NSF Certifications and Imperial Filters: Understanding Water Filtration Standards
When choosing a water filter, you may come across mentions such as NSF/ANSI 42, NSF/ANSI 53, NSF/ANSI/CAN 372, NSF/ANSI 401 or NSF P231. These references constitute neither a rating nor a ranking of the filters. They correspond to standards or test protocols relating to specific criteria: quality of materials, resistance of the system or reduction of certain contaminants.
⚠️ Essential point
A filter certified to an NSF standard does not automatically reduce all contaminants covered by that standard. It is always necessary to check the performance claims which appear on the certificate or in the official product listing.
A filter certified to an NSF standard does not automatically reduce all contaminants covered by that standard. It is always necessary to check the performance claims which appear on the certificate or in the official product listing.
NSF certification or testing according to an NSF protocol: what is the difference?
🏅 NSF certified product
Comprehensive assessment: declared performance, material safety, structural integrity, documentation and regular inspections of the manufacturing site.
Certification remains limited to the performances expressly mentioned.
Comprehensive assessment: declared performance, material safety, structural integrity, documentation and regular inspections of the manufacturing site.
Certification remains limited to the performances expressly mentioned.
🔬 Product tested according to NSF protocols
Analysis by an independent laboratory applying methods inspired by NSF/ANSI standards. Can provide very detailed information.
Do not confuse with “NSF certified”. View the report, concentrations and reduction percentages.
Analysis by an independent laboratory applying methods inspired by NSF/ANSI standards. Can provide very detailed information.
Do not confuse with “NSF certified”. View the report, concentrations and reduction percentages.
NSF/ANSI 42: taste, odor and aesthetic quality
- Objective: improve the aesthetic characteristics of drinking water.
- Possible allegations: reduction of chlorine, taste and odor, particles, chloramine or certain elements affecting the appearance of water.
- To remember: mainly concerns consumption comfort and not contaminants presenting a health risk.
An NSF/ANSI 42 certified filter can be effective in improving the taste of water without being certified for the reduction of lead, PFAS, or other substances with a potential health effect.
NSF/ANSI 53: Contaminants Affecting Health
- Objective: evaluate the reduction of contaminants that could have a health effect.
- Possible allegations: lead, mercury, chromium, asbestos, cysts, volatile organic compounds, nitrates, nitrites and other contaminants covered by the standard.
- Essential point: the standard offers more than 50 possible claims, but a product does not need to be certified for each of them.
⚠️ The mention NSF/ANSI 53 is not sufficient on its own to know the complete performance of a filter. It is necessary to check each contaminant precisely indicated on its certificate.
NSF/ANSI/CAN 372: limitation of lead in materials
- Objective: control the lead content of materials used in equipment in contact with drinking water.
- Main requirement: weighted average lead content not exceeding 0.25% for surfaces in contact with water.
- To remember: concerns the composition of the product, not its ability to remove lead already present in water.
NSF/ANSI 401: emerging contaminants
- Objective: evaluate the reduction of compounds detected at trace levels in certain drinking water resources.
- Scope: up to 15 emerging contaminants or accidental compounds.
- Categories concerned: residues from drugs, hormones, pesticides, herbicides, industrial chemicals, flame retardants and detergents.
Substances covered may include bisphenol A, ibuprofen, naproxen, estrone, DEET, atenolol or certain industrial compounds.
NSF P231: microbiological purification
- Objective: evaluate purifiers intended to treat water whose microbiological quality may be uncertain.
- Bacteria: minimum reduction of 99.9999% (6 log).
- Viruses: minimum reduction of 99.99% (4 log).
- Protozoan cysts: minimum reduction of 99.9% (3 log).
⚠️ Compliance with this protocol must be verified for precise model concerned. A brand cannot automatically claim P231 compliance for all of its products.
Why the number of certifications is not enough
It is common to read that the more NSF standards a filter has, the more efficient it would automatically be. This conclusion is too simplistic.
