Maryland’s NPDES Municipal Separate Storm Sewer System (MS4) Permits

​MS4 Permits Key Part of Maryland’s Chesapeake Bay Restoration Plan

​The Maryland Department of the Environment (MDE) has proposed a series of municipal stormwater permits to advance Chesapeake Bay restoration while reducing flooding and making communities more resilient to the effects of climate change.

On October 23, 2020 MDE issued draft municipal separate storm sewer system (MS4) permits for Baltimore City and Anne Arundel, Baltimore, and Montgomery counties. The draft permits build upon and improve pollution prevention under current permits and require local jurisdictions to not only keep pace but do more to help Maryland meet its Chesapeake Bay total maximum daily load (TMDL) requirements. The five-year permits are issued under the federal Clean Water Act.

When it rains, stormwater washes excess nutrients, chemicals, and dirt from impervious surfaces, such as buildings, roads, and parking lots into local waters and the Chesapeake Bay. Excess stormwater runoff can also flood local communities, scour sediment from waterways, and degrade the health of stream systems. MDE’s four draft permits will continue the state’s robust work to reduce nutrient and sediment pollution from stormwater as part of a larger effort that requires all sectors – including sewage treatment plants, septic systems, and agriculture – in Maryland and the surrounding region to do their fair share to restore and protect the Chesapeake Bay. The MS4 permits require local jurisdictions to restore impervious surface areas that have little or no stormwater treatment with green infrastructure and other techniques at a pace and scale that they can achieve through continued commitment, collaboration, and innovation. The permits are a key element of Maryland’s Chesapeake Bay restoration plan.

Maryland’s eleven phase I urban jurisdictions have established themselves as national leaders in reducing stormwater pollution by collectively investing $685 million in clean water infrastructure and restoring 35,000 impervious acres under prior permits. The MS4 permits proposed for Baltimore City and Anne Arundel, Baltimore, and Montgomery counties require in total another 11,000 impervious acres for restoration in the next five years. This restoration work continues to advance innovations such as pay-for-performance contracting, public-private partnerships, and new technologies. The permits also include new incentives for climate resiliency and green infrastructure projects.

To help support this work, in the fiscal year beginning in July 2019, MDE’s Water Quality Finance Administration guaranteed $108.3 million in low interest loans to counties and local governments for stormwater restoration projects, and another $213.2 million in low interest loans are pending for planned projects. The Chesapeake and Atlantic Coastal Bays Trust Fund awarded an additional $36.5 million in grants to stormwater programs for restoration projects. Maryland continues to push for additional federal funding for local stormwater projects – especially for those that increase climate resiliency in underserved communities and for those that help sustain our Chesapeake Bay restoration efforts for decades to come. 

In addition to providing financial and technical support, MDE has helped to streamline and improve the agency’s permitting process for local stream and wetland restoration projects. Since 2016, the number of permit applications for restoration projects has increased by 50% and the projects have doubled in size. For each restoration project, MDE ensures that it is done in an ecologically sound manner that minimizes impacts to other valued resources, for a more holistic approach to watershed health.

“Maryland’s proposed municipal stormwater permits are essential to our comprehensive, science-based plan for restoring the Chesapeake Bay. By working with local jurisdictions to prevent stormwater pollution and embrace nature-based solutions for healthy watersheds, we can reduce flooding, increase climate resiliency, and help to green and grow the state’s economy.”

Maryland Environment Secretary, Ben Grumbles.​

Notice of Proposed Settlement - Prince George's County (January 29, 2021)

 

​​The Maryland Department of the Environment and the Prince George’s County Department of Environmental Protection have reached tentative agreement on a consent decree to be filed in Prince George’s County Circuit Court resolving issues with the county’s performance pursuant to the National Pollutant Discharge Elimination System (NPDES) Municipal Separate Storm Sewer System (MS4) permit issued January 2, 2014.  The five-year permit expired on January 1, 2019.  

