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What are NSF Certifications for Water Filters?

NSF Certifications Explained

 

Have you ever wondered what the ‘NSF’ acronym means on the packaging or websites of some water treatment products? Or, better yet, what it means when those three letters aren’t there? We’ll go over the basics in this blog post so you not only understand that designation, but are able to make more informed choices when you’re shopping around for water treatment products.

What is the NSF?

The National Sanitation Foundation (NSF) is an independent product testing, inspection, and certification organization.

Note: This NSF is not to be confused with the National Science Foundation. 

One of the many functions of the NSF is to conduct testing and certification of water treatment devices to ensure that the devices are composed of nontoxic materials and/or that they reliably and adequately remove certain contaminants. 

Federal agencies that regulate drinking water (i.e. the EPA and FDA) do not regulate treatment devices, so certifications aim to provide unbiased information to help consumers decide which products will be effective for their water treatment needs. Some of the most popular NSF certifications address materials safety, structural integrity and specific contaminant reduction claims. [1]

Are There Other Certification Organizations?

In addition to the NSF, there are a couple of other relevant agencies that also certify water treatment products, often in conjunction with the NSF.

The American National Standards Institute (ANSI) is a US-based non-profit organization that manages the development of voluntary consensus standards for products, services, techniques, systems, and personnel. ANSI helps establish national standards and identify gaps in conformity assessment activities. Another major role of ANSI is to accredit the organizations that uphold industry standards, including certification labs, inspection bodies, personnel credentialing bodies, and other conformity assessment structures used to hold people and industries accountable. In conjunction with the National Sanitation Foundation, ANSI has developed a multitude of standards for at-home water treatment products. [2]

The Water Quality Association (WQA) is an organization that conducts research, education, and product testing and certification for the water treatment industry. The WQA tests drinking water treatment system components, water additives, pool and spa equipment, and food equipment that involves potable water. The agency provides the WQA Gold Seal Certification to products that have undergone testing in WQA's lab or other certified labs, and meet quality standards established by the NSF and ANSI. WQA tests and certifies products for safe materials, removal claims by manufacturers, and sustainability. WQA certifications are useful for consumers when considering which products will be effective for their needs. [3]

What Does ‘Certification’ Mean?

In the context of home water treatment products, ‘certification’ means that the product has performed to the standards that are specified in the specific certifications. Essentially, the product has passed the test that the agency designed. These tests are typically called ‘challenge tests’ and involve adding a specific amount of a contaminant to water and determining how much of that contaminant the product removes, then comparing that removal with the amount of removal specified in the standard. The certifications that we are focused on here are developed jointly by the NSF and ANSI and are referred to as NSF/ANSI, followed by a number. The WQA uses the NSF/ANSI standards for its own certification so we’ll be discussing NSF/ANSI certifications only.

Some Specific NSF Certifications Explained

When it comes to NSF/ANSI certifications, there are a couple of points that apply to all certifications:

  1. Each of these certifications is awarded on a contaminant by contaminant basis, meaning that a given product with a specific certification is not necessarily certified for the reduction of all contaminants that the certification standard covers. For example, the NSF/ANSI 42 standard covers many contaminants, including chlorine, chloramines and iron. A product may be NSF/ANSI 42 certified for chlorine only, which gives no information about the other contaminants covered by NSF/ANSI 42 certification.

  2. The standards typically include requirements for the materials safety, design, and construction of the water treatment products. The distinct aspect of the standards is the contaminants that they are certified to remove.

Here is a quick run down of some of the most relevant certifications when it comes to home water treatment devices.

NSF/ANSI 42 Standard

The NSF/ANSI 42 standard is used to certify products for removing or reducing concentrations of contaminants that may cause negative aesthetic effects (i.e. color, taste and odor impacts). The standard establishes minimum requirements for removing or reducing the concentrations of compounds that cause an unpleasant taste, odor or color in drinking water, including aesthetic chlorine, chloramines, sizable particulates and microbes, manganese, iron, and zinc. NSF/ANSI 42 certification is used for both point of use (i.e. under the sink and pitcher filters) and point of entry systems. [4][5]

NSF/ANSI 53 Standard 

The NSF/ANSI 53 standard is used to certify water treatment products for removing or reducing concentrations of contaminants that have the potential to cause health problems. The standard establishes minimum removal requirements for specific health-related contaminants. Some of the contaminants included in this certification are lead, asbestos, volatile organic compounds, Cryptosporidium, perfluoroalkyl substances (PFAS), and chromium. NSF/ANSI 53 certification is used for both point of use (i.e. under the sink and pitcher filters) and point of entry systems. [5][6]

NSF/ANSI 401 Standard 

The NSF/ANSI 401 standard is used to certify water treatment products for removing or reducing concentrations of contaminants that have effects that are not fully researched (i.e., ‘contaminants of emerging concern’). The NSF established this certification due to increasing consumer concerns about potential effects from exposure to various emerging contaminants via drinking water. The standard establishes minimum requirements for the removal or reduction of certain emerging contaminants of concern, including a number of pharmaceuticals and pesticides. NSF/ANSI 401 certification is used for both point of use (i.e. under the sink and pitcher filters) and point of entry systems. [5][7]

NSF/ANSI 58 Standard 

The NSF/ANSI 58 standard is used to certify point of use (e.g. under the sink) water treatment systems employing reverse osmosis, a high-pressure filter technology designed to remove a wide array of contaminants of concern. NSF/ANSI 58 establishes minimum requirements for total dissolved solids (TDS) reduction and contaminant removal or reduction. Some of the contaminants included in this certification are nitrate, lead, arsenic, volatile organic compounds, 

