Municipal Separate Storm Sewer System Permit


The Municipal Separate Storm Sewer System (MS4) Permit is a permit administered by the Maryland Department of the Environment (MDE) in order to carry out the National Pollutant Discharge Elimination System (NPDES) program implemented by the Federal Clean Water Act (CWA). The NPDES program aims to restore and protect the US waterways. In order to meet these requirements, MDE issues MS4 permits with the aim to reduce and eliminate pollution as a result of rainfall runoff.

Frederick County is in its fourth generation of the NPDES MS4 permit since its issuance in 1997, and continues to implement the requirements detailed in the permit. Some of these requirements include:

  • Stormwater Management Program: a program aimed at installing, maintaining, and tracking all stormwater best management practices around the county. 
  • Erosion and Sediment Control Program: a control program aimed limiting pollution associated with construction activities; overseen by the County’s Environmental Compliance Section
  • Illicit Discharge Detection and Elimination Program: an inspection and enforcement program aimed at eliminating or permitting any spills, dumps, or discharges
  • Litter and Floatables Program: a public outreach and education program aimed at reducing problems associated with litter and floatables in our waterways
  • Property Management and Maintenance: a maintenance program aimed at reducing pollutants associated with property maintenance and Industrial Discharge permits of County-owned facilities
  • Public Education
  • Water Quality and Nutrient Reduction and Monitoring: an assessment and monitoring program aimed at meeting wasteload allocations (WLA) and total maximum daily loads (TMDL) delineated by MDE. 
  • Chesapeake Bay Restoration: a restoration program aimed at meeting wasteload allocations (WLA) and total maximum daily loads (TMDL) delineated by MDE
  • Annual Reporting: yearly progress report for implementing permit requirements on a fiscal year basis 

Our MS4 permit and most recent Annual Report submission can be found on our Publications and Resources page.