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  1. Home
  2. Clean Water Act Analytical Methods

How to Get Methods Approved

The Clean Water Act requires the EPA to establish testing procedures for analysis of pollutants through a formal notice and comment rulemaking process. These testing methods must be used for measuring pollutants for NPDES permit applications and any NPDES reporting requirements. The Office of Science and Technology (OST) within the EPA’s Office of Water (OW) is responsible for developing, reviewing and promulgating these methods as well as developing alternatives to existing methods.

Methods Update Rules

Because promulgating methods through individual rulemakings would be very resource-intensive, the EPA periodically combines new methods and modifications to existing methods into a single package – a proposed “Methods Update Rule” (MUR). Once the EPA promulgates final rules, it codifies the approved methods at 40 CFR Part 136. These approved methods must be used for determining compliance with pollutant discharge limitations.
  • Regulatory history - Methods Update Rules

For its MURs, the EPA considers new or revised methods from two major sources. One is the Agency’s Alternate Test Procedure (ATP) program. Under this program, method developers submit an application for a proposed new method or modification to an approved Part 136 method – an “alternative method” – directly to OST for evaluation for nationwide use. There are established, formal protocols for the ATP program that lay out specific requirements for submitting methods/modifications for consideration.

VCSB Methods

The second major source for new or revised methods is those methods that are adopted by a voluntary consensus standards body (VCSB) such as ASTM International and Standard Methods, or another government agency such as the United States Geological Survey. VCSBs may submit methods and modifications to OST under the provisions of the National Technology Transfer and Advancement Act (NTTAA). The NTTAA requires the EPA to adopt methods approved by VCSBs, unless doing so would be inconsistent with applicable laws or is otherwise impractical. When VCSBs or other government agencies submit adopted methods for consideration, they must include the method in its final form, documentation that it has been approved/published by that VCSB or agency, the validation study plan, and the validation study report, including data and analysis that supported the method’s development and adoption. The VCSB or agency must comply with its own internal method testing criteria (e.g., ASTM D2777).

Clean Water Act Analytical Methods

  • PFAS Methods
  • Methods Update Rules
  • Approved Chemical Methods
    • Inorganic Non‑Metals
    • Metals
    • Organic
  • Approved Microbiological Methods
    • Wastewater & Sewage Sludge
    • Ambient Water
  • Approved WET Methods
    • Acute
    • Chronic - Freshwater
    • Chronic - Marine/Estuarine
  • Approved Radiochemical Methods
  • Approved Industry-Specific Methods
  • Other CWA Methods: Chemical
  • Other CWA Methods: Microbiological
  • Other CWA Methods: Biosolids
  • Alternate Test Procedures
  • Regulatory History
Contact Us about CWA Analytical Methods
Contact Us to ask a question, provide feedback, or report a problem.
Last updated on May 1, 2025
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