Skip to main content

EPA announced on December 19 a new validated method for detecting per- and polyfluoroalkyl substances (PFAS). Method 533 focuses on “short-chain” PFAS and can identify 25 different substances in water, including 11 that were not previously achievable. This new method complements the already existing Method 537.1 which itself covers 18 PFAS. In total, 29 unique PFAS can be measured in drinking water using these two methods.

This completes one of the short-term action items the agency laid out in its PFAS Action Plan released in February of this year. The new method clarifies the requirements of a provision in the 2020 National Defense Authorization Act that mandates the next round of contaminant monitoring under the Unregulated Contaminant Monitoring Rule (UCMR) to include all unregulated PFAS that have a validated drinking water measurement method. With such methods now validated for 29 PFAS, each will be subject to the next round of UCMR monitoring, in addition to as many as 30 other unregulated contaminants that EPA may make subject to screening.