By Thomas P. Palkon, CWS-VI

History of the Standards
Companies frequently ask the Water Quality Association (WQA), “What’s the difference between WQA’s S-100 Residential Water Softener Testing Standard and the NSF/ANSI 44 Residential Water Softener Testing Standard?” The simple answer is that both standards have been almost completely harmonized. The only difference remaining between them is the Material Safety test procedures.

WQA S-100
WQA published its first version of the S-100 standard in 1959 and shortly thereafter performed the first residential cation exchange water softener certification. Thousands of certifications since have established WQA’s expertise in water softener testing and certification. The 1959 version has gone through many revisions over the past 39 years, but the purpose has remained consistent: water softeners must be developed using safe materials, built structurally sound and perform in accordance to the specifications published in there literature.

NSF International (NSF) published the first version of the ANSI/NSF 44 standard, developed using the American National Standards Institute (ANSI) standards writing process and criteria, in 1987. WQA allowed NSF to use the S-100 standard test criteria in the development process of the ANSI/NSF 44 standard, because of the tremendous amount of WQA member research and effort that went into developing the S-100. This was the beginning of the excellent working relationship between the two organizations. Even though WQA and NSF are competitors when it comes to testing and certification, the friendly working relationship that began over 20 years ago still exists today.

Harmonization effort
Even though the two standards were similar in scope and purpose they did contain some differences in testing requirements and procedures. WQA’s Water Sciences Committee thought it would be best for all if the two could be harmonized so that companies seeking testing and certification would only need to meet the requirements of a single industry standard for water softeners. WQA’s Water Science Committee and Ion Exchange Task Force and NSF’s Joint Committee for Drinking Water Treatment Units (DWTU) worked diligently in an effort to harmonize the two standards. The process went on for several years, resulting in complete harmonization of all test procedures and literature requirements except for one section, Material Safety.

WQA’s Water Science Committee wanted to keep two Material Safety testing options in the S-100 standard. Material safety testing ensures that the products will not extract contaminants into the drinking water above safe levels. The first option is to follow the extraction test procedure outlined in the current version of the NSF/ANSI 44 standard; the second option is to require manufacturers to certify that all the materials in contact with the drinking water comply with US Food and Drug Administration (US FDA) Title 21 Code of Federal Regulations for Food Additives. This second option of the S-100 standard that ensures Material Safety ended the harmonization of the two standards and is still the only difference between them as they exist today.

Requirement comparison
The following chart outlines the basic requirements of the two standards. These, along with other standards for water filters, water softeners, ROs, UVs and distillers contain four main sections: material safety, structural integrity, performance testing and literature requirements. The chart here provides a picture of how closely harmonized the S-100 and NSF/ANSI 44 standards exist today. Because the standards are so similar, a company unsure of which standard they want their products certified against can perform all tests to either one and make their certification decision at a later date.

Regulatory acceptance
What does having two standards mean for companies seeking certification? Most companies seek certification for one of two reasons: regulatory compliance or marketing advantages. The WQA S-100 and NSF/ANSI 44 standards can be used to meet state regulations and plumbing codes but because state agencies and do not like when two standards exist for a single product they are not always accepted or adopted together. If you are seeking certification to meet a regulation or plumbing code, know the geographical market that the units will be sold in and check with local regulators, plumbing codes or with certification agency to ensure testing is conducted to the appropriate accepted water softener standard for that region. If a company is getting their water softener(s) certified to inform consumers that the product has been tested and certified by a third party organization, the company should choose the standard they feel provides the best marketing advantages for the testing and certification costs.

Testing and certification
WQA like other certification agencies that are accredited by the American National Standards Institute (ANSI), offers testing and certification to a variety of industry standards for many different types of products, components or additives that contact drinking water. WQA will continue to provide testing and certification of water softeners to the WQA S-100 and NSF/ANSI 44 standards as long as companies continue to request the work. Most companies requesting WQA certification today prefer that testing is performed to the NSF/ANSI 44 standard. Many companies still find that the S-100 Standard is the preferred water softener testing standard for their business.

About the author
Tom Palkon is the Director of Product Certification for the Water Quality Association. Tom has managed and operated WQA’s Laboratory, Facility Assessment and Certification departments the past 9 years. Tom holds a Bachelor of Science degree from the University of Illinois (Champaign-Urban) and a Master of Business Administration with Distinction from Keller Graduate School of management. Tom can be contacted by phone 630-505-0160 ext 523 or email [email protected]


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