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Method Update Rule (MUR) for Laboratories

Revisions to lab methods for non-potable water and drinking water, adding to fields of accreditation (FoAs) for proficiency testing, and how these apply to your lab’s accreditation.

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In 2025, the TCEQ Laboratory Accreditation Program revised its fields of accreditation (FoAs) to include the following analytical methods:

Drinking Water

EPA 533

  • Hexafluoropropylene oxide dimer acid (HFPO-DA) (GenX)
  • Perfluorobutane sulfonate (PFBS)
  • Perfluorohexane Sulfonate (PFHxS)
  • Perfluorononanoate (PFNA)
  • Perfluorooctanesulfonic Acid (PFOS)
  • Perfluorooctanoic Acid (PFOA)

EPA 337.1 Rev. 1 and 2

  • Hexafluoropropylene oxide dimer acid (HFPO-DA) (GenX)
  • Perfluorobutane sulfonate (PFBS)
  • Perfluorohexane Sulfonate (PFHxS)
  • Perfluorononanoate (PFNA)
  • Perfluorooctanesulfonic Acid (PFOS)
  • Perfluorooctanoic Acid (PFOA)

This revision incorporates methods from the most recent Method Update Rule (MUR) and adds methods that the TCEQ Drinking Water Program requested.  Find the additional methods and analytes in: Analytes and Methods for Water Quality Testing (Effective 01012025)

Applying to Add to Your Labs’ Accreditation

To add any of the additional parameters listed in Appendix A (above) to an existing scope of accreditation for your lab, submit the following, depending on whether your lab is accredited as a Primary Lab or Secondary:

Primary Labs

  • An amended application
  • Applicable FoA sheets
  • A $250.00 administrative fee
  • Associated documentation including:
    • Standard operating procedures
    • Demonstrations of capability and method detection limit studies
    • Applicable proficiency testing (PTs) results for all parameters being added [that are also fields of proficiency testing (FoPTs)]

Secondary Labs

  • An amended application
  • Applicable FoA sheets
  • A $250.00 administrative fee

Note:our laboratory will not have to pay the $250 administrative fee to change the scope of accreditation if it is done as part of the laboratory’s annual renewal. Any applicable category fees will still apply. If your laboratory has submitted two passing PT results for EPA Methods 533 or 537.1 after July 1, 2024, you are not required to submit PT results for EPA Methods 533 and 537.1.

TCEQ will review applications in the order they are received. Laboratories submitting incomplete or inaccurate applications will be notified of the deficiencies and will need to submit a corrected application. Corrected applications will be placed in the queue based on the date received.

For application forms and where to send them, see our NELAP Accreditation webpage.

Need More Information?

For questions about what data will be accepted, contact the TCEQ Water Quality Division at 512-239-4539 or wqap@tceq.texas.gov.

For questions about the two new Drinking Water methods, contact the quality assurance officer for the Water Supply Division at 512-239-4691 or PDWS@tceq.texas.gov/a>.

For more information about the EPA methods see the EPA Methods Update Rules