To date, no independent research group, including government agencies or universities has performed a comprehensive scientific analysis and comparison of the microfilters and purifiers that are currently available. Because of this knowledge vacuum, the best that purchasers can do in choosing a device is to apply the knowledge of the risks and the EPA testing protocol to manufacturers’ literature and come to their own conclusions.
While we recommend our preferred treatment method in the next section, we won’t recommend a specific product, however, we can recommend a procedure for selecting a treatment device. While reading these recommendations, remember to keep in mind the EPA log reduction standards and the weaknesses in the EPA tests.
- Assess your needs in terms of the volume of water you will need to pump, size and weight of devices and the cost and availability of devices and replacement filters.
- After selecting devices that might meet your needs assess manufacturers’ promotional material and examine them carefully for claims and evidence. Be very skeptical and watch for extraordinary requirements such as slow pumping rates, wait times, the need to pass water through the device several times and other possible red flags that are often tucked away in fine print and footnotes. Ask for EPA registration numbers and results from EPA lab tests. If manufacturers will not send you lab results you should be suspicious.
- Determine the cost effectiveness of products by looking at the initial upfront cost and the cost of replacement filter elements. Be skeptical of manufacturer claims about filter life if the conditions under which the lifespan is determined are unknown or unrealistic. Remember that the more suspended silt and vegetation in the water, the faster a filter will plug. Consider whether the filter can be cleaned or back flushed if it clogs or whether you need to replace it. If you have to replace filter cartridges, find out how much they cost, consider whether you will be able to find them while travelling and consider the environmental cost of throw away filter cartridges versus cleanable filter elements.
- Once you have narrowed your search down to a few products that seem to fulfill your needs if possible examine the devices in a store. Look for signs of quality construction and compare warranties. Obvious weaknesses in design are guaranteed to cause headaches at the worst possible times. If parts look flimsy in the store, image how they will look broken in pieces 30 km down the trail. Consider usability and field maintainability.
- Research the manufacturer. Find out how long they have been in business and their reputation in the water treatment business. Ask for references to find out who uses their products and what the users think of the products. For example, a company that supplies the International Red Cross or United Nations workers certainly has more credibility than a company that cannot, or will not, give you a reference.