A pur water filter is not to be confused with water purifiers. Water purifiers have higher standards and may even remove viruses, which are quite often impossible for most kinds of water filters to remove. Water purifiers use more than just filtration to remove contaminants and may use UV light, deionization, water softening, reverse osmosis, and other methods of purification in addition to filtration. Water bottling companies for instance do not use just a  pur water filter  but a water purifier that often will employ several purification stages other than just filtration.