Clean Water Act discharge permit · NPDES WI0020478
SUN PRAIRIE WASTEWATER TREATMENT FACILITY, Sun Prairie, WI: NPDES WI0020478 discharge permit, effluent exceedances, inspections, penalties
- Administratively continuedPermit status
- MajorDischarger class
- 10Pollutants under a numeric limit
- 7Pollutants with an effluent exceedance
SUN PRAIRIE WASTEWATER TREATMENT FACILITY, held by CITY OF SUN PRAIRIE, holds NPDES permit WI0020478, which discharges to Koshkonong Cr. EPA’s file records it issued November 7, 2013 and expiring September 30, 2018. 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 | SUN PRAIRIE WASTEWATER TREATMENT FACILITY |
|---|---|
| Permittee as filed | CITY OF SUN PRAIRIE |
| NPDES ID | WI0020478 |
| Permit status | Administratively continued (past its expiration date and still in force until reissued) |
| Permit type | Individual permit |
| Discharger class | Major discharger |
| Facility type | Publicly owned treatment works |
| Program | Publicly owned treatment works |
| Issued | November 7, 2013 |
| Expiration date | September 30, 2018 |
| Address | Sun Prairie, WI 53590 |
| Receiving water | KOSHKONONG CR |
| Receiving water impaired | 303(D) Listed |
| Subwatershed | Headwaters Koshkonong Creek (HUC 070900020401) |
Cited to the EPA ICIS-NPDES permit file (ECHO download).
Effluent limits and exceedances
- 14Pollutants on file
- 10Under a numeric limit
- 12With a violation of any kind
- 7With 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 |
|---|---|---|---|---|---|
| Oxygen, dissolved [DO] | 1 | 18 | 18 | January 31, 2007 | 14% over the limit |
| Nitrogen, ammonia total [as N] | 9 | 10 | 10 | January 31, 2016 | 174% over the limit |
| BOD, 5-day, 20 deg. C | 8 | 6 | 6 | June 30, 2023 | 96% over the limit |
| Chlorine, total residual | 0 | 4 | 4 | August 31, 2004 | 724% over the limit |
| Solids, total suspended | 32 | 3 | 3 | September 30, 2018 | 28% over the limit |
| Phosphorus, total [as P] | 4 | 46 | 1 | January 31, 2007 | 3% over the limit |
| Chloride [as Cl] | 5 | 1 | 1 | February 28, 2005 | 4% over the limit |
| Coliform, fecal general | 1 | 47 | 0 | ||
| Mercury, total recoverable | 2 | 18 | 0 | ||
| Nitrogen, total [as N] | 0 | 9 | 0 | ||
| Nitrogen, Kjeldahl, total [as N] | 0 | 9 | 0 | ||
| Nitrite + Nitrate total [as N] | 0 | 9 | 0 | ||
| Flow, in conduit or thru treatment plant | 4 | 0 | 0 | ||
| pH | 2 | 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
- 1Single-event violations
| Date | What EPA recorded | Agency |
|---|---|---|
| June 23, 2024 | WW SSO - Discharge to Waters | ST6 |
Velarion’s copy of EPA’s ICIS-NPDES files does not yet 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
One permit holder, $99/month. Watch the register for one permit holder and the places and receiving waters tied to its permits. Choose “One permit holder” and enter this permit’s NPDES ID, WI0020478.
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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 WI0020478 there.
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Figures from EPA’s ICIS-NPDES download, loaded September 14, 2026.