NSF/ANSI 44 Standard 

The NSF/ANSI 44 standard is used to certify cation exchange water softeners for residential use. Water softening products covered by NSF/ANSI 44 reduce hardness by replacing calcium and magnesium with sodium or potassium. The standard establishes minimum requirements for the softening capacity and regenerated salt concentration of the products. It also dictates minimum removals for hardness minerals and certain other cations, including barium and radium. The NSF/ANSI 44 certification is used for both point of use (i.e. under the sink) and point of entry water softening systems. [9]

NSF/ANSI 55 Standard 

The NSF/ANSI 55 standard is used to certify ultraviolet disinfection treatment systems designed to deactivate bacteria, protozoa, and viruses. The standard establishes requirements for the disinfection performance, material performance, and labeling information for certified products. There are two UV water treatment system classifications covered under this standard, Class A and Class B. Class A products have been tested and certified to reduce prevalent protozoa resistant to typical chlorine disinfection, including cryptosporidium and giardia, as well as bacteria and viruses to safe levels. Class B products have been tested and certified to further reduce microbe concentrations in water that is already deemed safe by health agencies. Class B certified products should not be used in the case of known harmful microbial contamination. The NSF/ANSI 55 certification is used for both point of use (i.e. under the sink) and point of entry UV systems. Even Class A certified products are not recommended for cloudy, turbid water or water with a clear source of contamination. For example, these products should not be used to convert sewage wastewater to drinking water. [10][11]

NSF/ANSI 177 Standard

The NSF/ANSI 177 standard is used to certify point of use shower filters. Some studies suggest that elevated levels of chlorine in tap water left over from disinfection processes can dry out the skin and damage hair. NSF/ANSI 177 certified shower filters are certified for labeling information and the reduction of free available chlorine. [12][13]

NSF/ANSI 62 Standard 

The NSF/ANSI 62 standard is used to certify distillation water treatment systems for residential use. Distillation systems heat water to its boiling point and collect the evaporated water, leaving behind most harmful contaminants. NSF/ANSI 62 establishes requirements for TDS reduction and the reduction of additional contaminants, including arsenic, chromium, mercury, nitrate, nitrite, bacteria, and protozoan cysts. The NSF/ANSI 62 certification is used for both point of use (i.e. under the sink) and point of entry distillation systems. [14][15]

Certification

Description

Selected Reduction Claims

Location(s) of Products

NSF/ANSI 42

Reduction of contaminants that may cause negative aesthetic effects (i.e. taste, odor or color issues)

Chlorine

Taste and Odor

Chloramine

Particulates

Large pathogens

Iron

Manganese

Zinc

Point of use

Point of entry

NSF/ANSI 53

Reduction of contaminants that may cause negative health impacts

Lead

Asbestos

Volatile organic compounds (VOCs

Cryptosporidium

Perfluoroalkyl substances (PFAS)

Chromium

Point of use

Point of entry

NSF/ANSI 401

Reduction of contaminants that have effects that are not fully researched (i.e., ‘contaminants of emerging concern’)

Certain pharmaceuticals

Certain pesticides

Point of use

Point of entry

NSF/ANSI 58

Reduction of TDS (required) and certain other contaminants by  reverse osmosis systems

Nitrate

Lead

Arsenic

VOCs

Radium

Fluoride

Point of use

NSF/ANSI 44

Establishes requirements for the softening capacity and regenerated salt concentration, as well as the reduction of certain contaminants, for cation exchange water softeners

Hardness minerals

Certain other cations, including barium and radium

Point of use

Point of entry

NSF/ANSI 55

Establishes requirements for the disinfection performance, material performance, and labeling information for ultraviolet disinfection (UV) treatment systems*

Class A:

Prevalent protozoa resistant to typical chlorine disinfection, including Cryptosporidium and Giardia

Bacteria

Viruses


Class B:

Further reduction of microbes in water deemed safe by public health agencies

Point of use

Point of entry

NSF/ANSI 177

Establishes requirements for labeling and contaminant reduction for shower filters

Free available chlorine

(Some studies suggest that chlorine can dry out the skin and damage hair)

Point of use

NSF/ANSI 62

Reduction of TDS (required) and certain other contaminants by distillation units

Arsenic

Chromium

Mercury

Nitrate

Nitrite

Bacteria

Protozoan Cysts

Point of use

Point of entry

*UV products are not recommended for use with cloudy, turbid water or water with a clear source of contamination

Are NSF Certified Water Treatment Products Better?

The short answer: not necessarily. Many uncertified products reduce contaminants to the same degree as their certified counterparts, it’s just hard to know if the manufacturer claims of contaminant reduction are accurate without third party testing. The reason that some companies don’t get their products certified is that the testing and certification can be expensive so some companies choose not to certify even if the products would pass. In the end, NSF certifications give credence to manufacturer claims regarding contaminant reduction. Without certifications, you’ll need to look more deeply into the product and perhaps even test the treated water yourself.

If you have a treatment product and you’re concerned about its capabilities, or you just want to be sure that it’s reducing the contaminants you care about, consider purchasing one of our advanced tests (either city or well depending on your water source) to check the final water quality. Or buy two and do a before and after!

Core Kit
Advanced City Water Test
109 Analytes Tested
$350.00
Core Kit
Advanced Well Water Test
112 Analytes Tested
$373.00
As always, if you have any water or testing-related questions, feel free to reach out to the SimpleLab team of water quality engineers, treatment experts, and chemists. They are always available to help you out. Send them a message any time at hello@gosimpelab.com.

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