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Water: Module 3

Basic Course: Key Concepts (Module 3.i)


Module 3. Criteria Development

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  • Water quality criteria protect the designated uses of a water body.

  • Criteria establish acceptable levels of pollutants or conditions in a water body based on scientific data and expert judgment.

  • Each State/Tribe is expected to adopt criteria as part of its water quality standards. States/Tribes typically adopt criteria recommended by EPA, except when site-specific criteria are necessary.


  • A comprehensive set of criteria includes numeric criteria to establish specific threshold values for known entities and narrative criteria to help protect against what can't be precisely measured or where specific risk levels are best determined on a case-by-case basis.

  • Many types of criteria operate together to guide protection of a water body.

  • In their criteria, States/Tribes must address the "priority pollutants" as identified by EPA.

For informational purposes only–Not official statements of EPA policy.

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