A portable device for filtering and purifying water comprised of an outer chamber and an inner chamber that is slidable within a section of the outer chamber, and a small pore size pre-filter, whereby water is drawn through the pre-filter into the first container section of the outer chamber where it is isolated and treated with a disinfectant agent, then is drawn out of the first container section and into the second container section, and then into the inner chamber, where it is passed across another filtering material such as an activated carbon bed, removing any remaining contaminants before the potable water exits through a mouthpiece.