The EPA regularly promulgates updates to the table of approved Clean Water Act monitoring methods at 40 CFR 136.3. This methods update rule (MUR) considers adding new methods and analytes to the 40 CFR part 136.3 tables. These include multi-laboratory validated EPA methods for per- and polyfluorinated alkyl substances (PFAS), a method defined parameter for adsorbable organic fluorine, the promulgation of which in 40 CFR 136.3 will support the Organic Chemicals, Plastics, and Synthetic Fibers Effluent Limitations Guidelines and Standards (40 CFR part 414) rulemaking to address PFAS discharges from facilities manufacturing PFAS. The MUR also considers adding a method for poly-chlorinated biphenyl (PCB) congeners (a more accurate substitute for PCB Aroclors). The rule may also include other parameters proposed by Voluntary Consensus Standard Bodies (VCSB) as is consistent with the National Technology Transfer Act. These VCSB methods are most likely proposing a PFAS method, peracetic acid, and hydrogen peroxide; assuming the VCSB provides adequate validation data. The EPA is not considering method revisions or Alternate Test Procedures that would be addressed more routinely in a routine MUR.