NSF 372 vs 401: What are the Differences?

We need water to sustain life, and not just any water but clean water. Any contaminant in your water can be detrimental and harmful to consume.

Getting a water system that ensures that you get safe drinking water isn’t an easy task. The amount of constantly changing information is sometimes confusing even to those with years of experience.

That’s why the National Sanitation Foundation (NSF) international has set standards that help to assure safe and reliable treatment and delivery of drinking water.

In this post, we compare two NSF standards, NSF 372 vs. 401, to help you understand both better. Continue reading to learn more.

Comparing NSF 372 vs 401

FeatureNSF/ANSI 372NSF/ANSI 401
ScopePipes, plumbing fixtures, and fittings.Point-of-use and point-of-entry systems.
ClaimOutlines general requirements that relate to lead content in water.Offers up to 15 contaminants reduction claims for prescription drugs, OTC medications, chemical compounds, herbicides, and pesticides.
TestingMaterial safety, structural integrity, and lead-free claims.Material safety, structural integrity, and emerging/incidental contaminants.

What is NSF 372?

The NSF 372 establishes a limit on the amount of lead that can be within the water contact materials in a given drinking water contact product.

It applies to all drinking water components that convey or dispense water for consumption through cooking or drinking.

In meeting the need, this standard certifies utilities, regulatory agencies, organizations, and manufacturers to provide assurance that their products meet public health requirements.

NSF 372 outlines general requirements that relate to the lead content of fluxes and solders and the formula for determining average lead content.

It also outlines the percentage of lead in liners and coatings, lead content analytic procedures, and lead removal technologies.

What is NSF 401?

NSF 401 is a recently established standard for water filters that can filter emerging compounds and incidental contaminants.

It was established when public water users got concerned about trace pharmaceuticals getting into tap water.

Some of the contaminants removed by a filter with an NSF 401 certification include atenolol, carbamazepine, estrone, meprobamate, phenytoin, and trimethoprim.

Some of the water filters that might come with the NSF 401 certification include activated carbon filters and under-sink carbon block.

What are NSF/ANSI Standards 42, 53,401?

NSF/ANSI Standard 42

The NSF/ANSI 42 is one of the most available NSF standards today. The most commonly tested chemical reduction for products seeking certification of this standard include; chlorine, manganese, hydrogen sulfide, chloramines, zinc, and PH neutralization.

The filter doesn’t have to remove or reduce all the contaminants listed above to be NSF certified.

If you come across a filter advertised to be NSF/ANSI standard 42 certified for chloramine reduction, note that the filter provides high-level performance when it comes to reducing chloramines.

Before being certified with this standard, a filter is installed and operated at a 60-psi dynamic inlet pressure. It is then run at the manufacturer’s desired service flow rate until its service capacity is achieved.

Testing for POE chemical reduction, iron, and manganese requires you to test only one system. On the other hand, testing for POU chemical reduction claims is conducted in duplicate.

All these chemical reduction tests are run using a 16-hour test period with an 8-hour rest period. This is always the case unless the filter’s rated capacity is achieved before the 16 hours of testing lapses.

For whole-house POE systems, a system is tested continuously for 16 hours, followed by an 8-hour rest period every day until the rated capacity is achieved.

All chemical reduction testing for NSF 42 is carried out to 100% of the manufacturer’s desired reduction capacity, with the exception of iron and manganese conducted to 120% of the unit’s reduction capacity.

NSF/ANSI Standard 53

The NSF/ANSI standard 53 is a common certification awarded to filters capable of eliminating specific contaminants known to cause health effects.

Filters with the NSF 53 certification don’t provide a set contaminant reduction. Different filters certified with this standard remove different types of contaminants.

Some of the impurities that NSF/ANSI standard 53 certified filters remove include copper, lead, VOCs, mercury, barium, cadmium, chromium 3, selenium, toxaphene, cyst, bacteria, asbestos, and arsenic, among others.

All companies must provide a performance data sheet for their water filters. The sheet should show precisely which contaminants the filter removes.

The testing for standard 53 differs from standard 42 in that the testing is done at the maximum rate resulting from a 60-psi dynamic pressure. It is then run to either 120% or 200% of the manufacturer’s desired reduction capacity.

Most NSFI/ANSI 53 certified products are under-sink systems. In addition, several faucet-mount water filters are also certified under the standard.

NSF/ANSI Standard 401

As aforementioned, NSF/ANSI 401 is a recently established standard intended for water filters capable of removing emerging compounds and incidental contaminants.

A filter with this certification removes or reduces up to 15 types of emerging impurities like prescription drugs, detergents, flame retardants, certain pesticides, and herbicides.

Most under-sink carbon blocks or activated carbon filters come with the NSF/ANSI standard 401 certifications. Countertop filters may also be certified to the standard.

Which Water Filters Remove the Most Contaminants?

Water filtration has become a necessity now that a lot of contaminants make their way into the water supply. The good news, however, is that technology has made it easier to eliminate these impurities using water filters.

Reverse osmosis water filters are the most effective. They have a high-quality cartridge system that removes particles as tiny as 0.0001 microns.

The filters remove almost all organic molecules, minerals, and viruses to produce pure, filtered water.

Which Filter is best for Drinking Water?

Reverse osmosis filters are the best. They remove a large percentage of contaminants from the water, including heavy metals, VOCs, and dangerous waterborne bacteria.

These filters work by pushing through the RO membrane using pressure.

Final Word

NSF/ANSI-certified products assure you that the products are safe, perform as expected, and don’t make any misleading or false claims.

However, it’s important to note although some manufacturers claim that the product is NSF certified, it might not be true. If you doubt the certifications, ask for official NSF documents from NSF testing for verification.

You can also visit the NSF’s catalog and search for the product. If the filter isn’t there, that’s a big red flag.

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