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  2. Clean Water Act Analytical Methods
  3. Approved Microbiological Methods

Approved CWA Microbiological Methods for Ambient Water

Methods approved under Clean Water Act Section 304(h) and published at 40 CFR Part 136.

  • Method 1623.1: Cryptosporidium and Giardia in Water by Filtration/IMS/FA (pdf) (1020.91 KB, January 2012, EPA 816-R-12-001)
  • 1103.2: Escherichia coli (E. coli) in Water by Membrane Filtration Using membrane-Thermotolerant Escherichia coli Agar (mTEC) (pdf) (1.26 MB, September 2023, EPA-821-R-23-009)
  • 1106.2: Enterococci in Water by Membrane Filtration Using membrane-Enterococcus-Esculin Iron Agar (mE-EIA) (pdf) (1.19 MB, September 2023, EPA-821-R-23-007)
  • 1600.1: Enterococci in Water by Membrane Filtration Using membrane-Enterococcus Indoxyl-β-D-Glucoside Agar (mEI) (pdf) (1020.29 KB, September 2023, EPA-821-R-23-006)
  • 1603.1: Escherichia coli (E. coli) in Water by Membrane Filtration Using Modified membrane-Thermotolerant Escherichia coli Agar (Modified mTEC) (pdf) (957.93 KB, September 2023, EPA-821-R-23-008)
  • 1604: Total Coliforms and Escherichia coli in Water by Membrane Filtration Using a Simultaneous Detection Technique (MI Medium) (pdf) (383.57 KB, September 2002, 821-R-02-024)
  • 1622: Cryptosporidium in Water by Filtration/IMS/FA (pdf) (1.01 MB, December 2005, 815-R-05-001)
  • 1623: Cryptosporidium and Giardia in Water by Filtration/IMS/FA (pdf) (937.09 KB, December 2005, 815-R-05-002)

Clean Water Act Analytical Methods

  • PFAS Methods
  • Methods Update Rules
  • Approved Chemical Methods
    • Inorganic Non‑Metals
    • Metals
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  • Approved Microbiological Methods
    • Wastewater & Sewage Sludge
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  • Approved WET Methods
    • Acute
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    • Chronic - Marine/Estuarine
  • Approved Radiochemical Methods
  • Approved Industry-Specific Methods
  • Other CWA Methods: Chemical
  • Other CWA Methods: Microbiological
  • Other CWA Methods: Biosolids
  • Alternate Test Procedures
  • Regulatory History
Contact Us about CWA Analytical Methods
Contact Us about CWA Analytical Methods to ask a question, provide feedback, or report a problem.
Last updated on May 29, 2025
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