Approved CWA Microbiological Test Methods

The analytical methods promulgated under Clean Water Act Section 304(h) are sometimes referred to as the "304(h)" or "Part 136" methods. The methods measure chemical and biological pollutants in media, such as wastewater, ambient water, sediment, and biosolids (sewage sludge). These various CWA methods are tested in a variety of labs and matrices.

• Approved methods listed by method number
  • Wastewater & Sewage Sludge Methods
  • Ambient Water Methods
• Approved methods listed by analyte (reference tables in 40 CFR 136.3)

Approved Methods Listed by Method Number

• Regulatory History:​
  • Approval of Analytical Methods for Biological Pollutants in Wastewater and Sewage Sludge; Final Rule (March 26, 2007)
  • Clean Water Act Methods Update Rule for the Analysis of Effluent; Final Rule (April 16, 2024)

• Regulatory History:
  • Approval of Analytical Methods for Ambient Recreational Waters; Final Rule (July 21, 2003)
  • Clean Water Act Methods Update Rule for the Analysis of Effluent; Final Rule (April 16, 2024)

Approved Methods Listed by Analyte

• Lists of methods by analyte; from 40 CFR 136.3
  • Table I A: Biological Methods for Wastewater and Sewage Sludge
  • Table I H: Microbiological Methods for Ambient Water