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Water: Total Maximum Daily Loads (303d)

Impaired Waters and Total Maximum Daily Loads

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Under section 303(d) of the Clean Water Act, states, territories, and authorized tribes are required to develop lists of impaired waters. These are waters that are too polluted or otherwise degraded to meet the water quality standards set by states, territories, or authorized tribes. The law requires that these jurisdictions establish priority rankings for waters on the lists and develop TMDLs for these waters. A Total Maximum Daily Load, or TMDL, is a calculation of the maximum amount of a pollutant that a waterbody can receive and still safely meet water quality standards.

On December 5, 2013, EPA announced a new collaborative framework for implementing the Clean Water Act Section 303(d) Program with States � A Long-Term Vision for Assessment, Restoration, and Protection under the Clean Water Act Section 303(d) Program. This Vision reflects the successful collaboration among States and EPA, which began in August 2011. While the Vision provides a new framework for implementing the CWA 303(d) Program, it does not alter State and EPA responsibilities or authorities under the CWA 303(d) regulations.

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