NSF Standards For Water Filters That Remove PFAS

There are steps you can take to protect yourself (and your family) from PFAS, or ‘forever chemicals’. The National Sanitation Foundation (NSF) has set standards in place for water filters to certify they are truly capable of removing PFAS from your drinking water.

At the moment, NSF/ANSI 53 and NSF/ANSI 58 are the two standard certification protocols that confirm a filtration system is able to reduce PFAS safely and effectively. Previously, NSF P473 (launched in 2016) was the standard. 

In this article, we go into detail on what an NSF/ANSI 53 and 58 certifications include, and explain how you can use this information to help remove PFAS from your water.

NSF Standards For PFAS

NSF, or National Sanitation Foundation, is an independent organization that creates guidelines and standards about the quality and safety of differentproducts and services concerning water, food, and beverages. 

Based on its guidelines, NSF performs independent tests of products and services, and if they are found to comply with the guidelines, gives them an official NSF certification. Once a product is certified, to maintain its certified status, it must be inspected regularly, and the manufacturing facilities are also checked each year.

The NSF site also lists all products that are certified – making it easy to check how your brand fares. 

Achieving NSF certification is a rigorous process and products need to meet several strict criteria for safety and quality. As such, you can use NSF certification as an indicator for safety and reliability of a product. 

Currently, two different NSF standards cover PFAS: NSF/ANSI 53 and NSF/ANSI 58.


The NSF-53 standard tests filters that aim to ‘reduce contaminants with a health effect’. This includes PFAS because it negatively affects our health. 

The safety levels for each contaminant, including PFAS, is decided based on guidelines by the Environmental Protection Agency (EPA), or in some cases Health Canada. 

This standard deals with point-of-use filters that are carbon based, like water filter pitchers and under-sink filters.

For more information on water filter pitchers that can remove PFAS read this.


The NSF-58 deals specifically with reverse osmosis systems and its components.

Reverse osmosis (RO) is a powerful filtration system that can deal with several different types of contaminants including PFAS from water. This standard therefore has guidelines and protocols to test how well RO systems remove PFAS (along with other contaminants).

We have more information on reverse osmosis systems able to remove PFAS available here.

A Note on NSF P473

In 2016, NSF developed a protocol called NSF P473 that described standards to be used for detecting PFAS in water. This was the first of its kind at the time when it was launched.

However, as more information began to pour in about the ill effects of PFAS, more rigorous standards were needed both for testing PFAS and for confirming technologies could reduce PFAS from water. As such, NSF and American National Standards Institute (ANSI) jointly released standards 53 (for carbon-based products) and standard 58 (for reverse osmosis based products).

These two standards included the testing guidelines that were already described in NSF P473, making it redundant. As such, NSF/ANSI 53 and 58 are the only current NSF standards in place. 

With ongoing research, these guidelines are being frequently updated, and now include information for multiple different compounds that fall under the common name ‘PFAS’, including:

  • GenX: Perfluoro-2-methyl-3-oxahexanoic acid
  • PFBS: Perfluorobutane sulfonate
  • PFBA: Perfluorobutanoic acid
  • PFHpA: Perfluoroheptanoic acid
  • PFNA: Perfluorononanoic acid
  • PFOS: Perfluorooctane sulfonate
  • PFOA: Perfluorooctanoic acid
  • NFBS: Nonafluorobutanesulfonamide

How NSF certification helps you

With PFAS becoming the new ‘buzzword’ in the health arena, many companies have begun to claim that their filters can remove PFAS from water. However, not every product has met the strict requirements to do so, and if you end up purchasing these products, you may be putting your health at risk.

This is a big issue because PFAS are currently NOT regulated in US drinking water supplies, and for now you must rely on effective filtration systems to guarantee the PFAS levels in your drinking water are safe. 

On March 14, 2023, EPA announced a proposed National Primary Drinking Water Regulation for six PFAS chemicals.

As per the NSF website, any time a product receives NSF certification for PFAS reduction, it means that:

  • The contaminant reduction claims for PFAS shown on the label are true.
  • The system doesn’t add anything harmful to the water.
  • The system doesn’t leak.
  • The product labeling, advertising and literature are not misleading.

This means that NSF certification is like a guarantee to us that the product we are buying is genuinely capable of removing PFAS from our drinking water. 

The NSF website also lists the products that it has independently assessed and verified, making it easier for us to find quality filters that can safely reduce PFAS levels in the water you drink. 

PFAS Exposure

PFAS is the much easier to say and remember abbreviation for per- and poly-fluoroalkyl substances. These chemicals have been used since the 1940s in many commonplace materials like nonstick pans/cookware, popcorn bags, paint, cosmetics, cardboard food packaging, furniture fabric, plumbing tape, and waterproof clothing. 

Because it’s used in such a big range of materials, large quantities of these substances have been released into the environment, and are now found commonly in soil and water, possibly including the tap water supply to your home as well.

PFAS are also known as ‘forever chemicals’ because they are exceptionally resistant to natural degradation from heat, water, grease or oil. This makes them problematic, because they are known to be toxic – even at very low levels.

Linked Effects

We are only beginning to learn about the dangerous effects that PFAS has on our body, especially since it has a tendency to accumulate or build-up in our body over time and slowly show its toxic effects. 

Some of the effects that we have already seen include the following:

  1. Dyslipidemia (high cholesterol levels)
  2. Transaminitis (Elevation of liver enzymes)
  3. Imbalance in testosterone and estrogen levels
  4. Thyroid dysfunction
  5. Low birth weight
  6. Immune Dysfunction

Safe Levels

The total level of PFAS in water should be less than 70 parts per trillion (PPT), according to EPA standards set in 2016.

However there are far lower standards set for specific subtypes of PFAS as follows:

  1. PFOS : 0.02 PPT
  2. PFOA : 0.0004 PPT

It’s likely that the overall acceptable level of PFAS in our water will drop over time as more research is done. PFOS and PFOA have undergone more research than other types, and have a far lower limit in water. Watch this space – as we discover more about these forever chemicals.

Theresa Orr

Theresa Orr is an Earth Scientist who specializes in determining past climates from rocks using geochemistry. Her passion for clean water drives her to breakdown the science to provide easy to understand information that everyone can read.

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