By Dave Bentley

With the onset of the new year, come the infamous resolutions. Whether they are related to exercise, healthy eating, or the ever-popular ’going green‘ concept, it seems that we are all making and/or breaking resolutions. Are you still following yours?

When it comes to resolutions involving better hydration, water typically plays a big role. In most cases for people in the US, our local water utilities do an excellent job providing us with clean and healthy water. In some cases, however, the water that comes to our taps may not be as desirable as a consumer would like. This may be due to concentrations of chlorine high enough to cause taste and odor issues, or elevated hardness due to source water. It could also be something as serious as lead contamination coming from pipes that carried the water from the utility to your residence and, depending on the age of the home, possibly from the plumbing and fixtures.

An overview of standards
NSF International is a third-party certification organization that serves as the secretariat to joint committees responsible for a number of NSF/ANSI standards. These include the NSF/ANSI DWTU standards for POU/POE products. Conscientious consumers are likely aware there are a myriad of water treatment products and technologies for them to choose from. Some are also aware that the majority of these products can be certified to these standards, and actively seek certified products when making purchase decisions.

NSF/ANSI Standards 42 and 53 address POU/POE systems designed to be used for reduction of specific substances that may be present in drinking water (public or private) that is considered to be microbiologically safe and of known quality. The majority of systems certified to these standards are carbonbased, but the scope of these standards also includes other filtration technologies. It is understood that a system may be certified to reduce the concentration of one or more of these substances referenced in the standards, but is not required to treat all substances.

NSF/ANSI Standard 42 covers systems that are intended to reduce substances affecting the aesthetic quality of the water. These substances may be soluble or particulate in nature at levels
that a consumer may find objectionable. NSF/ANSI Standard 53 covers systems that are intended to reduce substances that are considered established or potential health hazards. They may be microbiological, chemical or particulate in nature.

NSF/ANSI Standard 44 addresses manual, auto-initiated and demand-initiated regeneration residential cation exchange water softeners. Those softeners are designed to be used for the removal of hardness and reduction of specific contaminants from drinking water supplies (public or private) considered to be microbiologically safe and of known quality. NSF/ANSI Standard 55, on the other hand, covers UV microbiological water treatment systems for POU/POE applications. Systems certified to this standard fall into one of two categories: class A or class B.

Class A systems are designed to inactivate and/or remove pathogenic (harmful) microorganisms, including bacteria, viruses, Cryptosporidium oocysts and Giardia cysts, from contaminated water. Class A systems are not intended for the treatment of water that has an obvious contamination or intentional source, such as raw sewage, nor are these systems intended to convert wastewater to drinking water. They are intended to be installed for use with visually clear water (not colored, cloudy or turbid).

Class B systems are designed for supplemental bactericidal treatment of disinfected public drinking water. They are designed to reduce normally occurring, non-pathogenic nuisance microorganisms only. These systems are not intended for the disinfection of microbiologically unsafe water, and may not make individual or general cyst claims. Class B systems do not make any microbiological health effects claims.

Moving on to RO systems, NSF/ANSI Standard 58 addresses POU RO drinking water treatment systems that are designed to be used for the reduction of specific substances that may be present in drinking water supplies (public or private) considered to be microbiologically safe and of known quality (except that claims for the reduction of filterable cysts may be permitted). Systems covered by this standard need (at a minimum) to be certified for TDS reduction. During the TDS reduction test, the efficiency, recovery and daily production rate of the system are determined. A manufacturer may make additional contaminant reduction claims on these systems per the test protocols in the standard.

NSF/ANSI Standard 62 addresses requirements for POU/POE drinking water distillation systems. Systems addressed by this standard are designed to reduce specific chemical  contaminants from potable drinking water supplies, and may also be designed to reduce microbiological contaminants, including bacteria, viruses and cysts, from potable drinking water supplies. It is understood that a system may be certified to address one or more of these substances referenced in the standard, but is not required to address all substances.

NSF/ANSI 177 addresses the claim of free available chlorine reduction in shower filtration systems. For a summary on these standards, the product types addressed by each, and the required claims, see Figure 1.

Consumers and certification
In a given month, NSF International’s Consumer Affairs Office receives hundreds of calls and e-mails from consumers who are interested in improving the quality of water that they drink. This provides them with guidance and recommends that consumers get their water tested by a reputable local lab. From review of these test results, the consumer will become educated on any specific contaminants that may be present in their water, and further, which contaminants they would like to focus on reducing.

With this knowledge, and some of the other information available in NSF’s Consumer Fact Kits (, consumers are enabled to determine which technology or technologies will best serve their needs.

Finally, NSF advises consumers to focus their efforts by looking for products that have been tested and certified by ANSI-accredited, third-party certifiers to meet the requirements of the standards. By selecting these products, consumers can be assured that the products are safe to use and will perform as advertised. Armed with the information described above, consumers are much better positioned to meet any New Year’s resolutions relating to safe hydration.

About the author
Dave Bentley is Technical Manager of the NSF Drinking Water Treatment Units Program for certification of POE and POU systems and components. He enjoys leveraging his 15-plus years of experience in this area to help explain the complexities and details of the NSF/ANSI DWTU standards. He can be reached at (800) NSF-MARK or email: [email protected].


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