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Stormwater Regulation & the County's Efforts


For most urban areas like Montgomery County, what goes into our storm drains ( stormwater) makes its way into our local streams. Those streams are part of larger watersheds that lead to major rivers, like the Potomac River, and eventually the Chesapeake Bay. Because our waters are interconnected and not defined by county or state lines, the federal government regulates everything that goes through storm drain systems. 

The federal government regulates storm drains through a permit process called the Municipal Separate Storm Sewer System Permit Program (AKA the MS4 Permit Program).

Montgomery County has an MS4 Permit that mandates the County to meet certain water quality standards. The Permit is given every 5 years and our latest permit ended February 2015. 



The County's Progress at Cleaning Our Waters

In the most recent Annual Report on our MS4 Permit, the County noted the following progress towards meeting its MS4 Permit Requirements:


Watershed Restoration Planning and Implementation 

The Department of Environmental protection (DEP) is the lead agency for projects to reduce stormwater runoff impacts. During Fiscal Year 2014, DEP:

  • Had stormwater restoration projects in design or construction that will treat the runoff from over 3,976 acres of impervious areas.

  • Completed watershed studies, including identifying restoration projects within the Seneca Creek, Patuxent River, Lower Monocacy, and Upper and Lower Potomac Direct watersheds.

  • Provided stormwater management to over 12 acres of impervious area through the RainScapes Program, which supports and constructs small scale residential stormwater management practices for both single lots and neighborhoods.

  • Watershed restoration projects are monitored to assess achievement of stream habitat and biological improvement.


Image of a stormwater management pondThe new pond installed at the National Institutes of Health captures and slows stormwater and removes pollutants.


Reducing Pollution

DEP is the lead agency for enforcement of water quality laws that reduce pollution to our waterways. During Fiscal Year 2014, DEP:

  • Assessed 154 storm drain outfalls in the Little Falls watershed for illegal discharges.

  • Discovered 3 illegal discharges through the storm drain system, and identified and remediated the sources.

  • Responded to 264 water quality related complaints resulting in 68 enforcement actions.


DEP also partnered with other County agencies to reduce pollution.

  • DEP, the Department of General Services (DGS) and the Department of Transportation (DOT) work together to reduce pollution from County Highway Depots. During FY14, the DGS upgraded the used oil handling area at the Brookville Depot. In addition, all County Depots are now routinely swept.

  • All County industrial facilities submitted Notice of intents (NOIs) for coverage under the MDE’s new General Discharge permit for Stormwater Associated with Industrial Activities, and updated their Stormwater Pollution prevention Plans.

  • The DEP and the DOT jointly funded street sweeping that covered 8,413 curb miles, removing 1,387 tons of street pollutants

  • The DOT removed 217 tons of roadway pollutants from storm drain inlets and pipes through its infrastructure maintenance program.

  • The Department of Permitting Services (DPS) conducted 18,151 erosion and sediment control inspections, resulting in 250 Notices of Violation and 160 civil citations during construction of development projects.


Image of a street sweeperCounty contractors removed 916 tons of roadway pollutants from County Streets.


Meeting County Total Maximum Daily Loads (TMDLs)

The MS4 Permit requires implementation plans showing how the County will achieve pollutant load reductions to meet waste load allocations for any Environmental Protection Agency approved Total Maximum Daily Load (TMDL). Watershed Implementation Plans for all County TMDLs approved as of 2010 can be found in the Countywide Implementation Strategy. 

DEP made progress towards meeting the Chesapeake Bay TMDL by reducing nitrogen and phosphorous through watershed restoration and other stormwater best management practices. In Fiscal Year 14, County pollutant reductions achieved 4.4% of the nitrogen pollution reduction goal required to meet County’s share of Chesapeake Bay TMDL, and 20% of the phosphorous pollution goal. 

