Maryland Stormwater-Municipalities regulations & environmental compliance analysis

Maryland Stormwater-Municipalities: What you need to know

Governing Law and Regulations

General stormwater permits: Code of Maryland Regulations (COMAR) and COMAR

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Municipalities: COMAR

Regulatory Agencies

Maryland Department of the Environment (MDE)Water Management Administration

U.S. Environmental Protection Agency (EPA)Region 3

See ADDRESSES & CONTACTS for addresses and telephone numbers.

See national section for basic information and federal regulations.

Comparison: State vs. Federal

Rules. Maryland is authorized by the U.S. Environmental Protection Agency (EPA) to administer the federal National Pollutant Discharge Elimination System (NPDES) permit program for wastewater discharges, including stormwater discharges associated with municipal separate storm sewer systems (MS4s). The state generally follows the federal MS4 permitting requirements. See the national section STORMWATER—MUNICIPALITIES for more information.

Administration and enforcement. MDE's Water Management Administration is responsible for enforcing and administering the NPDES stormwater discharge permit program for MS4s in Maryland.

State Requirements



The municipal stormwater permit is required for owners of MS4s serving large, medium, and small municipalities. A large municipality is one that serves a population of 250,000 or more. A medium municipality is one that serves a population between 100,000 and 250,000. The following jurisdictions in Maryland are large municipalities: Anne Arundel, Baltimore, Montgomery, and Prince George's counties and Baltimore City. Carroll, Charles, Frederick, Harford, and Howard counties are considered medium municipalities.

The MDE has issued two general permits to cover small ...

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