To properly compare two filters, look at:
- contaminants precisely tested or certified;
- the reduction percentages obtained;
- the concentrations used during the tests;
- the total capacity tested in liters;
- throughput during analyses;
- the initial quality of the water used;
- the identity and accreditation of the laboratory;
- the presence of an official certification or an independent test report.
The new generation of Imperial filters
🇺🇸 From September 2026, Monderma introduces a new generation of gravity filters Imperial Filters®, made in the USA. This range combines a microporous ceramic mechanical barrier with different filtration media capable of acting by adsorption and, depending on the model, by ion exchange.
Imperial AMB: microporous ceramic and activated carbon block
The filter Imperial AMB combines a microporous ceramic envelope with a block of activated carbon:
- mechanical filtration of particles, sediments and physical contaminants retained by ceramic;
- adsorption of targeted substances by activated carbon media.
The Imperial AMB filter benefits from a NSF certification for the claims specifically stated on its certificate. Indicative autonomy: up to 12 months per pair of filters.
Imperial GF: ceramic, granular activated carbon and zeolite
- Microporous ceramic: mechanical barrier against fine particles, sediments and micro-organisms.
- Granular activated carbon: adsorption of many organic compounds and improvement of taste and odor.
- Natural zeolite: complementary media by adsorption and ion exchange.
🔬 The filter Imperial GF was the subject ofindependent analyzes according to NSF/ANSI protocols 42 and 53, covering more than 200 contaminants and parameters analyzed. This extensive campaign, however, should not be presented as official NSF certification.
Imperial AMB or Imperial GF: how to choose?
| Criterion | Imperial AMB | Imperial GF |
|---|---|---|
| Manufacturing | United States | United States |
| Exterior barrier | Microporous ceramic | Microporous ceramic |
| Indoor media | Activated carbon block | Granular activated carbon + zeolite |
| Evaluation | NSF certification (claims indicated) | Independent analyzes NSF/ANSI 42 and 53 |
| Scope of analyzes | To check on the certificate | +200 contaminants analyzed |
| Indicative autonomy | Up to 12 months per pair | Up to 12 months per pair |
Which filter to choose depending on the origin of the water?
🚰 Public network water
Normally controlled and disinfected. Direct the choice towards the reduction of chlorine, tastes and odors, particles, certain metals or identified chemical contaminants.
Filters Imperial AMB and Imperial GF provide several complementary levels of processing.
Normally controlled and disinfected. Direct the choice towards the reduction of chlorine, tastes and odors, particles, certain metals or identified chemical contaminants.
Filters Imperial AMB and Imperial GF provide several complementary levels of processing.
⛏️ Water from well, borehole or spring
Requires a regular microbiological and physicochemical analysis. No filter should be chosen solely on the basis of its technology.
Verify that the system has documented performance for bacteria, viruses, parasites and chemical contaminants actually present.
Requires a regular microbiological and physicochemical analysis. No filter should be chosen solely on the basis of its technology.
Verify that the system has documented performance for bacteria, viruses, parasites and chemical contaminants actually present.
Summary of main standards
- NSF/ANSI 42: aesthetic effects — chlorine, taste, odor, certain particles.
- NSF/ANSI 53: contaminants having a health effect.
- NSF/ANSI/CAN 372: limitation of the lead content of materials.
- NSF/ANSI 401: reduction of emerging contaminants (up to 15 substances).
- NSF P231: protocol for microbiological purifiers.
Things to Remember Before Buying a Water Filter
✅ In summary
An NSF certification never means that a filter reduces all contaminants associated with a standard. The real information is in the exact list of certified claims.
With the filters Imperial AMB and Imperial GF, Monderma offers two complementary approaches: targeted certification and an extensive independent analysis campaign. This transparency makes it possible to choose a filter based on documented results rather than simple commercial promises.
An NSF certification never means that a filter reduces all contaminants associated with a standard. The real information is in the exact list of certified claims.
With the filters Imperial AMB and Imperial GF, Monderma offers two complementary approaches: targeted certification and an extensive independent analysis campaign. This transparency makes it possible to choose a filter based on documented results rather than simple commercial promises.
