; STERIPEN JOURNEYLCD HANDHELD WATER PURIFIER,: $99.95, steripen.com. This compact, 4.5-ounce ''pen,'' below, zaps water with UV light for 90 seconds, killing bacteria, protozoa and viruses. Ms. Steinbach appreciated that it was lightweight, ''simple to use'' and left no aftertaste. One drawback, she said, was that ''the pen itself does not remove sediments,'' which means that ''you must carry a separate strainer, available for purchase, for the removal of particulates.''; KATADYN MICROPUR MP1 PURIFICATION TABLETS,: $9.95 for a package of 20, katadyn.com. This treatment was ''easy -- drop it in and wait,'' Ms. Steinbach said. The minimum wait was 30 minutes, though in areas where people suspect extremely contaminated water, the company recommends waiting four hours. Because the tablets weigh so little, Ms. Steinbach believed this system of treatment would appeal to weightconscious backpackers. The tablets added no extra taste, but they didn't remove sediments and turned the water yellowish.; SAWYER 2 LITER COMPLETE WATER FILTRATION SYSTEM,: $89.95, sawyerproducts.com. This filter is designed to hang on a tree and let gravity work: water travels from a nylon bag through a tube filter and into another nylon bag. There was ''no pumping or extra filtering necessary,'' Ms. Steinbach said, and it took less than three minutes to filter two liters of water, which is ''pretty quick.'' She said it would have been more convenient if the kit had a valve ''for dispensing water into individual water containers'' and for drinking.(PHOTOGRAPHS BY GARY KAZANJIAN FOR THE NEW YORK TIMES)