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


The Maryland Department of the Environment, Water and Science Administration (MDE\WMA) has reached a tentative determination to issue a National Pollutant Discharge Elimination System (NPDES) General Permit for Discharges from Small Municipal Separate Storm Sewer Systems (General Discharge Permit No. 13-IM-5500, General NPDES No. MDR055500). MDE has drafted a general permit designed to comply with United States Environmental Protection Agency’s (EPA) regulations and to control stormwater pollutant discharges from small municipal separate storm sewer systems. The permit is issued for five years.

Under the conditions of this permit, municipalities designated for coverage will be required to implement the following six minimum measures: public education and outreach; public participation and involvement; illicit discharge detection and elimination; construction site stormwater runoff control; post-construction stormwater management; and pollution prevention/good housekeeping. The permit also outlines new requirements for impervious area restoration for existing developed lands that have little or no stormwater management. Restoration planning strategies and implementation schedules required under the conditions of this permit term are consistent with addressing the water quality goals of the Chesapeake Bay TMDL by 2025. Implementation of these permit conditions will establish improved stormwater controls to reduce the discharge of pollutants, protect water quality, and satisfy the water quality requirements of federal regulations under the Clean Water Act. Penalties for failure to comply with the terms of this permit are provided.

Copies of the permit and fact sheet available here:

Questions concerning the General Permit may be directed to Mr. Raymond Bahr at, or by phone at 410-537-3545 or 1-800-633-6101 or to make an appointment during the hours of 8:00 AM to 5:00 PM. Copies of the document may be procured at a cost of 36¢ per page.

MDE held a public hearing concerning this tentative determination on February 6, 2017 at MDE, and accepted written comments through March 30, 2017. This comment period incorporated the additional 60 day extension period provided in Environment Article §1-606(d)(2)(ii).

Transcripts and the Attendance List from the Public Hearing, and the written comments received may be viewed here: