Clean Water Act discharge permit · NPDES CT0003824
ELECTRIC BOAT CORPORATION, Groton, CT: NPDES CT0003824 discharge permit, effluent exceedances, inspections, penalties
- Administratively continuedPermit status
- MajorDischarger class
- 36Pollutants under a numeric limit
- 15Pollutants with an effluent exceedance
ELECTRIC BOAT CORPORATION holds NPDES permit CT0003824, which discharges to Thames River. EPA’s file records it issued July 1, 2006 and expiring June 30, 2011. The status and dates are as EPA’s permit file stood when Velarion loaded it (September 15, 2026); EPA’s free Detailed Facility Report on ECHO carries the permit’s current standing.
Identity
| Facility as filed | ELECTRIC BOAT CORPORATION |
|---|---|
| Permittee as filed | ELECTRIC BOAT CORPORATION |
| NPDES ID | CT0003824 |
| Permit status | Administratively continued (past its expiration date and still in force until reissued) |
| Permit type | Individual permit |
| Discharger class | Major discharger |
| Facility type | Not a publicly owned treatment works |
| Issued | July 1, 2006 |
| Expiration date | June 30, 2011 |
| Issuing agency | CT DEP |
| Address | Groton, CT 06340 |
| Receiving water | THAMES RIVER |
| Receiving water impaired | 303(D) Listed |
| Subwatershed | Thames River-Frontal New London Harbor (HUC 011000030203) |
| Other EPA IDs (FRS) | RCRA handler CTD001147842; ICIS-AIR source CT0000000901100039 |
Cited to the EPA ICIS-NPDES permit file (ECHO download); cross-program IDs from EPA’s FRS facility-registry crosswalk.
Effluent limits and exceedances
- 44Pollutants on file
- 36Under a numeric limit
- 29With a violation of any kind
- 15With an effluent exceedance
An effluent exceedance is a discharge monitoring report value over the permit’s numeric limit (EPA’s violation code E90). A violation of any kind also counts a report not filed. Each row is EPA’s own count for that pollutant.
| Pollutant or measure | Limits | Violations, any kind | Effluent exceedances | Latest exceedance | Largest exceedance, as filed |
|---|---|---|---|---|---|
| Copper, total [as Cu] | 29 | 82 | 39 | January 31, 2025 | 2,229% over the limit |
| pH | 28 | 173 | 29 | April 30, 2025 | |
| Flow, maximum during 24 hr period | 15 | 28 | 24 | June 30, 2026 | 218% over the limit |
| Flow rate | 7 | 13 | 11 | September 30, 2009 | 3,854% over the limit |
| Chlorine, free available | 1 | 9 | 9 | May 31, 2005 | 225% over the limit |
| Oil & Grease | 13 | 41 | 6 | June 30, 2025 | 140% over the limit |
| Oxidants, free available | 12 | 6 | 6 | September 30, 2022 | 640% over the limit |
| Solids, total suspended | 13 | 39 | 4 | February 29, 2008 | 227% over the limit |
| Flow rate | 9 | 6 | 4 | July 31, 2010 | 46% over the limit |
| %Effect Static Renewal 96Hr Acute Cyprinodon variegatus | 3 | 4 | 3 | March 31, 2008 | 64% over the limit |
| NOAEL Static 48Hr Acute Cyprinodon variegatus | 19 | 3 | 2 | January 31, 2010 | 100% over the limit |
| Noael Static 48Hr Acute Mysid. Bahia | 3 | 3 | 2 | October 31, 2007 | 4% over the limit |
| Flow | 0 | 5 | 1 | August 31, 1998 | 692% over the limit |
| %Surv Static 96Hr Acute Mysidopsis Bahia | 19 | 2 | 1 | January 31, 2010 | 96% over the limit |
| pH, maximum | 0 | 1 | 1 | July 31, 2025 | |
