Clean Water Act discharge permit · NPDES PA0009920
THREE MILE ISLAND NUCLEAR STATION, Londonderry, Township Of, PA: NPDES PA0009920 discharge permit, effluent exceedances, inspections, penalties
- Administratively continuedPermit status
- MajorDischarger class
- 0Pollutants under a numeric limit
- 4Pollutants with an effluent exceedance
THREE MILE ISLAND NUCLEAR STATION, held by AMERGEN ENERGY CO LLC - THREE, holds NPDES permit PA0009920, which discharges to Susquehanna River In Watershed 7-G. EPA’s file records it issued September 30, 2002 and expiring October 1, 2007. The status and dates are as EPA’s permit file stood when Velarion loaded it (September 14, 2026); EPA’s free Detailed Facility Report on ECHO carries the permit’s current standing.
Identity
| Facility as filed | THREE MILE ISLAND NUCLEAR STATION |
|---|---|
| Permittee as filed | AMERGEN ENERGY CO LLC - THREE |
| NPDES ID | PA0009920 |
| 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 | September 30, 2002 |
| Expiration date | October 1, 2007 |
| Address | Londonderry, Township Of, PA 17057 |
| Receiving water | SUSQUEHANNA RIVER IN WATERSHED 7-G |
| Receiving water impaired | 303(D) Listed |
| Subwatershed | Laurel Run-Susquehanna River (HUC 020503051011) |
Cited to the EPA ICIS-NPDES permit file (ECHO download).
Effluent limits and exceedances
- 12Pollutants on file
- 0Under a numeric limit
- 12With a violation of any kind
- 4With 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 |
|---|---|---|---|---|---|
| Solids, total suspended | 0 | 17 | 2 | October 31, 2003 | 303% over the limit |
| Hydrazine | 0 | 5 | 2 | April 30, 2018 | 99,999% over the limit |
| pH | 0 | 15 | 1 | November 30, 1999 | |
| Chlorine, free available | 0 | 4 | 1 | August 31, 2017 | 150% over the limit |
| Flow, in conduit or thru treatment plant | 0 | 16 | 0 | ||
| Oil & Grease | 0 | 8 | 0 | ||
| Temperature, water deg. fahrenheit | 0 | 3 | 0 | ||
| Oxidants, total residual | 0 | 3 | 0 | ||
| Spectrus CT 1300 | 0 | 3 | 0 | ||
| Phosphorus, total [as P] | 0 | 1 | 0 | ||
| Coliform, fecal general | 0 | 1 | 0 | ||
| BOD, carbonaceous [5 day, 20 C] | 0 | 1 | 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
- 2Single-event violations
| Date | What EPA recorded | Agency |
|---|---|---|
| January 21, 2026 | Permit Violations - Failure to Pay Fees | ST6 |
| January 8, 2025 | Permit Violations - Failure to Pay Fees | 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.
Watch this permit
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EPA publishes a free Detailed Facility Report for every permit on ECHO: its compliance status quarter by quarter, its inspections, and its enforcement actions and penalties. EPA also sends free notices of new inspections and enforcement actions through ECHO Notify; enter NPDES ID PA0009920 there.
Nearby on the register
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Figures from EPA’s ICIS-NPDES download, loaded September 14, 2026.