A. If your water filter is not minimally certified to meet NSF standards 42 & 53, you do not want it because it does not provide you with “reasonable assurance” that the water filter is doing what it is supposed to do. Often name brand water filters are not certified by NSF to meet standard 42 and 53 even though some may give the distinct impression that they do. For example, water filters that say they are “independently tested” to meet NSF standards 42 and 53 does not mean that they were actually tested and certified by the National Science Foundation (NSF). This marketing deception is sometimes carried out by unscrupulous water filter manufacturers who give consumers the false impression that NSF actually performed these tests, hiding the fact that the tests were conducted by a laboratory that the company hired. The only way to know if a water filter was tested and certified by NSF is to visit www.nsf.org and enter the product name in the section entitled ‘Search Certified Products & Systems’ to obtain a listing and confirmation of certification. Many times claims made by manufacturers cannot be ascertained on NSF website. This happens often because the industry is not regulated.