Learn more about Total Maximum Daily Loads


Maintaining Existing Stormwater Management (Facilities)

DEP oversaw triennial inspection of 1,143 stormwater management facilities, and oversaw maintenance and repairs on 1,871 facilities. DEP also began contracting for routine maintenance of publically owned ESD practices.


Educating and Engaging Communities

The DEP is the lead for implementing the Public Outreach and Education Workplan. The workplan was developed in the County Coordinated Implementation Strategy to highlight targeted restoration and outreach activities for the County to develop and refine. During Fiscal Year 2014, DEP :

  • Continued to expand outreach and education to increase stormwater awareness by reaching out to over 18,000 residents at nearly 150 events.

  • Continued the Stream Stewards program to train County volunteers to further watershed outreach in communities. Volunteers donated nearly 3,000 hrs in FY16 which represents a total service value of $72,000 to the County.

  • Supported local watershed groups through capacity building and training workshops.

  • Focused efforts to provide outreach to culturally diverse communities.

  • Continued the Pet waste program, working with homeowner’s associations to install pet waste stations in high use areas, collecting 7,811 lbs of pet waste.

  • Continued the storm drain art and marking program to raise stormwater pollution awareness. 

  • Continued the “Caching the Rain” geocaching trail with a stormwater pollution focus.

  • Developed a watershed restoration and outreach grant program, awarding 13 community grants in the amount of $370,756 to local nonprofits to improve water quality.


Image of the Geneva Day School conservation landscapingVolunteers at the Geneva Day School  Train the Trainer Workshop


Montgomery County Public Schools

Montgomery County Public Schools (MCPS) is an MS4 Co-Permittee and thus required to implement and report on programs to address runoff pollution. MCPS is responsible for maintaining many of the Stormwater Best Management Practices on their sites and for implementing stormwater pollution prevention programs at the MCPS Bus Depots.

MCPS participates with DEP to identify and implement stormwater retrofit opportunities, including Environmental Site Design (ESD) practices on school property. MCPS is aggressively incorporating ESD practices into school building renovations.


Reducing Litter

In May 2011, the County adopted a carry-out bag fee to increase awareness about the problem of litter in our local streams and to offset costs of clean up for those who chose to use disposable bags. The law went into effect in January 2012. DEP is the lead agency for regional efforts to reduce trash and litter to the Potomac River and its tributaries. During FY16, DEP:

  • Worked across jurisdictions to encourage the development and signing of the Anacostia Accord

  • Worked with volunteers for litter clean ups in streams and at stormwater management ponds, collecting over 3,000 lbs of trash.

  • Awarded a community based social marketing contract to develop an outreach campaign in the White Oak neighborhood in Silver Spring to discourage littering and encourage proper trash disposal.

  • Distributed over 40,000 reusable bags to the community.

  • Launched an enhanced outreach campaign for the Carryout Bag tax targeted to retailers, restaurants, and the general public coordinating with the Public Information Office, Department of Finance.

  • Continued tracking the results of the carryout bag law program on reducing plastic bags in the environment.


Image of a Stream Steward educating a Montgomery County residentThe Stream Steward program trains volunteers to serve as ambassadors for the DEP. 



DEP is the lead agency for the monitoring required in the MS4 Permit. The MS4 permit requires the County to conduct monitoring to determine how well stormwater management practices reduce stormwater quantity and pollution. DEP is constructing several small scale stormwater management practices in the Breewood tributary, a small subwatershed of the Anacostia.

The County currently monitors biological, water chemistry, and physical conditions in the Breewood tributary to document pre-restoration conditions. DEP also monitors the physical condition of streams in the Clarksburg Special Protection Area (SPA) to determine the effectiveness of stormwater management meeting the criteria of the Maryland Stormwater Design Manual. DEP monitors County streams to assess stream biological and habitat conditions.



The County reported that $51,728,358 was budgeted to meet the MS4 Permit required programs. The majority of these funds are provided through the Montgomery County Water Quality Protection Charge (WQPC). In FY14, the WQPC provided $24,101,094.


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