People often make the mistake of taking a water purifier for a water filter, though the two items have certain things in common, they are nevertheless two distinct items. While both remove bacteria by using a mechanical force for pumping water through a screening device, only a water purifier has the necessary features to render the micro-organisms in the water inactive. There are two ways to complete the inactivation: either by chemical or by electrostatic procedures. The use of a water purifier is necessary even for waters in the wild that are considered relatively safe; they may still contain some micro-organisms that could endanger human health.