Stormwater Permit

Municipalities, transportation agencies, public universities, prisons, military bases, and other state and federal facilities are subject to Maine Pollution Discharge Elimination System (MEPDES) regulation. This includes the Municipal Separate Storm Sewer System (MS4) permit. Regulated MS4 municipalities are determined by using US Census Bureau population density and proximity to population density data gathered during the decennial census.

MS4 municipalities must fully comply with permit requirements, including six Minimum Control Measures (MCMs) outlined in the permit:

1. Educate the public and smaller focus groups about polluted runoff and how to reduce pollution.

2. Provide the public opportunities to participate in the municipality’s stormwater program through meetings, public comment periods, and events.

3. Identify and eliminate illegal sewer connections, dumping into storm drains, and other sources of pollution. Carry out long-term maintenance and mapping of all stormwater infrastructure.

4. Ensure that construction on both public and private property does not impact water resources.

5. Implement new development and redevelopment stormwater ordinances, and encourage developers to utilize techniques to reduce the impact of development on water resources.

6. Prevent pollution from municipal operations and facilities. Educate municipal staff about practices to reduce polluted runoff.

Municipalities regulated under the MEPDES program are subject to compliance audits from both the Maine Department of Environmental Protection (DEP) and the US Environmental Protection Agency (EPA). Audits can occur at any time and with little warning, but municipalities can take steps now to ensure their documentation is complete and provide sufficient evidence of permit compliance.