General Permit for the Discharge of Stormwater from Small Municipal Separate Storm Sewer Systems -3/21/25
Notice of Tentative Determination to Reissue the General Permit for the Discharge of Stormwater from Small Municipal Separate Storm Sewer Systems
1.0 Tentative Determination
The Commissioner of the Department of Energy and Environmental Protection (“DEEP”) hereby gives notice of a tentative determination to reissue and administer the General Permit for the Discharge of Stormwater from Small Municipal Separate Storm Sewer Systems (“Small MS4 General Permit” or “general permit”) under the authority of sections 22a-430 and 22a-430b of the Connecticut General Statutes (“CGS”) authorizing point source discharges to surface water.
2.0 Commissioner’s Findings
The purpose of the general permit is to protect the waters of the state from stormwater runoff discharging from municipal separate storm sewer systems (“MS4s”) owned by municipalities and state and federal institutions of a certain size. The current Small MS4 General Permit became effective on September 30, 2023, with a permit duration of two (2) years and an expiration date of September 30, 2025.
In accordance with applicable federal and state law, the Commissioner has made a tentative determination that discharges in accordance with, and authorized under, the Small MS4 general permit would not cause pollution to the waters of the state. The proposed general permit, if issued as drafted, will require
registration for new and existing permittees and the development and implementation of a Stormwater Management Plan (“SMP”).
3.0 General Permit Regulatory Conditions
The general permit authorizes the discharge of stormwater from MS4s to surface waters of the state of Connecticut. Any discharge of water, substance or material into the waters of the state other than the ones specified in the general permit are not authorized by this general permit.
The general permit requires eligible facilities to submit a registration to obtain permit coverage, develop
and implement a SMP, conduct stormwater outfall monitoring to identify discharges contributing to stream impairments, and the submission of Annual Reports to track the progress of implementation of the SMP. In addition to the impaired waters monitoring program, the SMP must include detailed information regarding
the implementation of the six (6) minimum control measures: (1) Public Education and Outreach, (2) Public Involvement and Participation, (3) Illicit Discharge Detection and Elimination, (4) Construction Site Stormwater Runoff Control, (5) Post-construction Stormwater Management, and (6) Pollution Prevention
and Good Housekeeping.
4.0 Proposed Updates
Significant changes proposed for the general permit include the following: an expansion of the definition of Small MS4 to include municipalities with greater than 1,000 residents within an area designated by the United States Census Bureau as an Urban Area (formerly Urbanized Area) and requiring permit coverage
for seven (7) new towns (Colchester, East Hampton, Harwinton, Stafford, Torrington, Winchester, and Windham); the simplification of the Illicit Discharge Detection and Elimination (“IDDE”) protocol, including the elimination of wet weather screening and seasonal sampling restrictions, and improved step-by-step guidance; the inclusion of a new crediting scheme for the use of stormwater treatment to contribute to the goals of the Directly Connected Impervious Area (“DCIA”) reduction program (formerly the DCIA disconnection program) along with a new Appendix for guidance on implementation; and, a new monitoring scheme for the impaired waters monitoring program to clarify requirements, provide a more focused approach for permittees and improve the quality of stormwater data provided to DEEP.
To comply with the NPDES Electronic Reporting Rule (40 CFR 127), registration and reporting requirements under the general permit will transition to electronic filing. Applicants will follow a two-step process: (1) Submit an application transmittal form and (2) upload an electronic application to a shared online portal. Permittees will then submit their annual reports electronically through EPA’s NetDMR platform.
5.0 Commissioner’s Authority
The Commissioner is authorized to issue this general permit pursuant to sections 22a-430 and 22a-430b of the CGS and the Water Discharge Permit Regulations (sections 22a-430-3 and 4 of the Regulations of Connecticut State Agencies). The Commissioner is authorized to approve or deny any registration under
this general permit pursuant to CGS section 22a-430b.
6.0 Public Comment
Interested persons may obtain a copy of this public notice, the draft Small MS4 General Permit and the general permit fact sheet on the DEEP website at www.ct.gov/deep/publicnotices. The general permit materials are also available for inspection at the DEEP Bureau of Materials Management and Compliance Assurance, Water Permitting and Enforcement Division, 79 Elm Street, Hartford, CT from 8:30am – 4:30pm, Monday through Friday. Questions may be directed to Christopher Stone at 860-424-3850 or chris.stone@ct.gov
Prior to making a final decision to reissue the proposed general permit, the Commissioner shall consider written comments from interested persons that are received within thirty (30) days of this public notice. Written comments should be directed to: Christopher Stone, Water Permitting and Enforcement Division, Bureau of Materials Management and Compliance Assurance, Department of Energy and Environmental Protection, 79 Elm Street, Hartford, CT 061065127 or may be submitted via electronic mail to DEEP.StormwaterStaff@ct.gov. Electronic mail is recommended.
6.0 Petitions for Public Hearing
The Commissioner may conduct a public hearing if the Commissioner determines that the public interest will be best served thereby or shall hold a hearing upon receipt of a petition signed by at least twenty-five persons. Petitions should include the name of the general permit noted above and also identify a contact person to receive notifications. Petitions may also identify a person who is authorized to engage in discussions regarding the proposed general permit and, if resolution is reached, withdraw the petition. Original signed petitions may be scanned and sent electronically to deep.adjudications@ct.gov or may
be mailed or delivered to: DEEP Office of Adjudications, 79 Elm Street, 3rd floor, Hartford, CT 06106-5127. All petitions must be received within the comment period noted above. If submitted electronically, original signed petitions must also be mailed or delivered to the address above within ten days of electronic submittal. If a hearing is held, timely notice of such hearing will be published in a newspaper of general circulation.
/s/Emma Cimino
Deputy Commissioner
Published in the Hartford Courant, New Haven Register, Connecticut Post, New London Day, Waterbury Republican-American and The Chronicle on March 21, 2025.
Draft General Permit
Fact Sheet
The Connecticut Department of Energy and Environmental Protection is an Affirmative Action and Equal Opportunity Employer that is committed to complying with the Americans with Disabilities Act. To request an accommodation contact us at 860-418-5910 or deep.accommodations@ct.gov.
Draft Small MS4 General Permit and Fact Sheet: www.ct.gov/deep/stormwater