Clean Water Act Analytical Methods

  • Methods Update Rule 22

    The EPA proposed Methods Update Rule 22 to promulgate three new EPA methods into 40 CFR Part 136, and other actions.

    Learn more about the proposed rule

  • Routine Methods Update Rule 2

    On April 16, 2024, the EPA issued a final routine Methods Update Rule 2 under the Clean Water Act.

    View the Final Rule

The EPA publishes laboratory analytical methods (test procedures) that are used by industries and municipalities to analyze the chemical, physical and biological components of wastewater and other environmental samples required by the Clean Water Act.

Other CWA Methods

Optional methods for analyzing wastewater and biosolids (not approved under 40 CFR Part 136):

Alternate Test Procedures

Development of modified EPA methods or new methods

Regulations and Support Documents

Related EPA Programs

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Last updated on April 23, 2025