While a public comment period is not required by Maryland law as part of the review and approval of such a settlement, the parties are aware of public interest in this and other county MS4 stormwater permits.  Accordingly, the Department of the Environment is distributing copies of the tentative settlement to interested parties and making it available on the Department’s web page.  The tentative settlement can be viewed here:

Comments will be accepted through March 2, 2021.  Those comments may be submitted electronically to Raymond.bahr@maryland.gov or mailed to the attention of Raymond Bahr, Suite 400, Maryland Department of the Environment, 1800 Washington Boulevard, Baltimore, MD  21230.  

The consent decree imposes a $475,000 penalty for failure to complete all of the restoration work required by the 2014 permit.  The penalty can be satisfied through the construction of one or more Department-approved Supplemental Environmental Projects by December 31, 2024.  In addition, the decree requires that the restoration work remaining under the terms of the 2014 MS4 permit be completed in the same timeframe.  The settlement calls for additional penalties for failure to meet interim goals.  

Prince George’s County initiated efforts to address urban stormwater runoff well before the Chesapeake Bay Total Maximum Daily Load (TMDL) was established in 2010 and has been diligent in its efforts.  This consent decree requires the county to complete the impervious surface restoration work that remains to be performed notwithstanding the expiration of the 2014 permit.

"We appreciate Prince George’s County's commitment to improved environmental performance under its state permit and collaboration on the consent decree, including provisions on penalties, schedules, and supplemental environmental projects”, said Secretary Ben Grumbles.  “Preventing stormwater pollution can be challenging but it's important for local water quality and the Chesapeake Bay and the state will continue to enforce its laws and provide assistance to counties and communities."


Notice of Tentative Determination to Issue Stormwater Permit to Anne Arundel County (October 23, 2020)

 

The Maryland Department of the Environment, Water Science Administration (Department) has reached a tentative determination to issue a National Pollutant Discharge Elimination System permit to Anne Arundel County to Discharge from their Large Municipal Separate Storm Sewer Systems (Discharge Permit No. 20-DP-3316, NPDES No. MD0068306).  The Department has drafted a permit designed to comply with the United States Environmental Protection Agency’s (EPA) regulations and to control stormwater pollutant discharges into, though, or from the County’s storm sewer system.  The permit is issued for five years.

Under the conditions of the permit, Anne Arundel County is required to possess the legal authority to control storm sewer system pollutants, maintain its storm sewer system, monitor stormwater discharges, and develop and implement comprehensive management programs.  The permit also sets new requirements for impervious area treatment, property management and maintenance, and options for comprehensive water quality monitoring.  The County is also required to develop and implement plans to address wasteload allocations established under EPA approved or established total maximum daily loads.  Penalties for failure to comply with the terms of the permit are provided.

The draft permit and fact sheet can be viewed here:

MS4 Guidance Includes:

The Department used the following documents to help assess the physical and financial capacity of Anne Arundel County to meet restoration goals proposed in the permit. These analyses were submitted in July 2019 and April 2020 and some of the information contained within do not incorporate continued program activity and updates. 

These analyses were based on instructions and spreadsheets sent to the County.  These instructions may be found here: 

Hard copies of the documents may also be obtained directly from the Department at a cost of 36¢ per page.  Written comments concerning the tentative determination will be considered in the preparation of a final determination if submitted to the Department on or before January 21, 2021.  This comment period already incorporates the additional 60-day period provided in §1–606(d)(1)(ii) of the Environment Article.  Comments should be directed to the Maryland Department of the Environment, Water and Science Administration, 1800 Washington Blvd., Ste. 440, Baltimore, MD 21230-1708, Attn: Raymond Bahr, Sediment, Stormwater, and Dam Safety Program, or email to Raymond.Bahr@Maryland.gov.

The Department held a public hearing concerning this tentative determination on Tuesday, November 17, 2020 through an online webinar.  The transcript and video of the hearing are available below.  Please understand that due to the nature of the voice-to-text software used to generate the transcript, there may be some errors in the translation.

Any questions regarding the proposed permit should be directed to Raymond Bahr at Raymond.Bahr@Maryland.gov or by telephone at 410-537-3543, between the hours of 8:00 AM and 5:00 PM, Monday through Friday.  

