General Discharge Permit

General Permit For Discharges of Stormwater Associated With Industrial Activity
Maryland General Permit No. 12-SW 

 ​Important Announcement - Training Opportunity 

The Maryland Center for Environmental Training (MCET), in partnership with MDE, will provide a special training for business owners, operators, and consultants regarding the 12-SW General Permit.  Attendees may choose a one or two day session at MDE's headquarters in Baltimore City on November 27-28, 2018.  Please see this brochure​ and/or contact MCET at 301-934-7500 with questions.

Important Announcement (updated October 11, 2018)

The existing General Permit 12-SW has an expiration date of December 31, 2018.  The Department has not proposed a new permit and the existing permit and all registrations under it will auto-extend until a new version is issued.  Please check back here for updates as progress is made towards that end.  Once a draft of the new permit has been proposed, the Department will take comments prior to issuance.  

The Department proposed a modification to the existing permit (General Permit 12-SW-A).  The comment period for this modification closed on September 19, 2018 and a final determination is currently being completed.  However, the Department anticipates that its final determination will not include any extension of the existing required completion deadline for Chesapeake Bay restoration.  The close of business on December 31, 2018 will remain the required date that restoration practices need to begin achieiving reductions in total nitrogen.  Other comments regarding the proposed modification are still being evaluated, and the Department intends to finalize the modification as soon as possible, but by no later than the end of ​the year.  A notice will be sent to registrants and interested parties and this webpage will be updated accordingly once the modification is finalized.  

Existing Permit (before pending modification)


Guidance Documents

Supplemental Information

Contact Info

For more information on this permit, contact the Industrial and General Permits Division at (410) 537-3323.

Additional Information and Related Links