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.

• Proposed rule (February 19, 2015)
• Final rule (May 18, 2012) (PDF) (89 pp, 1.1 MB, About PDF)
• Final rule (March 26, 2007) (PDF) (14 pp, 248 K)
  Approval of microbial methods for use in wastewater and sewage sludge.
• Final rule (March 12, 2007) (PDF) (50 pp, 469 K)
• Final rule (July 21, 2003) (PDF) (12 pp, 209 K)
  Approval of microbial methods for ambient recreational waters.

Oil and Grease Methods

Method 1664A

• Final rule (May 14, 1999) (PDF) (13 pp, 275 K, About PDF)
  • Guidance on implementation and use (February 2000)
  • Questions and Answers (2004)
• Modifications to Method 1664A
  • Memo: Allowable modifications and unacceptable modifications; and limited use modifications (EPA Region 8 only) (2009)​

Method 1664B

• See May 18, 2012 Methods Update Rule (PDF) (89 pp, 1.1 MB)

Alternative Method: ASTM D7575

• Federal Register Notice (March 6, 2013) (PDF) (5 pp, 235 K)
• Fact Sheet
• Support Documents
  • Guidance for Limited Use ATP Applications for D7575
  • Limited Use ATP Application (MS Word)
  • Limited Use ATP Method Documentation Form
  • Performance Comparison Form - Clean Matrix
  • Performance Comparison Form - Effluent Matrix
  • Oil and Grease ATP Comparison Worksheet (Excel)

Cyanide Methods

• May 18, 2012 Methods Update Rule (PDF) (89 pp, 1.1 MB, About PDF)
• Questions and answers (2004)
• Notice of Administrative Determination (October 6, 2003) (PDF) (2 pp, 166 K)
  EPA determination regarding ferric ferrocyanide
• Final rule (December 30, 1999) (PDF)(10 pp, 48 K)
  Approval of Method OIA-1677

Mercury Methods

• Memo: Mercury in NPDES Permits; Issuance of Method 245.7 (August 23, 2007)
  • Explains use of Methods 1631E and 245.7 as most sensitive for measurement of mercury and appropriate for use in NPDES permits in most cases
• Final rule (October 29, 2002) (PDF) (13 pp, 216 K, About PDF)
  Approval of Method 1631E

Dioxins and Furans

• Final rule (September 15, 1997) (PDF) (49 pp, 634 K, About PDF)
  Approval of Method 1613

Chromium (VI)

• See March 12, 2007 Methods Update Rule (PDF) (50 pp, 469 K, About PDF)
• Questions and Answers: Hexavalent Chromium