Industrial GP Compliance Assistance

Industrial Stormwater General Permit Compliance Assistance

Whether you’re new to the Industrial Stormwater Program or working to maintain compliance with your existing coverage, this page provides the tools and guidance you need. From understanding your Industrial Stormwater General Permit responsibilities to preventing violations, DEEP is here to support your compliance journey.

Use the links below to learn how to meet permit requirements, develop and implement a Stormwater Pollution Prevention Plan (SWPPP), understand monitoring and reporting obligations, prepare for inspections, and learn how enforcement is addressed.

If you have questions, need help interpreting permit conditions, or want to confirm you’re on the right track, visit the bottom of this page to contact DEEP for assistance.

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Overview

The Industrial Stormwater General Permit (IGP) regulates stormwater discharges associated with industrial activity. The permit requires eligible facilities to implement best management practices (BMPs), prepare and maintain a Stormwater Pollution Prevention Plan (SWPPP), monitor stormwater discharges, and submit required notifications and reports. This page provides practical compliance assistance to help you meet those obligations and protect water quality.

Who Needs Coverage?

Facilities that discharge stormwater associated with industrial activity to surface waters or to a municipal sewer system must determine whether they need coverage under the IGP. Typical industrial sectors include manufacturing, transportation, metal finishing, warehousing, chemicals, recycling, and facilities with exposed industrial materials or activities.

Tip: If your facility has exposed industrial material or activities that can be carried by runoff, you likely need coverage.

How to get Covered: Step-by-Step

Determine Eligibility - Confirm your industrial SIC/NAICS and discharge point
Develop a SWPPP - Document site conditions, pollutant sources, BMPs, monitoring points, and corrective actions.
Prepare and submit the Notice of Intent (NOI) - Includes Facility ID, receiving water, and certification of compliance.
Implement BMPs and begin monitoring - Follow permit schedules for sampling and monitoring.
Submit required reports - Monitoring results and required notifications must be submitted by permit deadlines.

SWPPP & Best Management Practices (BMPs)

SWPPP minimum elements: site map (drainage, outfalls, sampling locations), inventory of exposed materials, BMP descriptions, inspection/maintenance schedule, monitoring plan, employee training plan, corrective action plan, recordkeeping procedures.
Core BMP categories: source control, good housekeeping, structural controls, treatment controls, operational controls.
Action item: If your SWPPP is incomplete, update it now - it's a permit requirement.

Monitoring & Reporting

Monitoring begins in January 2026

Sampling Basics: Use approved methods, trained personnel, and certified labs. Sample during qualifying storm events as defined in the permit. Document weather conditions, chain-of-custody, and field observations.
Benchmark exceedances: Investigate the source, implement corrective measures, resample as required, and document in the SWPPP.
Records & retention: keep monitoring records, lab reports, and inspection logs for the retention period required by the permit.
Monitoring types:
- Benchmark monitoring - semi-annual
- Effluent limits monitoring - sector-specific
- Impaired waters monitoring - annual
- Aquatic toxicity testing - once per permit term
- Corrective action monitoring - as needed
Discharge Monitoring Reports (DMRs) are required for all permittees. Updated paper DMRs are available in the Forms and Resources section

Reporting Deadlines

DMR Reporting Timeline

Reporting Method

Before Receipt of your Notice

of Coverage

Email Paper DMRs to:

DEEP.StormwaterIndustrial@ct.gov

After Receipt of your Notice of

Coverage

Submit electronically via EPA's NetDMR

Platform

NetDMR

Monitoring Frequency	Submission Deadline
Quarterly	30 days after the monitoring period ends (i.e. April 30, July 30, October 30, January 30)
Semi-Annual	July 30 & January 30
Annual	January 30

Annual Report

The Annual Report is due April 15th after each calendar year. The first Annual Report is due in April 2027!
Annual Report Form: Coming Soon!
Submission: DEEP.StormwaterIndustrial@ct.gov

Inspections & Enforcement

DEEP and authorized municipal/federal inspectors may conduct announced or unannounced inspections. Inspectors typically review your NOI/coverage, SWPPP and BMPs, inspection logs, monitoring results, and corrective action records.

Inspections
- Routine Inspections are required daily, weekly, and monthly based on site conditions
- Comprehensive Inspections are required annually
- Quarterly Visual assessments are required of discharged samples

Corrective Action Measures: The Permit has built in steps facilities must take
Enforcement actions may include notices of violation, consent/administrative orders, and monetary penalties. DEEP prioritizes assistance and compliance first.

Forms & Resources

SWPPP Template & Checklist
BMP Fact Sheets: Coming Soon!
Stormwater Sampling Guidance: Coming Soon!
Sector Specific Discharge Monitoring Reports
- Sector A - Timber Products
- Sector B - Paper and Allied Products Manufacturing
- Sector C - Chemical and Allied Products Manufacturing and Refining
- Sector D - Asphalt Paving and Roofing Materials and Lubricant Manufacturing
- Sector E - Glass, Clay, Cement, Concrete, and Gypsum Products
- Sector F - Primary Metals
- Sector G – Reserved for Future Use
- Sector H – Reserved for Future Use
- Sector I – Reserved for Future Use
- Sector J – Non-metallic Mineral Mining and Dressing
- Sector K - Hazardous Waste Treatment, Storage, or Disposal Facilities
- Sector L – Landfills, Land Application Sites, and Open Dumps
- Sector M – Automobile Salvage Yards
- Sector N – Scrap Recycling and Waste Recycling Facilities
- Sector O – Steam Electric Power Generation (SIC Code 4911)
- Sector P – Land Transportation and Warehousing
- Sector Q – Water Transportation (Marinas, Yacht Clubs, and Boat Dealers)
- Sector R – Ship and Boat Building and Repair Yards
- Sector S – Air Transportation
- Sector T – Treatment Works
- Sector U – Food and Kindred Products
- Sector V – Textile Mills, Apparel, and Other Fabric Products
- Sector W – Furniture and Fixtures
- Sector X – Printing and Publishing
- Sector Y – Rubber, Miscellaneous Plastic Products and Miscellaneous Manufacturing Industries
- Sector Z –Reserved for Future Use
- Sector AA – Fabricated Metal Products
- Sector AB – Transportation Equipment, Industrial or Commercial Machinery Facilities
- Sector AC – Electronic and Electrical Equipment and components. Photographic and Optical Goods
- Sector AD – Reserved for Future Use
- Sector AE – Bulk Solid De-icing Material Storage
- Sector AF – Federal, State, or Municipal Fleet Facilities
- Sector AG – Small-Scale Composting Facilities
- Sector AH – Stormwater Discharges Designated by the Commissioner as Requiring Permits

Resources and Contact Information

Compliance Assistance

Environmental Protection Agency

Contact Information

For questions regarding the Industrial Stormwater Permit, contact: DEEP.StormwaterIndustrial@ct.gov
For general stormwater questions, contact: DEEP.Stormwaterstaff@ct.gov
Environmental or DEEP related emergencies

Last updated November 24, 2025

Connecticut Department of Energy & Environmental Protection