Notice of Tentative Determination to Issue Stormwater Permit to Baltimore County (October 23, 2020)

 


The Maryland Department of the Environment, Water Science Administration (Department) has reached a tentative determination to issue a National Pollutant Discharge Elimination System permit to Baltimore County to Discharge from their Large Municipal Separate Storm Sewer Systems (Discharge Permit No. 20-DP-3317, NPDES No. MD0068314).  The Department has drafted a permit designed to comply with the United States Environmental Protection Agency’s (EPA) regulations and to control stormwater pollutant discharges into, through, and from the County’s storm sewer system.  The permit is issued for five years.

Under the conditions of the permit, Baltimore County is required to possess the legal authority to control storm sewer system pollutants, maintain its storm sewer system, monitor stormwater discharges, and develop and implement comprehensive management programs.  The permit also sets new requirements for impervious area treatment, property management and maintenance, and options for comprehensive water quality monitoring.  The County is also required to develop and implement plans to address wasteload allocations established under EPA approved or established total maximum daily loads.  Penalties for failure to comply with the terms of the permit are provided.

The draft permit and fact sheet can be viewed here:

MS4 Guidance Includes:

The Department used the following documents to help assess the physical and financial capacity of Baltimore County to meet restoration goals proposed in the permit. These analyses were submitted in June 2019 and April 2020 and some of the information contained within do not incorporate continued program activity and updates. 

These analyses were based on instructions and spreadsheets sent to the County.  These instructions may be found here: 

Hard copies of the documents also may be obtained directly from the Department at a cost of 36¢ per page.  Written comments concerning the tentative determination will be considered in the preparation of a final determination if submitted to the Department on or before January 21, 2021.  This comment period already incorporates the additional 60-day period provided in §1–606(d)(1)(ii) of the Environment Article.  Comments should be directed to the Maryland Department of the Environment, Water and Science Administration, 1800 Washington Blvd., Ste. 440, Baltimore, MD 21230-1708, Attn: Raymond Bahr, Sediment, Stormwater, and Dam Safety Program, or email to Raymond.Bahr@Maryland.gov. 

The Department held a public hearing concerning this tentative determination on Thursday, November 19, 2020 through an online webinar.  The transcript and video of the hearing are available below.  Please understand that due to the nature of the voice-to-text software used to generate the transcript, there may be some errors in the translation.

Any questions regarding the proposed permit should be directed to Raymond Bahr at Raymond.Bahr@Maryland.gov or by telephone at 410-537-3543, between the hours of 8:00 AM and 5:00 PM, Monday through Friday. 

Notice of Tentative Determination to Issue Stormwater Permit to Baltimore City (October 23, 2020)

 

​The Maryland Department of the Environment, Water Science Administration (Department) has reached a tentative determination to issue a National Pollutant Discharge Elimination System permit to Baltimore City to Discharge from their Large Municipal Separate Storm Sewer Systems (Discharge Permit No. 20-DP-3315, NPDES No. MD0068292).  The Department has drafted a permit designed to comply with the United States Environmental Protection Agency’s (EPA) regulations and to control stormwater pollutant discharges into, through, and from the City’s storm sewer system.  The permit is issued for five years.​

Under the conditions of the permit, Baltimore City is required to possess the legal authority to control storm sewer system pollutants, maintain its storm sewer system, monitor stormwater discharges, and develop and implement comprehensive management programs.  The permit also sets new requirements for impervious area treatment, property management and maintenance, and options for comprehensive water quality monitoring.  The City is also required to develop and implement plans to address wasteload allocations established under EPA approved or established total maximum daily loads.  Penalties for failure to comply with the terms of the permit are provided.​

The draft permit and fact sheet can be viewed here:

MS4 Guidance Includes:

The Department used the following documents to help assess the physical and financial capacity of Baltimore City to meet restoration goals proposed in the permit. These analyses were submitted in October 2019 and April 2020 and some of the information contained within do not incorporate continued program activity and updates. 

