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What To Look For
When evaluating water filters for your hiking needs, pay attention to their pore size, replacement frequency, weight, efficiency, availability, value, endurance, reliability and chemical treatment method (if offered). Pore size determines how effectively a filter will eliminate bacteria, protozoa and parasites. A pore size of .2 microns meets EPA drinking water standards; .02 microns is as good as it gets. The most efficient filters produce more clean water with less effort. The MSR Hyperflow Microfilter wins this contest hands down, with its filtration rate of 3 liters per minute. Katadyn ceramic filters are the leaders in endurance and reliability. They last at least 10 times as long as other filters.
Common Pitfalls
If you need to use your filter for winter camping, or in extreme conditions, avoid ones with plastic bodies. Some, like the MSR Hyperflow Microfilter, can be broken if dropped and are likely to malfunction in below freezing temperatures. If you use purification tablets or drops to add virus protection to your filter, avoid products that contain iodine, as it won't neutralize cryptosporidium. A better choice is chlorine dioxide, which effectively kills all bacteria, protozoa and viruses.
Where To Buy
The best deals on any given water filter or purifier generally can be found on eBay. Look for power sellers with a lot of positive feedback. REI is also a great place to shop for filters; they have a good inventory of the top-rated units and annual cash-back rewards for members. Keep an eye out for summer sales.
At http://www10.epinions.com/ you can quickly compare prices and read user reviews to help you decide what to get and where to get it. Other price search engines can be found at http://www.streetprices.com and http://www.pricegrabber.com.
Cost
The MSR Miniworks EX is the most popular backpacking water filter and it's available for $60 to $80. Replacement filters run about $40. The Katadyn Pocket Filter is built to last forever and it's backed by a 20-year warranty. You can pick one up for $140 to $220 and you'll never need to replace the filter. The innovative Hydro-Photon SteriPEN Adventurer uses an ultraviolet light to kill bacteria, protozoa and viruses without pumping or filter cleaning. It's available for $70 to $100.
