Berkey Natural Purification Systems are the World’s Most Powerful and Economical Personal Water Purification Systems – Providing Reliable and User-friendly Water Purification in Both Normal and Hostile Filtration Environments. Moreover, Berkey systems are capable of purifying both treated water and untreated raw water from such sources as remote lakes, streams, stagnant ponds and water supplies in foreign countries, where regulations may be substandard at best. A Berkey is perfect for everyday use and is conveniently portable for use in camping or any environment where electricity, water pressure and/or treated water may not be available.  Berkey’s are popular with families and communities that practice  emergency preparedness.