Interest in home water treatment products such as Berkey filters has grown tremendously over the past 15 years. Unfortunately, it isn't always easy for consumers to know whether or not a particular product will actually be as safe and effective as the manufacturer claims at reducing various contaminants from your water supply. This is where the NSF, a international public health and safety company, plays a critical role.
The NSF (National Sanitation Foundation), headquartered in Ann Arbor, Michigan, is an independent testing laboratory that performs comprehensive testing and certification of filtration products. In order for a product to earn "certification" for reduction of a contaminant, it must be able to reduce a specific amount of that contaminant. Certification is voluntary, so it is important that the consumer ensures that the product they are considering purchasing has attained certification.
One critical filter feature that sometimes gets overlooked is the level to which the filter removes contaminants from the water. For carbon filters, focusing on the pore size has some value, but the most important statistic is at what degree this filtering occurs. For instance, there is a significant distinction between water filters and water purifiers. A water filter like the ceramic berkey filters must remove pathogenic bacteria at the 99.99% level, also known as log 4. On the other hand, a water purifier like the black berkey elements, must be able to demonstrate a 99.99999% reduction in pathogenic bacteria, known as log 7. This is a much stricter standard and NSF certification in this regard gives confidence to the consumer that they are getting a high quality water purifier. If you are interested in water purification, double check to make sure the manufacturer and/or seller is not just throwing the word "purifier" around as it does have technical significance.
As a general rule, look for filters labeled as meeting NSF/ANSI standard 53. This standard applies to point-of-use (POU) and point-of-entry (POE) systems with a focus on removing bad tastes, odors, and chlorine. Standard 53 certified filters substantially reduce many hazardous contaminants, including heavy metals such as copper, lead and mercury, disinfection byproducts, parasites such as Giardia and Cryptosporidium, pesticides, radon, and volatile organic chemicals such as methyl-tert-butyl ether (MTBE), dichlorobenzene and trichloroethylene (TCE). For those interested, Berkey also has a separate class of filters called pf-2's that filter out arsenic and fluoride.
Don't forget that no filter will give you good performance over the long term unless it receives regular maintenance. As contaminants build up, a filter can become less effective and actually can make your water worse by starting to release harmful bacteria or chemicals back into your filtered water. The more contaminated the water, the more often you should clean the filters. Happy filter shopping!
The Thirsty Berkey - For the Love of Clean Water