Storm Water Management Engineering Regulations

Runoff from impervious surfaces affects local streams by increasing erosion along stream banks, silting in stream beds and depositing trash in waterways. The cumulative effect is a reduction in water quality, aquatic resources and the health of streams and the Chesapeake Bay. To improve the effects of storm water runoff, and thereby improve the quality of the Chesapeake Bay, the Maryland legislature passed the Storm Water Management (SWM) Act of 2007.

Baltimore County has prepared and received approval from the Maryland Department of the Environment (MDE) for its draft local ordinance. This will be processed through the County Council to become law.  The County's ordinance is available in PDF format for download from this web page.

This Act will significantly affect the design of storm water components for land development projects. Some of the more significant changes are:

• Environmental Site Design to the Maximum Extent Practicable must be addressed for all projects, including redevelopment.
• Three sequential plan submissions and reviews are now required: Concept SWM Plan; Development SWM Plan; and Final SWM Plan.
• Redevelopment projects will require 50 percent reduction in impervious surface or equivalent water quality management.  Currently the requirement is 20 percent.
• No grading or building permits may be issued until sediment control and SWM plans are signed.

To review the COMAR revisions and become familiar with all the changes to the Design Manual, please visit the The Maryland Department of the Environment's web site.

Baltimore County is in the process of revising its Code to incorporate State-mandated changes and has received approval from MDE of its proposed ordinance . Pursuant to COMAR, required changes must be codified by Baltimore County and become effective by May 4, 2010.  In order for a project to be grandfathered under current regulations, it must have fully approved sediment control and SWM plans by May 4, 2010. 

The current stormwater regulations  2003 SWM Regulations select this link and choose Article 33 Title 4 or you can download a copy in PDF format.

Contact Information
Storm Water Engineering
Phone: 410-887-3768
Fax:410-887-4804
E-mail: deprm@baltimorecountymd.gov

Revised March 9, 2010