The Environmental Protection Agency (EPA) is indicating changes to clean water test procedures under EPA's National Pollutant Discharge Elimination System (NPDES) permit program for analyzing the chemical, physical, and biological properties of wastewater and other samples.

The approved methods in 40 CFR part 136 are proposed to be updated on a regular basis by EPA.

• The first category is updated versions of EPA methods currently approved in 40 CFR part 136.
• The second is new or revised methods published by the VCSBs (Voluntary Consensus Standards Body) or the USGS (United States Geological Survey) that are similar to methods previously adopted as EPA-approved methods in 40 CFR part 136.

EPA is proposing the adoption of these revisions to improve data quality, update methods to keep current with technology advances, and provide the regulated community with greater flexibility.

Approval of the EPA membrane filtration methods 1103.2, 1106.2, 1600.1, and 1603.1

• E. coli. Method 1103.2
• Enterococci. Method 1106.2
• Enterococci. Method 1600.1
• E. coli. Method 1603.1

These methods describe a membrane filter (MF) procedure for the detection and enumeration of either enterococci or Escherichia coli bacteria by their growth after incubation on selective media and provide a direct count of bacteria in water samples based on the development of colonies on the surface of the membrane filter.

Changes to the ASTM method:

ASTM added text to the appropriate method scope sections to indicate that the method was developed in accordance with the "Decision on Principles for the Development of International Standards, Guides and Recommendations" issued by the World Trade Organization Technical Barriers to Trade Committee.

Dissolved Oxygen, Hydrogen Ion (pH), Metals Series Surfactants, Residue, filterable and nonfilterable, Cyanide—Free, Cyanide—Total, Organic Carbon – these ASTM get changed, refer to the document link below.