An official website of the United States government.

We've made some changes to EPA.gov. If the information you are looking for is not here, you may be able to find it on the EPA Web Archive or the January 19, 2017 Web Snapshot.

Clean Water Act Analytical Methods

Chronic Toxicity - Freshwater WET Methods

Chronic Toxicity to Freshwater Organisms

""This manual describes four- to seven-day methods for estimating the chronic toxicity of effluents and receiving waters to three species. The methods are approved under Clean Water Act section 304(h) and specified at 40 CFR 136.3, Table I–A.

The complete manual and individual method documents are provided. The individual methods are included in the manual.

Errata sheet (2016)


You may need a PDF reader to view files on this page. See EPA’s About PDF page to learn more.