But filtering water does not automatically purify it. This includes some bacteria and protozoa as well. Purification is a combination of filtering and disinfecting. It involves actually killing any bacteria, protozoa and viruses in the water. Disinfecting water is accomplished by using chemicals or boiling water.
Water filters are very simple to use, but employ a very intricate design.
As the water passes through the filter, small particles are trapped within the interior surface of the filter. The surfaces are made of ceramic, glass fiber or other porous material which needs to be cleaned periodically, depending on the amount of use. Some water filters also come with a membrane as a backup to ensure maximum filtration. Different pore sizes in both the membrane and the interior surface are available, depending on how much you are willing to spend. Cheaper water filters often have larger pores, which obviously let larger particles through.