Certification

One of the main things to consider when purchasing a drinking water filtration system is the contaminants it will remove.  There are literally thousands of water filters (some with fairly elaborate claims) on the market today made by hundreds of companies.  A company can say anything in its literature or on its web site, and how can you evaluate the claims to determine if they are true - do you believe the company's lab reports, the glowing testimonials on their web site?  The Information may be accurate, but HOW CAN YOU KNOW?

Certification by an independent third party like NSF International (and now UL - the same company that certifies your toaster or lamp) is the best way of identifying those water filters that some group (besides the manufacturer) has reviewed and determined to perform as advertise.  There are two ANSI/NSF standards that pertain to drinking water filtration systems: Standard 42 for Aesthetics Effects (cosmetic factors like taste, odor, chlorine, and particulate reduction) and Standard 53 for Health Effects (the contaminants that are harmful to health).

There are even a few pitfalls to interpreting the certification reports - one of the things to be aware of is what I call "padding the list".

For example, below are three contaminant reduction lists from NSF International.  They are 3 of the 12 companies listed when ‘MTBE reduction’ was checked on the search engine at the NSF International site under the category “Reduction Claims for Drinking Water Treatment Units - Health Effects”
http://www.nsf.org/Certified/DWTU/

Below is an illustration of the way some companies “play the certification game” by 'padding the list' to make their 
contaminant list appear longer than other companies.  They pay separately to have individual VOCs tested and listed,
even though, if the VOC Reduction group is listed, all of the individual VOCs on the NSF table below are already covered 
and do not need to be re-listed.

In the lists below, contaminants that are VOCs are identified (VOC- ), and those contaminants that are not in the NSF International VOC list are shown bolded.

Other important considerations when evaluating and selecting a water filtration system that you plan to use for many years are:

Pore size of the filter media - smaller is better.  Smaller particulates are removed, and water comes into contact with more of the filter media (the activated carbon).
Solid Block Activated Carbon (SBAC) or Granular Activated Carbon (GAC).  SBAC is more effective for a given size of filter cartridge and at a given flow rate than a GAC filter.  GAC filters also have large pores that let more contaminants pass through, because all of the water may not contact the filter media.
Physical size and capacity.  All other things being equal, a larger filter will be more effective removing contaminants at a given flow rate than a smaller filter.  Filter effectiveness depends on the water's contact time with the filter media - a larger filter allows the water to have more contact time.  Smaller filters must also be changed more frequently than large filters, and they do not do as good a job during their rated life.
Long term cost of replacing the filter cartridges.  Some of the smaller filters may be less expensive individually than a large filter, but when several years of filter replacement are considered, the larger filtration system may be more economical.
Construction materials of the filter housing.  Some filters are light weight plastic that will need to be replaced every few years.  Other filters are heavy gauge stainless steel and will last a life-time.
Warranty and the length of time the company has been in the water filter business.  If you do invest in a more expensive, high-end filtration system, you want some assurance that when you want to replace the filter cartridge in 20 years the company will still be in business.  There are no absolute guarantees, of course, but a company that has already been in business for many years at least has an established track record.

Contaminants listed under ANSI/NSF Standard 53 for Health Effects on the NSF International web site:

P__   VOC- 2,4-D Reduction   VOC- 2,4,5-TP Reduction   VOC- Alachlor Reduction Asbestos Reduction   VOC- Atrazine Reduction   VOC- Benzene Reduction   VOC- Carbofuran Reduction   VOC- Carbon Tetrachloride Reduction Chlordane Reduction   VOC- Chlorobenzene Reduction Cyst Reduction   VOC- Endrin Reduction   VOC- Ethylbenzene Reduction   VOC- Heptachlor Epoxide Reduction Lead Reduction   VOC- Lindane Reduction Mercury Reduction   VOC- Methoxychlor Reduction MTBE Reduction   VOC- O-Dichlorobenzene Reduction   VOC- Simazine Reduction   VOC- Styrene Reduction   VOC- Tetrachloroethylene Reduction   VOC- Toluene Reduction Toxaphene Reduction TTHM Reduction   VOC- Trichloroethylene Reduction Turbidity Reduction

A__   VOC- Alachlor Reduction Asbestos Reduction   VOC- Atrazine Reduction Chlordane Reduction Cyst Reduction   VOC- Ethylene Dibromide Reduction   VOC- Dibromochloropropane Reduction   VOC- Heptachlor Epoxide Reduction Lead Reduction   VOC- Lindane Reduction Mercury Reduction   VOC- Methoxychlor Reduction MTBE Reduction PCB Reduction Toxaphene Reduction TTHM Reduction Turbidity Reduction VOC Reduction   VOC- Xylenes Reduction   VOC- 2,4-D Reduction   VOC- 2,4,5-TP Reduction

M-P__ Asbestos Reduction Chlordane Reduction Cyst Reduction Lead Reduction Mercury Reduction MTBE Reduction PCB Reduction Toxaphene Reduction TTHM Reduction Turbidity Reduction VOC Reduction

NSF International Volatile Organic Chemicals (VOC) list:

The VOCs that have been counted in the lists above have been highlighted. 

alachlor                     atrazine                     benzene                      carbofuran                   carbon tetrachloride         chlorobenzene                chloropicrin                 2,4-D                         dibromochloropropane (DBCP)   o-dichlorobenzene            p-dichlorobenzene             1,2-dichloroethane           1,1-dichloroethylene         cis-1,2-dichloroethylene     trans-1,2-dichloroethylene

1,2-dichloropropane         cis-1,3-dichloropropylene   dinoseb                     endrin                      ethylbenzene                ethylene dibromide (EDB)    haloacetonitriles           haloketones                 heptachlor                  heptachlor epoxide          hexachlorobutadiene         hexachlorocyclopentadiene   lindane                     methoxychlor                 pentachlorophenol

simazine    styrene   1,1,2,2-tetrachloroethane   tetrachloroethylene   toluene   2,4,5-TP(silvex)   tribromoacetic acid   1,2,4-trichlorobenzene   1,1,1-trichloroethane   1,1,2-trichloroethane   trichloroethylene   trihalomethanes (TTHM)   xylenes

 Close this screen to return to the previous page.