Stormwater Management Concept 

WHY IS A STORMWATER MANAGEMENT (SM) CONCEPT REVIEW NECESSARY?

A stormwater management concept is a statement or drawing, or both, describing the manner in which stormwater runoff from a proposed development will be controlled to minimize damage to neighboring properties and receiving streams and to also prevent the discharge of pollutants into surface waters. 

WHEN DO I NEED A SM CONCEPT APPROVAL?

A Stormwater Management Concept approval is required prior to preliminary subdivision plan approval by the M-NCPPC, and for most other development activity prior to the application for a Sediment Control Permit.

ARE ANY DEVELOPMENT ACTIVITIES EXEMPT FROM CONCEPT APPROVAL?

• The following development activities are not subject to DPS stormwater management requirements and are therefore exempt from the SM Concept requirement.
  • Agricultural activities.
  • Additions or modifications to existing residential structures with less than 5,000 sq. ft. of land disturbance.
  • Land-development activities regulated at the State level.
  • Activities that disturb ground solely for the purpose of maintenance, such as parking lot repair or mill and overlay projects.

Please note that a separate stormwater management concept is NOT required for construction on existing single family lots where the use is single family residential.  In such cases, stormwater management must be shown on the sediment control plan at the time of detailed plan submission.  If the property is going through the subdivision process, or if the proposed use is something other than single family residential, a separate stormwater management concept is required.

WHAT ARE THE REQUIREMENTS OF THE STORMWATER MANAGEMENT CONCEPTS?

The goal of stormwater management is to mitigate the effects of development on the receiving stream system. Stormwater management concepts must show how acceptable mitigation is achieved by implementing practices in accordance with the 2000 Maryland Department of the Environment's Stormwater Design Manual as amended and withMontgomeryCountydesign requirements based on Chapter 19 of the Montgomery County Code.

DPS Water Resources staff will review the stormwater management concept to ensure conformance with these requirements and with applicable Executive Regulation.

All projects must use Environmentally Sensitive Design (ESD) credits to the maximum extent practicable (MEP) to provide the full stormwater management requirement calculated for the project.  ESD requirements shall be calculated per MontgomeryCounty Water Resources Technical Policy WRTP-5.

In extreme cases the applicant may request a waiver of providing on-site stormwater management. When granted by the Department of Permitting Services an appropriate stormwater management contribution will be required in accordance with Executive Regulation 4-90AM.

WHAT IS THE STORMWATER MANAGEMENT APPLICATION PROCESS?

Submit a completed SM Concept Application, a copy of the grading or site plan (along with applicable supporting information), and the appropriate application fee. Please refer to the second page of the SM Concept Application for submittal requirements.

CONDITIONS OF APPROVAL

A SM Concept is approved when an approval letter has been issued by the Department of Permitting Services.

OTHER AGENCIES INVOLVED

In accordance with Chapter 19 of the Montgomery County Code, DPS must route all new stormwater concept application packages to the Montgomery County Department of Transportation, the Montgomery County Department of Environmental Protection, and the MNCPPC prior to taking action on the application.  DPS allows these agencies three weeks in which to submit comment.  During this period, no action will be taken on the stormwater concept review package by DPS.  This mandatory agency comment period applies only to the initial stormwater concept submission, and does not apply to subsequent submissions and revisions.

WHAT WILL THE SM CONCEPT APPLICATION COST?

1. For stormwater management concept plans which are 25 acres or less in total property area - $2,684.00

2. All other stormwater management concept plans which are greater than 25 acres  in total property area - $3,432.00

3. Fees for revisions to previously approved stormwater management concept plans are 50% of the current fee.

The above fees include a 10% automation enhancement fee. Filing fees and permit fees are based on fees in effect on the date the application was filed. All other fees are based on fees in effect at the time the service is requested (revision fee, extension fee, etc.).

WHEN WILL I RECEIVE MY SM CONCEPT APPROVAL?

• A Stormwater Management Concept typically takes approximately three to six weeks for approval following the mandatory three week agency comment period.

The approval is valid for the life of the associated preliminary plan approved by MNCPPC or the term of the applicable law and Executive Regulation at the time of approval. Actual processing time may vary according to workload and/or complexity of the project.  Any divergence from the information provided to this office; or additional information received during the development process; or a change in an applicable Executive Regulation may constitute grounds to rescind or amend any approval actions taken, and to reevaluate the site for additional or amended stormwater management requirements.  If there are subsequent additions or modifications to the development, a separate concept request shall be required.