By Rick Andrew

As I prepare for my retirement at the end of September after more than 24 years with NSF, I can’t help but think back on the evolution of the NSF/ANSI Drinking Water Treatment Unit (DWTU) Standards since this Water Matters column debuted in 2003. On one hand, it is difficult to believe that 20 years have passed. On the other hand, when I consider the development of the standards in that time, I am amazed that it all occurred within two decades.

Introduction of New Standards

Since 2003, several new standards have been created by the NSF Joint Committee on Drinking Water Treatment Units and published. They include the following:

  • NSF/ANSI 177 Shower Filtration Systems – Aesthetic Effects, first published in 2004. This standard allows for certification of shower filters in the reduction of free available chlorine and offers potential for the expansion to additional contaminant-reduction claims.
  • NSF/ANSI 330 Glossary of Drinking Water Treatment Unit Terminology, first published in 2009. It consolidated and increased consistency in definitions across the standards, which previously included significant differences in the definition of terms.
  • NSF/ANSI 401 Drinking Water Treatment Units – Emerging Compounds/Incidental Contaminants, first published in 2014. NSF/ANSI 401 is the first DWTU standard not based on reduction of either aesthetic or health effects contaminants, but on emerging contaminants that end-users would not want in their water. This standard includes 15 contaminants, with reduction requirements and test methods. It could be expanded to include requirements for the reduction of more emerging compounds and incidental contaminants.
  • NSF/ANSI 244 Supplemental Microbiological Water Treatment Systems – Filtration, first published in 2018. NSF/ANSI 244 was under development for several years because of the nature of microbiological contaminants, associated treatment technologies, and the regulatory environment. Completion of this standard was a major achievement for the Joint Committee.

Continued Development of Existing Standards

The existing NSF/ANSI DWTU Standards were developed extensively over the last two decades. They have been reformatted for clarity and modified so the definitions are included in NSF/ANSI 330 instead of in the standards themselves, and many new contaminant-reduction requirements and test methods have been added, including the following:

  • Pentavalent and trivalent arsenic reduction added to NSF/ANSI 53.
  • Perchlorate reduction requirements added to NSF/ANSI 53 and 58.
  • Microcystin reduction added to NSF/ANSI 53.
  • PFOA and PFOS reduction added to NSF/ANSI 53 and 58.
  • A general PFAS reduction claim added to NSF/ANSI 53 and 58.
  • Nitrosamine reduction added to NSF/ANSI 53.
  • 1,2,3-trichloropropane reduction added to NSF/ANSI 53.
  • Requirements for evaluation of LED UV systems added to NSF/ANSI 55.
  • Uranium-reduction requirements added to NSF/ANSI 58.
  • Microplastics reduction added to NSF/ANSI 401.

The added requirements and test methods serve as indicators of the volume of work and overall progress made by the Joint Committee on the development of these standards. Since 2003, there have been 25 new editions of NSF/ANSI 53 published (including addenda) and 18 new editions of NSF/ANSI 58 published (including addenda). We have also seen 20 new editions of NSF/ANSI 42 published (including addenda) since 2003.

Other Significant Advancements

In addition to adding the numerous contaminant-reduction requirements listed above, the Joint Committee has achieved other noteworthy technical improvements to the standards:

  • Enhanced the repeatability and reproducibility of the lead reduction, pH 8.5 test in NSF/ANSI 53 by thoroughly describing the formation and characteristics of the particulate lead component of the challenge. This work on the lead reduction, pH 8.5 test method required several years and the participation of multiple experts and laboratories to accomplish, and it ultimately proved to be a key factor in assuring the reliability of point-of-use (POU) water filters in treating water contaminated with lead.
  • Bridged to NSF/ANSI/CAN 61 by referring to it for evaluation of extraction and safety of materials in contact with drinking water for point-of-entry (POE) products. With this development, the distinction between POU, POE, and municipal end-uses was clearly established with regards to evaluation of material safety.
  • Harmonized the NSF/ANSI DWTU Standards and NSF/ANSI/CAN 61 regarding safe levels for contaminants. This assures consistent evaluation of products in the POU, POE, and municipal categories based on the most up-to-date and scientifically based toxicological risk assessments available.

Expanding International Awareness and Input

Finally, within the last 20 years, international contributors’ participation in the standards process has increased.

In the early 2000s, the standards were almost entirely North American, with input coming mainly from U.S. and Canadian Joint Committee members. However, the international influence of the NSF/ANSI DWTU Standards has grown substantially, and it is reflected in more international participation in the Joint Committee. The committee has included members from Germany, China, Japan, and South Korea, in addition to North America. This increased international participation has benefitted the industry tremendously by enhancing understanding and appreciation of the standards across the globe.

Optimistic About the Future

As I reflect on these amazing developments of the last two decades, I cannot help but be excited to see what the next two decades will bring. With today’s consumer focus on health and wellness, including safe drinking water, we find ourselves in exciting times for the water-treatment industry. New technological and toxicological developments will provide ample opportunities for the industry in the coming years, including opportunities to create standards to help ensure the safety and reliability of products designed and manufactured to treat drinking water. Although I will no longer be at NSF, I will nonetheless remain appreciative of and excited about the efforts of the NSF Joint Committee on Drinking Water Treatment Units.

About the Author
Rick Andrew is NSF’s director of global business development, water systems. Previously, he served as general manager of NSF’s Drinking Water Treatment Units (POU/POE), ERS (Protocols), and Biosafety Cabinetry Programs. Andrew has a bachelor’s degree in chemistry and an MBA from the University of Michigan. He can be reached at 1-800-NSF-MARK or by email at [email protected] until September 29.


Comments are closed.