 As a result, the U.S. Environmental Protection Agency has accepted UV disinfection as a method for drinking water plants to obtain cryptosporidium, giardia or virus inactivation credits.For example, for a 90% reduction of cryptosporidium, a minimum dose of 2,500 μW·s/cm2 is required based on the U.S. EPA UV Guidance Manual published in 2006.UV water treatment devices can be used for well water and surface water disinfection.