| Water Filter Comparison is greatly simplified by the | | | | Water Treatment Systems. This sets standards |
| process of certification. Of the three organizations | | | | relates to the destruction of microorganisms in water. |
| that are officially approved for certifying water | | | | There are two classes of UV systems: Class A is |
| filters, The NSF International is the best know. They, | | | | designed to disinfect and remove microorganisms, |
| along with the American National Standards Institute | | | | such as bacteria and viruses, from contaminated |
| (ANSI) have established the following standards for | | | | water to a safe level. Class B is a system designed |
| evaluating and certifying drinking water treatment | | | | to supplement bactericidal treatment of public drinking |
| units: | | | | water or other drinking water which has been |
| NSF/ANSI Standard 42: Drinking Water Treatment | | | | deemed acceptable by a local health agency. |
| Units - Aesthetic Effects. This certifies that the filter | | | | NSF/ANSI Standard 62: Drinking Water Distillation |
| reduces the non-health related contaminants such as | | | | Systems. This standard is designed specifically for |
| chlorine and other tastes and smells to a specific | | | | distillation systems verifying the reduction of specific |
| level. | | | | contaminants such as total arsenic, chromium, |
| NSF/ANSI Standard 53: Drinking Water Treatment | | | | mercury, nitrate/nitrite, and microorganisms from |
| Units - Health Effects. This standard addresses the | | | | public and private water. |
| effective reduction of a long list of health related | | | | NSF/ANSI Standard 177: Shower Filtration System - |
| contaminants such as Cryptosporidium, Giardia, lead, | | | | Aesthetic Effects. This certifies the reduction through |
| volatile organic chemicals, etc. | | | | a shower filter of free available chlorine that may be |
| NSF/ANSI Standard 58: Reverse Osmosis Drinking | | | | present in the water. |
| Water Treatment Systems. Standard 58 is designed | | | | If you are doing a water filter comparison to |
| particularly for RO systems to verify reduction of the | | | | determine which filter is the best for you, it makes |
| kinds of contaminants they remove such as fluoride, | | | | sense to verify if that filter is certified and by whom. |
| hexavalent and trivalent chromium, total dissolved | | | | NSF has a useful tool on their website for verifying |
| solids, nitrates, etc. | | | | whether or not a given filter is certified entitled |
| NSF/ANSI Standard 44: Cation Exchange Water | | | | "Product and Service Listings". It will tell you under |
| Softeners. This standard verifies the filter's ability to | | | | which standard the filter is certified and for the |
| reduce hardness in the water and can verify its ability | | | | removal of which contaminants. |
| to reduce radium and barium. | | | | For a fuller understanding of the complexities of |
| NSF/ANSI Standard 55: Ultraviolet Microbiological | | | | certification check out the free report cited below. |