DPW is accepting comments on: Proposed Plan to Reduce Non-Tidal Harbor Watershed Pollution
Public Comments Due July 16, 2023

This proposed plan presents the City’s approach to addressing the Total Maximum Daily Load (TMDL) for sediment in the non-tidal Baltimore Harbor watershed, established by the U.S. Environmental Protection Agency (EPA). The deadline for comments is Sunday, July 16.  Comments and questions can be sent to  mark.cameron@baltimorecity.gov or 410-396-0732.
Download: Baltimore City’s Implementation Plan

Baltimore’s MS4 Permit

Baltimore City’s storm drain system is regulated by the federal Clean Water Act, specifically, a National Pollutant Discharge Elimination System Municipal Separate Storm Sewer, also known as the MS4 permit. The latest MS4 permit was issued to the City on November 5, 2021. This MS4 permit was developed based on Maryland’s Bay TMDL Phase III Watershed Implementation Plan and the local TMDLs (Total Maximum Daily Loads) associated with waterways in the City. This is the 5th generation of the MS4 permit issued to the City of Baltimore. Specific new conditions are as follows:

  • Street sweeping and inlet cleaning operations initiated under the previous permit must be continued at a level equivalent to 5,170 acres of impervious area restoration,
  • Additional stormwater best management practices (BMPs) must be implemented for an equivalent of 3,696 acres of impervious area restoration by the end of the permit term. A milestone schedule was also established to ensure progress throughout the permit.
  • At least 300 tons of litter and debris must be removed from the City’s storm drain system each year.
  • At least 15 public outreach efforts/year must be conducted related to stormwater pollution and flooding.
  • Monitoring resources may be leveraged by the City by participating in a pooled monitoring program.
  • A comprehensive plan for long-term watershed monitoring and trend monitoring and a Polychlorinated biphenyl source tracking plan must be developed and implemented.
  • Good housekeeping and pollution prevention plans must be developed for City-owned properties.
  • Winter management of de-icing and anti-icing materials must be improved to further reduce chlorides, a pollutant of emerging concern.

The following are documents related to the City’s MS4 Permit:

MS4 Annual Reports

Each year, Baltimore City is required to submit an MS4 Annual Report charting its progress in meeting the terms of the permit.

Financial Assurance Plan

A Financial Assurance Plan (FAP), which demonstrates the City’s financial ability to meet the current and proposed MS4 permit impervious surface area restoration requirements, is required to be submitted every two years.

As part of the MS4 Permit, the EPA approved a "Trash TMDL" for the Middle Branch and Northwest Portions of the Patapsco River, roughly from Harbor Hospital in the south to Ferry Bar Park (Middle Branch) and Tide Point to Canton Waterfront Park (Northwest Portion).

Watershed Assessments

To restore a watershed, there must be a Watershed Plan. The MS4 Permit requires that, by the end of the permit term, Baltimore City shall complete detailed watershed assessments for the entire City. The following is a list of the previous assessments (those noted with an * are too large to upload):

Planning AreaMajor WatershedReport TitleYear
Upper Back RiverBack RiverUPPER BACK RIVER SWAP Vol 1.PDF2008
Biddison RunBack RiverSW Improvement Feasibility & Conceptual Design*2006
Herring RunBack RiverHR Stream Master Plan_071304.pdf2004
Moores RunBack RiverWatershed Restoration Plan*2001
Direct HarborBaltimore HarborWatershed Characterization ReportIn Progress
Masonville CoveBaltimore HarborMasonville Cove-Executive Summary.pdf2014
Watershed 246Baltimore HarborWS 246 HARRIS CREEK SWAP.PDF2010
Watershed 263Baltimore HarborWS263_WS263 Management Plan KCI Aug2006.pdf2006
Lower Jones FallsJones FallsLOWER JONES FALLS SWAP.pdf2008
Western RunJones FallsStream Assessment*2004
Stony RunJones FallsWatershed Restoration Plan*2001
Gwynns FallsGwynns FallsGWYNNS FALLS WATER QUALITY MANAGEMENT PLAN - EXEC. SUMMARY.pdf2004
Powder MillGwynns FallsPowder Mill Targeted Report Final.pdf2004
Maidens ChoiceGwynns FallsWatershed Restoration Plan*2001
Direct HarborBaltimore HarborWatershed Assessment2021
Lower North Branch PatapscoLower North Branch PatapscoWatershed Assessment2021