How is Stormwater Regulated? |

Charles County, Maryland

How is Stormwater Regulated?

How is Stormwater Regulated?

Because polluted stormwater is a national concern, in 1972 Congress mandated amendments to the Federal Clean Water Act (CWA) requiring the implementation of controls designed to prevent stormwater runoff from carrying harmful pollutants into local water bodies. The amendments require certain jurisdictions to obtain National Pollutant Discharge Elimination System (NPDES) Municipal Separate Storm Sewer System permits, also known as MS4 permits.  Under the provisions of the NDPES regulations, stormwater discharges from MS4 systems are considered point sources that require a NPDES permit.   

Visit the Environmental Protection Agency and Maryland’s NPDES Municipal Stormwater Permits for more information.

What is the MS4 Permit?

The MS4 Permit Program was created to reduce and eliminate pollution derived from stormwater runoff in the United States. The main goal of the program is to restore and maintain the chemical, physical, and biological integrity of the nation’s waters.  The Maryland Department of the Environment (MDE) is the state agency responsible or issuing all NPDES permits in Maryland, including MS4 Permits, on behalf of the Environmental Protection Agency. 

MS4 Requirements

MS4 Permits are issued in five (5) year cycles.  Charles County’s current permit was effective December 26, 2014 and expires on December 25, 2019.  Charles County has a medium municipal separate storm water system as defined by the CWA, since it serves a population between 100,000 and 250,000 people.      

Charles County’s MS4 permit requires the County to:

  • Implement comprehensive stormwater management programs for addressing runoff from new and redevelopment projects;
  • Restore urban areas where there is currently little or no stormwater management;
  • Work toward meeting stormwater wasteload allocations for local water resources and the Chesapeake Bay;
  • Map the storm drain system;
  • Monitor urban runoff;
  • Eliminate illicit discharges to the storm drain system;
  • Evaluate current litter control problems associated with discharges to the storm drain system and develop and implement a public outreach education program as needed on a watershed by watershed basis;
  • Continue to implement a public outreach program to reduce stormwater pollutants;
  • Continue to maintain and implement an acceptable erosion and sediment control program
  • Use chemical, biological, and physical monitoring to assess watershed restoration efforts, document BMP effectiveness, or calibrate water quality models for showing progress toward meeting any applicable WLAs developed under EPA approved TMDLs

Charles County NPDES MS4 Annual Reports:

Fiscal Year 2018 NPDES MS4 Annual Report
Fiscal Year 2017 NPDES MS4 Annual Report
Fiscal Year 2016 NPDES MS4 Annual Report
Fiscal Year 2015 NPDES MS4 Annual Report

MS4 Permit Service Area

IMPORTANT PLEASE NOTE:  All publications located within the Planning and Growth Management section of the web site are believed to be accurate as of their posting date. However, they may not be accurate on the day you view them. To verify whether these documents are the most current official document, please contact the division associated with the document in question.