Emerging Standards

Aug. 30, 2019

NSF. Intl. updated two standards for drinking water treatment and reverse osmosis to include standards for PFOA and PFOS

About the author:

Jessica Evans is director of standards development for NSF Intl. Evans can be reached at [email protected]


The NSF Intl. joint committee updated two standards for drinking water treatment and reverse osmosis to include test methods and requirements for the reduction of perfluorooctanoic acid (PFOA) and perfluorooctane sulfonate (PFOS). WQP Associate Editor Sara Myers spoke with Jessica Evans, director of standards at NSF Intl., about increased public awareness of per- and polyfluoroalkyl substances (PFAS) contamination in drinking water and the need for the updated standards. 

Sara Myers: What was the reasoning behind the update?

Jessica Evans: Updating the standards to incorporate test methods for PFOA and PFOS reduction claims in filters was always our intention. The NSF/ANSI consensus-based process to develop standards is rigorous and time-consuming, as it involves all stakeholders and requires a public comment period. The timeline to develop a protocol is usually much shorter, so establishing Protocol 473 allowed NSF to take an initial step to address—in a more timely manner—this immediate public health concern of PFAS contaminants being found in groundwater. In doing so, NSF Intl. was the first organization to establish scientific methods to test and certify residential drinking water filters for the reduction of PFOA and PFOS, the two most common PFAS chemicals. 

Many consumers are unaware that there are certified filters available to reduce PFAS and other contaminants. As of today, 10 manufacturers are producing a total of 76 different products that have been NSF-certified to reduce PFOA and PFOS to below the U.S. EPA’s health advisory level of 70 ppt.

Myers: When will additional updates be released?

Evans: Additional PFAS compounds will be added as health criteria is gathered and published by regulatory agencies. Currently, there is a lack of published toxicological criteria to support the inclusion of these additional compounds into the NSF standards. With respect to a timeline, I expect NSF to have significant updates in all these areas within the next 12 months.

Myers: PFAS contamination in drinking water recently has been a hot topic for the water industry. Why do you think this is?

Evans: PFAS is a public health concern. Awareness is growing as more testing of groundwater quality is conducted by states and more contaminated areas are discovered. A number of states have already established or are considering establishing their acceptable levels of PFOA and PFOS to be considerably lower than the health advisory level of 70 ppt set by the EPA. Additionally, in February, EPA published a PFAS Action Plan to address PFAS contaminated sites and prevent future contamination. 

Myers: Are PFAS dangerous?

Evans: There is a wide range of chemicals in PFAS, including PFOA, PFOS, perfluorohexane sulfonic acid (PFHxS) and perfluorononanoic acid (PFNA). These manufactured chemicals are not naturally found in the environment. They are used in industrial and consumer applications due to their ability to withstand water, grease and high temperatures. Between 2000 and 2002, PFOS was voluntarily phased out of production in the U.S. by its primary manufacturer. In 2006, eight major companies voluntarily agreed to phase out their global production of PFOA and PFOA-related chemicals. 

However, prior to phasing PFOA and PFOS out of production, large quantities were released into the environment during the manufacturing processes and have been found to have contaminated the drinking water supplies near current or former manufacturing locations. They remain in soil and groundwater and have a high potential to bioaccumulate in humans, meaning they stay in the body for a long time. EPA has established drinking water health advisories for drinking water to contain a combined maximum total concentration of 70 ppt PFOA and PFOS. Some individual states have established or are considering establishing lower levels.