Section 303(d) of the federal Clean Water Act (CWA) and the U.S. Environmental Protection Agencys (EPA) implementing regulations direct each state to identify and list waters, known as water quality limited segments (WQLSs), in which current required controls of a specified substance are inadequate to achieve water quality standards. For each WQLS, the State is to either establish a Total Maximum Daily Load (TMDL) for the specified substance that the waterbody can receive without violating water quality standards, or demonstrate that water quality standards are being met. Back River (basin code 02-13-09-01), located in Baltimore County and Baltimore City, MD, was identified on the States list of WQLSs as impaired by nutrients (1996 listing), suspended sediments (1996 listing), chlordane (1996 listing), polychlorinated biphenyls (PCBs) - sediments (1998 listing), zinc (Zn) (1998 listing), fecal coliform (2002 listing) and impacts to biological communities (2002 listing). All impairments were listed for the tidal waters except for the impacts to biological communities, which are listed for the non-tidal region. Code of Maryland Regulations (COMAR) defines the Back River as a fresh waterbody. This report provides an analysis of recent monitoring data, including hardness data, which shows that the aquatic life criteria and designated uses associated with Zn are being met in the Back River. The analyses support the conclusion that a TMDL for Zn is not necessary to achieve water quality standards in this case. Barring the receipt of any contradictory data, this report will be used to support the removal of the Back River from Marylands list of WQLSs for Zn when the Maryland Department of the Environment (MDE) proposes the revision of Marylands 303(d) list for public review in the future. The listings for nutrient, PCBs, suspended sediment, fecal coliform and impacts to biological communities will be addressed separately at a future date. A TMDL for chlordane was completed in 1999.