Many of those who evaluate water filters, like Consumer Reports and Natural Resources Defense Council, recommend that you purchase an NSF certified water filter. I wonder if these organizations actually know what the certification process involves. If they did, I think they’d be disappointed. The certification does not necessarily mean what you, the consumer, are lead to believe…
Here’s a definition of one of the most common certifications for whole house water filters intended to remove chlorine:
‘NSF/ANSI 42: Drinking Water Treatment Units, Aesthetic Effects
This section of the directory lists those drinking water treatment units which have been WQA certified in accordance with “Voluntary Industry Standard For Drinking Water Treatment Units–Aesthetic Effects,” NSF/ANSI-42, and is published periodically by the Water Quality Association (WQA), as a service to the industry and consumers. The WQA is a not-for-profit international association of manufacturers, distributors, and dealers of water treatment systems for household, commercial, and industrial applications. This on-line directory is continuously updated to identify those water treatment equipment products that have been tested and passed stringent industry standards to become certified by the Water Quality Association.
Certification means that a production model of the listed line of drinking water treatment units was tested at the Water Quality Association laboratory, or any of the other testing laboratories recognized by the Water Quality Association, and was found to have met the standards for reduction of specific aesthetic-related contaminants in drinking water. In addition, the materials and components used in these certified drinking water treatment units have met the rigorous safety and structural integrity and strength requirements set by industry Standard NSF/ANSI-42.‘
Note first that this is an industry sponsored certification and that it is the industry itself that has established the standards. Does that sound the least bit suspicious? It should.
Next note that it doesn’t say anything about total removal of chlorine or chloramine or their byproducts. The term ‘aesthetic effects’ or ‘aesthetic-related contaminants’ are used as substitutes for chlorine or chormamine. Instead it says that the system with the certification met the industry derived standards.
Finally, and here’s the kicker: the standard doesn’t require total removal of the contaminant or even a high percentage of removal.
A new whole house water filter will remove a high percentage of chlorine or chloramine, depending on which type of carbon it uses. That percentage will depend on flow rate. So if you’re running 10 gallons per minute through the system in order to take two showers and run a dishwasher all at the same time you’ll remove less of the contaminant than if the water passes through the system more slowly.
All whole house systems of comparable structure will become saturated with contaminants at about the same time and then have to be replaced or filled with new media. I have numerous systems in place that are five years old and still removing chlorine or chloramine, though they may be removing less than they were when new. At some point the customer will detect chlorine leaking past the system. At that time I suggest that the media be replaced.
What this means to me is that the NSF 42 certification can be meaningless. First you have to find out which contaminant was tested to meet NSF 42. Then you have to determine whether or not there are other equally potential harmful contaminants in your water. If there are not, then your water may be safe to drink in accordance with EPA guidelines. If there are then there is no way that water equipment companies should be encouraging you to drink from every faucet in your home. The NSF 42 standard is useful but it is not in itself an assurance that your water is safe or healthy to drink.
If you’d like to read a long winded article by an employee of NSF which basically says the same thing you may do so here: http://www.wcponline.com/pdf/May_2014_Water%20Matters.pdf
Basically anytime a water equipment provider tells you their system is certified for so many gallons just be aware that it is certified in a lab. They should be telling you that this certification may, or may not, apply to the conditions at your home.
If you want the best whole house water filter for your family then find your local water report and then buy the water purification system or systems that remove the contaminants in your water. NSF certifications may have some value but what you want to find is the type of filter or type of media that removes the contaminants present in your water. My Ultimate Guide (see the link to the right) provides this information. If you buy my Urban Defender whole house water filter, I promise you this: I won’t lie to you about what it does or doesn’t do. You’ll get the facts as best I know them. Whatever you choose to purchase, research well and don’t fall for the hype…