Clean Water Act Analytical Methods

CWA Methods Regulatory History

Federal Register notices and related documents for approved and alternative methods

Methods Update Rules

EPA periodically updates the list of approved methods to reflect advances in technology, refine quality assurance and quality control requirements, and provide entities more choices of approved compliance monitoring methods.

  • Final rule (December 2016)
  • Final rule (May 18, 2012)
  • Final rule (March 26, 2007)
    Approval of microbial methods for use in wastewater and sewage sludge.
  • Final rule (March 12, 2007)
  • Final rule (July 21, 2003)
    Approval of microbial methods for ambient recreational waters.

Oil and Grease Methods

Method 1664A

Method 1664B

Alternative Method: ASTM D7575

Final Decision on use of ASTM Method D7575 for measurement of oil and grease
  • Federal Register Notice (March 6, 2013)
  • Support Documents
    • Limited Use ATP Application
    • Limited Use ATP Method Documentation Form
    • Performance Comparison Form - Clean Matrix
    • Performance Comparison Form - Effluent Matrix
    • Oil and Grease ATP Comparison Worksheet
    • Fact sheet
    • Guidance for Limited Use ATP Applications for D7575

Cyanide Methods

Mercury Methods

Dioxins and Furans

  • Final rule (September 15, 1997)
    Approval of Method 1613

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