What's the difference between a water filter and a water purifier?

There are two different standards in the water filter industry for classifying water treatment devices.

A water filter must remove at least 99.99% of pathogenic bacteria. This is known as a log 4 reduction.

A water purifier must remove at least 99.9999% of pathogenic bacteria (log 6 reduction). Additionly the water purifier must be capable of reducing viruses by at least 99.999% (log 5 reduction)

All Berkey systems containing the Black Berkey purification elements are classified as Water Purifiers. Berkey Water Purifiers go beyond the water filter industry standard and attain a 99.9999999% (log 9 reduction) removal of pathogenic bacteria. To the best of our knowledge no other water filtration/purification device in the world can match this claim.

Since most people search for water filter or purification systems on the internet with search terms such as water filter, water filters or water filtration, we use the terms filter/filtration and purifier/purification interchangeably on our website with respect to the Berkey Water Purification Systems and the Black Berkey purification elements. Anytime we use the term filter/filtration in respect to the Black Berkey purification elements or Berkey Water Purification Systems we are always actually signifying purifier/purification.