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Water: Module 4

Basic Course: Key Concepts (Module 4.a)

Introduction: Weighing Uses Against Degradation of Quality

Module 4. Antidegradation Requirements

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Under the Clean Water Act (CWA), once the existing uses of a water body have been established—by evaluating the water's quality relative to uses already attained—a State/Tribe must maintain the level of water quality that has been identified as being necessary to support those existing uses.

But what if the water quality is better than what is necessary to support the existing uses? That is, what if progress has been made toward attaining the CWA 101(a) goal uses?

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Question. Can the State/Tribe then allow a degradation of water that is better than that necessary to protect CWA 101(a) uses? What if the degradation would provide economic or social development opportunities or other benefits to the State or Tribe?

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The answer is yes. However, in order to effectively address the considerations involved in making such decisions, EPA's regulations require the State/Tribe to have established an antidegradation policy as part of its water quality standards.


Video Clip View a 2-minute video clip from the classroom session about EPA and States/Tribes working together on water quality.

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

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