These analyses were based on instructions and spreadsheets sent to the City.  These instructions may be found here: 

Hard copies of the documents may also be obtained directly from the Department at a cost of 36¢ per page.  Written comments concerning the tentative determination will be considered in the preparation of a final determination if submitted to the Department on or before January 21, 2021.  This comment period already incorporates the additional 60-day period provided in §1–606(d)(1)(ii) of the Environment Article.  Comments should be directed to the Maryland Department of the Environment, Water and Science Administration, 1800 Washington Blvd., Ste. 440, Baltimore, MD 21230-1708, Attn: Raymond Bahr, Sediment, Stormwater, and Dam Safety Program, or email to Raymond.Bahr@Maryland.gov. 

The Department held a public hearing concerning this tentative determination on Friday, November 20, 2020 through an online webinar.  The transcript and video of the hearing are available below.  Please understand that due to the nature of the voice-to-text software used to generate the transcript, there may be some errors in the translation.

Any questions regarding the proposed permit should be directed to Raymond Bahr at Raymond.Bahr@Maryland.gov or by telephone at 410-537-3543, between the hours of 8:00 AM and 5:00 PM, Monday through Friday.  

Notice of Tentative Determination to Issue Stormwater Permit to Montgomery County (October 23, 2020)

 

The Maryland Department of the Environment, Water Science Administration (Department) has reached a tentative determination to issue a National Pollutant Discharge Elimination System permit to Montgomery County to Discharge from their Large Municipal Separate Storm Sewer Systems (Discharge Permit No. 20-DP-3320, NPDES No. MD0068349).  The Department has drafted a permit designed to comply with the United States Environmental Protection Agency’s (EPA) regulations and to control stormwater pollutant discharges into, through, and from the County’s storm sewer system.  The permit is issued for five years.

Under the conditions of the permit, Montgomery County is required to possess the legal authority to control storm sewer system pollutants, maintain its storm sewer system, monitor stormwater discharges, and develop and implement comprehensive management programs.  The permit also sets new requirements for impervious area treatment, property management and maintenance, and options for comprehensive water quality monitoring.  The County is also required to develop and implement plans to address wasteload allocations established under EPA approved or established total maximum daily loads.  Penalties for failure to comply with the terms of the permit are provided.

The draft permit and fact sheet can be viewed here: 

MS4 Guidance Includes:

The Department used the following documents to help assess the physical and financial capacity of Montgomery County to meet restoration goals proposed in the permit. These analyses were submitted in May 2019 and March 2020 and some of the information contained within do not incorporate continued program activity and updates. 

These analyses were based on instructions and spreadsheets sent to the County.  These instructions may be found here: 

Hard copies of the documents also may be obtained directly from the Department at a cost of 36¢ per page.  Written comments concerning the tentative determination will be considered in the preparation of a final determination if submitted to the Department on or before January 21, 2021.  This comment period already incorporates the additional 60-day period provided in §1–606(d)(1)(ii) of the Environment Article.  Comments should be directed to the Maryland Department of the Environment, Water and Science Administration, 1800 Washington Blvd., Ste. 440, Baltimore, MD 21230-1708, Attn: Raymond Bahr, Sediment, Stormwater, and Dam Safety Program, or email to Raymond.Bahr@Maryland.gov. 

The Department held a public hearing concerning this tentative determination on Monday, November 16, 2020 through an online webinar.  The transcript and video of the hearing are available below.  Please understand that due to the nature of the voice-to-text software used to generate the transcript, there may be some errors in the translation.

Any questions regarding the proposed permit should be directed to Raymond Bahr at Raymond.Bahr@Maryland.gov or by telephone at 410-537-3543, between the hours of 8:00 AM and 5:00 PM, Monday through Friday.  

NPDES Phase I Permits

 

​You can view background information on each jurisdiction by clicking on the municipality's name in the chart below. Initial permits, current permits, and links to the agency responsible for administering each local permit are also accessible by clicking on the respective links below.

