When it comes to choosing a water filtration system, many consumers look first and foremost for a well-known and reassuring logo. Among them, NSF certification is often considered the absolute reference.
However, a preconceived idea persists: an NSF certified filter would automatically be superior to all others.
The reality is more complex.
NSF certification is indeed an excellent indicator of confidence, but it does not, on its own, make it possible to evaluate the overall performance of a filter or the total number of contaminants. studied.
To understand why, it is important to know what NSF certifications actually evaluate.
The main NSF standards used in water filtration
NSF/ANSI 42: aesthetic effects
This standard mainly concerns:
- chlorine;
- taste ;
- odors;
- certain particles.
It mainly aims to improve the comfort of drinking water.
NSF/ANSI 53: effects on health
This standard concerns in particular:
- cysts (Giardia, Cryptosporidium) ;
- lead;
- certain chemical contaminants;
- turbidity.
However, not all NSF 53 certified filters have the same claims.
NSF/ANSI 401: emerging contaminants
This more recent standard covers in particular:
- certain pharmaceutical residues;
- certain pesticides;
- certain herbicides ;
- certain emerging compounds;
- microplastics.
NSF/ANSI/CAN 372: lead-free materials
Contrary to popular belief, this standard does not measure filtration performance.
It simply verifies that the components in contact with water meet the low content requirements. lead.
Understanding the notion of “claim”
An NSF certification does not indicate that a filter has been tested against all possible contaminants.
It only validates certain specific claims called “claims”.
In other words, two NSF certified filters can present very different performances depending on the contaminants actually evaluated.
This is why it is essential to look at the details of the certified claims and not just the presence of an NSF logo.
Concrete example: Ultra Sterasyl from British Berkefeld
Ultra Sterasyl is today the main filter used in British Berkefeld gravity systems manufactured by Doulton.
It benefits from several recognized NSF certifications.
According to the official NSF listings, the certified claims are as follows:
| NSF Standard | Certified Claim |
|---|---|
| NSF 42 | Class I Particulate Reduction |
| NSF 53 | Cyst Reduction |
| NSF 53 | Cyst Reduction turbidity |
| NSF 401 | Microplastic reduction |
| NSF 372 | Low lead compliance |
Source: official NSF International listings.
What this does not mean
The presence of several certifications NSF does not mean that all contaminants have been analyzed or certified.
For example, the NSF claims posted for Ultra Sterasyl do not explicitly cover:
- PFAS;
- fluorides;
- arsenic;
- drug residues;
- pesticides;
- herbicides;
- radionuclides;
- all heavy metals.
This does not mean that the filter is ineffective against these contaminants.
This simply means that these contaminants are not among the certified claims visible in the NSF listings correspondents.
In addition to NSF certifications, Doulton also publishes test results for various contaminants (pesticides, pharmaceutical residues, heavy metals, etc.). According to several sources, these analyzes were carried out by independent, internationally recognized laboratories, based on NSF/ANSI 53 and NSF/ANSI 401 protocols.
Other examples: Coldstream FTO+ and Monderma Imperial GF
The Coldstream FTO+ and Monderma Imperial GF filters perfectly illustrate why it is important not to be limited to the sole presence of a logo NSF.
Unlike some filters on the market, these filters are not NSF certified. However, this does not mean that they have not been subject to rigorous evaluations.
The Coldstream FTO+ filter has notably been evaluated by IAPMO, an organization and laboratory recognized internationally in the field of water filtration. Testing was conducted using NSF/ANSI protocols and covers a wide range of contaminants.
The Mondema Imperial GFfilter, manufactured in the United States, is based on comparable technology combining a ceramic shell and activated carbon media. It has been the subject of evaluations carried out by Envirotek Laboratories, an independent, internationally recognized laboratory, according to NSF/ANSI 42 and NSF/ANSI 53 protocols.
The results published for these different technologies include analyzes concerning:
- bacteria;
- microplastics;
- PFAS;
- fluorides;
- heavy metals;
- pesticides;
- pharmaceutical residues;
- arsenic;
- many others contaminants.
These examples demonstrate that a filter can be evaluated by an independent, internationally recognized laboratory according to NSF/ANSI protocols without having official NSF certification.
Conversely, an NSF certified filter can present a smaller number of certified claims while still fully benefiting from the recognition and credibility associated with this certification.
This distinction is essential to understanding that an NSF certification and tests carried out according to NSF/ANSI protocols are two different but complementary approaches.
NSF certification and laboratory tests: two complementary approaches
NSF certification is an excellent indicator of seriousness.
However, it constitutes only part of the evaluation of a filter.
Manufacturers can also have additional tests carried out by independent laboratories recognized such as:
- NSF International;
- IAPMO;
- Envirotek Laboratories;
- Eurofins;
- Intertek;
- ALS.
These analyzes can cover several dozen, or even several hundred, contaminants.
They often provide a much more complete view of the real performance of a filter.
Why is the number of contaminants analyzed important?
Current consumer concerns go well beyond simple chlorine or particles.
Today, many people want to know the performance of their filtration system with respect to:
- PFAS;
- microplastics;
- heavy metals;
- pesticides;
- herbicides;
- pharmaceutical residues ;
- volatile organic compounds;
- radionuclides.
In this context, detailed laboratory reports become a particularly valuable tool.
A more complete vision of performance
Certain market references, such as Black Berkey®, Coldstream FTO+, Monderma Imperial GF® or even The Imperial AMB® filter from MONDERMA®, manufactured in the United States, have been the subject of extensive testing carried out by internationally recognized independent laboratories such as IAPMO or Envirotek Laboratories. Evaluated according to NSF/ANSI protocols, these tests cover a wide range of contaminants and provide a more complete view of filtration performance beyond just certified claims.
These reports do not replace NSF certifications.
They complete them.
They make it possible in particular to identify:
- the number of contaminants studied;
- the reduction rates obtained;
- the test protocols used;
- the concentrations tested;
- the performances observed over the life of the filter.
For this reason, many specialists today consider that it is relevant to examine simultaneously:
- the NSF certifications obtained;
- the certified claims;
- the laboratories which carried out the tests;
- the number of contaminants analyzed;
- the detailed results of the tests.
How to objectively compare two filters?
To carry out a serious comparison, it is recommended to examine:
✅ The certifications obtained
✅ The associated certified claims
✅ The test protocols used
✅ The laboratories which carried out the analyses
✅ The number of contaminants studied
✅ Published reduction results
✅ Concentrations used in testing
✅ Claimed and tested filter life
Conclusion
NSF certification remains one of the best indicators of confidence available in the water filtration industry.
However, it should not be considered a single indicator or absolute.
An NSF certified filter is not necessarily superior to a filter that has been extensively tested by an independent laboratory.
Similarly, two NSF certified filters may present very different performances depending on the contaminants actually evaluated and certified.
The choice of a filtration system must therefore be based on an overall analysis taking into account both certifications, certified claims and detailed results of laboratory tests.
When it comes to water filtration, the NSF logo is an excellent starting point.
But to truly understand the performance of a filter, it is also essential to examine the certified claims, the test reports, the protocols used, the laboratory which carried out the analyzes as well as the number of contaminants actually studied.
The NSF logo provides strong confidence. Detailed test results provide a more complete view of the reality of filtration performance.
In summary: NSF certification is a valuable tool, but it is the detailed test data that allows you to understand the full story of a product. filter.
