Keep in mind; most of the homes filtering systems out there are designed to remove chemicals (lead, copper, chlorine, etc.). They work on the premise that the water is already safe to drink from a microbiological point of view. Generally, individuals out in the "field"; filter water to remove/reduce microbiological contamination. Most pump systems work by "trapping" organisms within the filter proper and the ability to remove certain organisms is based upon the micron size of the organism and the micron size of the filter. Some have an added chemical component (i.e. iodine or silver) to kill viruses, since these are not removed/killed by the filtering process. The water bottle filter I mentioned does have such a component, I think it is silver, to kill viruses and is an EPA registered water filtration device. Pete