Total Maximum Daily Load (TMDL) is a term used to describe the amount of pollution a stream can receive and still meet water quality standards. Water quality standards are regulations based on federal or state law that set numeric or narrative limits on pollutants. TMDLs are required for water bodies that are determined to be impaired. The Virginia TMDL program was historically governed by a federal court order Consent Decree that laid out a schedule for TMDL development through 2010 for waters identified as impaired by 1998. For all other water bodies, TMDL development is generally scheduled within 8 to 12 years of finding the water body impaired.
The Roanoke River watershed, which includes Salem, currently has 3 TMDLs: PCB, Bacteria, and Benthic (sediment).