The importance of independent certification for product evaluation - Truth in advertising:

There are many thousands products on the market that claim to provide you, the consumer, with purest water available, everything from filtration systems and distillation units to bottled water.  There are, for example, over 2,500 different water filters on the market.  

How do you evaluate competing, often contradictory, statements and determine which claims are accurate and which advertisements are nothing more than creative writing.  When purchasing health related products, creative advertising can be expensive for the consumer, not to mention downright dangerous.  An improperly maintained water filter can actually incubate trapped bacteria and release them into the "filtered" water.  

I personally believe that a product's performance as well as the accuracy of its advertising literature should be tested and certified by an independent and disinterested third party.  If a product is certified by a reputable company you can be assured that a product's ads are not misleading and the product will perform as specified.

Two organizations provide independent certification for water purification devices, NSF International and the Water Quality Association (WQA).  Underwriters Laboratories (UL) is also beginning to certify water treatment systems.

The WQA has developed a Gold Seal program to help consumers choose quality water treatment products.  The WQA tests prototype water treatment equipment, and awards the Gold Seal only to those systems that have met or exceeded industry standards for contaminant reduction performance, structural integrity, and materials safety.

NSF International is a group that certifies water treatment systems, distillation units, bottled water, water softeners, and a number of other food preparation systems.  NSF certification means that not only do the products perform as tested, the product advertisements are also evaluated for accuracy and truthfulness.  Products are tested on an ongoing basis to make certain that companies continue to produce products that perform as advertised.  

You need to be aware that there are a number of different NSF standards and different levels of compliance within the standards. NSF certification does not mean much unless you know exactly what  a specific certification standard stands for. A water filter certified to meet NSF Standard 42 Class II for taste, odor and chlorine and Class II for particulate matter is not equivalent to a filter certified to meet NSF Standard 42 Class I for taste, odor and chlorine and Class I for particulate matter and Standard No. 53 for Health Effects.  The latter filter will remove a far wider range of contaminants -- and will also probably cost 10 times as much as the former.  

You will also find, if you research water purification devices or bottled water, that many companies state on their literature "Tested to NSF standards".  Tested by who?  How often?  Who backs up that claim?  I just visited a web site that advertised their water filter as tested and certified in accordance with NSF/ANSI standards 42 and 53 (the NSF logo was even displayed).  I then checked the NSF on-line site and neither the company nor the filter was listed as certified. 

NSF International Mission statement - Behind the NSF Mark is an independent, not-for-profit organization called NSF International. For over 50 years NSF has been committed to public health safety and protection of the environment by developing standards, by providing education and by providing third-party conformity assessment services while representing the interest of all stakeholders.  The NSF site provides an on-line comparison of water filtration units and bottled water products that are certified by NSF. NSF Video: Choosing a Drinking Water Treatment Unit You can review certified Drinking Water Treatment Units.     The NSF Standards that apply to water filters are # 42 and      # 53. To use the guide, for water treatment units, either enter     a company name you are interested in investigating or scroll     to the bottom of the page and select either the product type     (counter top filter, under counter filter, etc.) or the product     standard (42, 44, 53, etc.).     You can look up certified bottled water products by brand     name, product type, etc. at Bottled Water and Packaged Ice. NSF Drinking Water Standards There are currently six ANSI/NSF standards relating to water filtration and treatment devices, each one designed for a specific type of product.    STANDARD 42: Drinking Water Treatment Devices - Aesthetic Effects    STANDARD 44: Cation Exchange Water Softeners    STANDARD 53: Drinking Water Treatment Devices - Health Effects    STANDARD 55: Ultraviolet Microbiological Water Treatment Systems    STANDARD 58: Reverse Osmosis Drinking Water Treatment Systems    STANDARD 62: Drinking Water Distillation Systems