Municipal Separate Stormwater Sewer Systems (MS4s)

Contacts
Statutory sections
Rules
Forms
General permit
MS4 Documents
Supplemental materials

The MS4 general permits describe permit coverage and limitations, definitions, authorization and notice requirements, stormwater program management plan requirements, and standard conditions for municipalities, transportation MS4s and state federally-owned MS4s.

Contact

• Holliday Keen (207) 242-4649

Statutory sections

• Waste discharge laws. 38 MRSA § § 413, et. seq. (off-site).
• Water classification laws. See the Classification page.

Rules

• General Permits for Certain Wastewater Discharges, Ch. 529, (off-site).
• See also the Waste Discharge Program Page.
• Note: links are to on-line rules maintained by Maine's Secretary of State's Office. Files are in msword and sometimes take a little while to load.

Forms

• Notice of Intent (NOI) to comply with Maine General Permit (PDF)
• Illicit Discharge Detection and Elimination Manual -- A Handbook for Municipalities. January, 2003. New England Interstate Water Pollution Control Commission. (off-site)

General permits

The three MS4 general permits are effective July 1, 2013.

1. Small Municipal. General Permit for the Discharge of Stormwater From Small Municipal Separate Storm Sewer Systems
2. Transportation. General Permit for the Discharge of Stormwater From Maine Department of Transportation and Maine Turnpike Authority Municipal Separate Storm Sewer System Facilities
3. State or federal. General Permit for the Discharge of Stormwater From State or Federally Owned Municipal Separate Storm Sewer System Facilities

The following MS4 general permit becomes effective July 1, 2022.

1. General Permit for the Discharge of Stormwater from Municipal Small Municipal Separate Storm Sewer Systems (MS4) MER041000

   a. Municipal MS4 Final Permit Modification
   b. Municipal Final Second Step Permits
   c. Municipal Final Modified Stormwater Management Plans (SWMPs)

2. General Permit for the Discharge of Stormwater from Maine Department of Transportation and Maine Turnpike Authority Municipal Separate Storm Sewer Systems MER043000

   a. Transportation MS4 Final Second Step Permits
   b. Transportation Final Modified Stormwater Management Plans

3. General Permit for the Discharge of Stormwater from Small State and Federally Owned Municipal Separate Storm Sewer Systems (MER42000) effective October 1, 2022

a. State and Federal MS4 Final Second Step Permits
b. State and Federal Final Modified Stormwater Management Plans

MS4 Documents

• NPDES Phase II Stormwater Program -- Regulated MS4 Permittees Notices of Intent (NOI), Stormwater Management Plans, and Maps
• Municipal Separate Stormwater Sewer Systems Regulated Areas (5/27/2014)      

Supplemental materials

• 2013 MS4 General Permit Fact Sheet
• Urban impaired stream watershed map in Google Earth

To obtain hard copies of the materials listed above, call your nearest DEP regional office, or email.