 

Initial Permit Issued Current Permit Issued Local Agency Responsible for Annual Reporting

Large Jurisdictions

Anne Arundel County

12/02/1993

02/12/2014

Dept. of Public Works / Watershed Protection and Restoration

Baltimore County

11/17/1994

12/23/2013

Dept. of Environmental Protection & Sustainability (EPS) / NPDES

Baltimore City

11/17/1993

12/27/2013

Dept. of Public Works

Montgomery County

03/15/1996

02/16/2010

Dept. of Environmental Protection

Prince George’s County

11/17/1993

01/02/2014

Dept. of Environment

Medium Jurisdictions

Carroll County

05/30/1995

12/30/2014

Land Use, Planning & Development

Charles County

05 /01/1997

12/26/2014

Planning & Growth Management

Frederick County

11/15/1994

12/30/2014

Sustainable Development - Watershed Management

Harford County

05/17/1994

12/30/2014

Dept. of Public Works - Water Resources

Howard County

04/17/1995

12/18/2014

Dept. of Public Works / Stormwater Management Division

State Storm Drain Systems

State Highway Administration

01/08/1999

10/09/2015

Office of Environmental Design

Summary of Local Requirements
 
NPDES municipal stormwater permits require the jurisdictions to develop comprehensive programs to reduce storm drain system pollution to the MEP. Typical NPDES stormwater permit conditions require jurisdictions to: 
  • Legal Authority: provide certification from appropriate legal counsel that adequate authority exists to control discharges from the municipal storm drain system
  • Source Identification: map storm drain pipes and best management practices (BMPs), land use, impervious cover, and watershed restoration projects in geographical information system (GIS) format
  • Management Programs: implement erosion and sediment control, stormwater management, illicit connection detection and elimination, and public education and outreach programs
  • Watershed Assessment: evaluate all urban watersheds thoroughly regarding water quality and develop goals and action plans for restoration,
  • Restoration Projects: restore 20% of uncontrolled impervious surfaces based on watershed assessments during each five-year permit cycle
  • Assessment of Control: document work toward meeting watershed restoration goals, including total maximum daily loads (TMDLs)*, using chemical, biological, and physical monitoring
  • Program Funding: provide an annual fiscal analysis of the capital, operation, and maintenance expenditures necessary to comply with permit conditions
More information on TMDLs may be found on MDE's webpage here: Introduction to TMDLs
 

Additional Resources

 

Guidance for Maryland's NPDES Stormwater Permits

NPDES municipal separate storm sewer system permits in Maryland require the restoration of a certain percent of a jurisdiction's impervious surface area (e.g., 20%) that has little or no stormwater management. How to calculate impervious surface requirements and treatment credits has generated numerous questions. This document standardizes procedures for reporting of traditional, new, and alternative best management practices (BMPs) and the impervious area each controls. The guidance may be found here: 
The following documents were developed to help the Department assess the physical and financial capacity of Phase I Large permittees to meet proposed restoration goals. The first documents are the instructions and spreadsheets sent to each Phase I large permittee:
Other Guidance Documents:

Since 2014, MDE has distributed several memoranda that provide additional guidance concerning BMPs and impervious area crediting.  Please note that these memoranda are intended to clarify, supplement, or replace the information found in the Accounting for Stormwater Wasteload Allocations and Impervious Acres Treated (MDE, 2014).  When there are conflicts between these memoranda and the original 2014 guidance, the newest shall supersede. These documents may be found here:
Additionally, in March 2018, MDE sent a letter to OptiRTC, Incorporated that established requirements and interim credits for the use of continuous monitoring and adaptive control (CMAC) systems for restoration.  While this letter is addressed to OptiRTC, the conditions and restrictions apply to CMAC systems in general, includiong those marketed by others.  A copy of this letter is available here:

 Contact Info

Questions about NPDES municipal permits may be directed to the Sediment, Stormwater, and Dam Safety Program at 410-537-3543 or emailed to Mr. Raymond Bahr at Raymond.Bahr@maryland.gov. ​​​