| Zinc, total [as Zn] | 21 | 37 | 0 | ||
| Iron, total [as Fe] | 3 | 35 | 0 | ||
| Chlorine, total residual | 2 | 35 | 0 | ||
| Pass/Fail Static 4 Day Chronic Mysidopsis Bahia | 0 | 16 | 0 | ||
| Lead, total [as Pb] | 16 | 4 | 0 | ||
| Oxidants, total residual | 11 | 3 | 0 | ||
| LC50 Static 48Hr Acute Americamysis bahia (formerly Mysidopsis bahia) | 4 | 2 | 0 | ||
| LC50 Static 48Hr Acute Cyprinodon variegatus | 4 | 2 | 0 | ||
| Selenium, total [as Se] | 0 | 2 | 0 | ||
| Temperature, water deg. fahrenheit | 4 | 1 | 0 | ||
| NOEC Lethal Static Renewal 7 Day Chronic Americamysis bahia (formerly Mysidopsis bahia) | 0 | 1 | 0 | ||
| NOEC Lethal Static Renewal 7 Day Chronic Cyprinodeon variegatus | 0 | 1 | 0 | ||
| NOEC Sub-Lethal Static Renewal 7 Day Chronic Americamysis bahia (formerly Mysidopsis bahia) | 0 | 1 | 0 | ||
| NOEC Sub-Lethal Static Renewal 7 Day Chronic Cyprinodeon variegatus | 0 | 1 | 0 | ||
| Chromium, total [as Cr] | 9 | 0 | 0 | ||
| BOD, 5-day, 20 deg. C | 4 | 0 | 0 | ||
| Nickel, total [as Ni] | 4 | 0 | 0 | ||
| Nitrogen, total [as N] | 2 | 0 | 0 | ||
| Nitrogen, nitrate total [as N] | 2 | 0 | 0 | ||
| Phosphorus, total [as P] | 2 | 0 | 0 | ||
| Arsenic, total [as As] | 2 | 0 | 0 | ||
| Cadmium, total [as Cd] | 2 | 0 | 0 | ||
| Strontium, total [as Sr] | 2 | 0 | 0 | ||
| Aluminum, total [as Al] | 2 | 0 | 0 | ||
| Titanium, total [as Ti] | 2 | 0 | 0 | ||
| Chlorine produced oxidants | 1 | 0 | 0 | ||
| Ethylbenzene | 1 | 0 | 0 | ||
| Mercury, total [as Hg] | 1 | 0 | 0 | ||
| Xylene [mix of m+o+p] | 1 | 0 | 0 |
Cited to the EPA ICIS-NPDES limits and effluent violations files (ECHO download); up to 60 rows shown, most exceedances first.
Inspections, violations and enforcement
- 10Single-event violations
| Date | What EPA recorded | Agency |
|---|---|---|
| April 28, 2026 | Monitoring Violations - Failure to Monitor for Non-Toxicity Requirements | ST6 |
| April 28, 2026 | Reporting Violations - Failure to submit required report (non-DMR non-pretreatment) | ST6 |
| April 28, 2026 | Management Practice Violations - Best Management Practice Deficiencies | ST6 |
| April 28, 2026 | Permit Violations - Violation Specified in Comment | ST6 |
| June 5, 2025 | Management Practice Violations - Failure to Maintain Records | ST6 |
| June 5, 2025 | Permit Violations - Discharge Without a Valid Permit | ST6 |
| June 5, 2025 | Permit Violations - Violation Specified in Comment | ST6 |
| June 5, 2025 | Permit Violations - Unapproved Operation | ST6 |
| March 21, 2023 | Permit Violations - Discharge Without a Valid Permit | ST6 |
| March 21, 2023 | Management Practice Violations - Improper Operation and Maintenance | ST6 |
Velarion’s copy of EPA’s ICIS-NPDES files does not include the inspections, formal enforcement actions and informal enforcement actions files, so this page shows none of them. EPA’s free Detailed Facility Report on ECHO lists this permit’s inspections, enforcement actions and penalties.
Cited to the EPA ICIS-NPDES violation, inspection and enforcement files (ECHO download); up to 50 rows of each shown, newest first.
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Figures from EPA’s ICIS-NPDES download, loaded September 15, 2026.