Clean Water Act discharge permit · NPDES WI0021181
OCONOMOWOC WASTEWATER TREATMENT PLNT, Oconomowoc, WI: NPDES WI0021181 discharge permit, effluent exceedances, inspections, penalties
- Administratively continuedPermit status
- MajorDischarger class
- 11Pollutants under a numeric limit
- 6Pollutants with an effluent exceedance
OCONOMOWOC WASTEWATER TREATMENT PLNT, held by OCONOMOWOC WASTEWATER TREATMENT PLANT, holds NPDES permit WI0021181, which discharges to Oconomowoc R. EPA’s file records it issued April 1, 2014 and expiring March 31, 2019. 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 | OCONOMOWOC WASTEWATER TREATMENT PLNT |
|---|---|
| Permittee as filed | OCONOMOWOC WASTEWATER TREATMENT PLANT |
| NPDES ID | WI0021181 |
| 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 | April 1, 2014 |
| Expiration date | March 31, 2019 |
| Address | Oconomowoc, WI 53066 |
| Receiving water | OCONOMOWOC R |
| Subwatershed | Oconomowoc River (HUC 070900010504) |
Cited to the EPA ICIS-NPDES permit file (ECHO download).
Effluent limits and exceedances
- 12Pollutants on file
- 11Under a numeric limit
- 7With a violation of any kind
- 6With 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 |
|---|---|---|---|---|---|
| Chloride [as Cl] | 10 | 27 | 27 | May 31, 2018 | 10% over the limit |
| Chlorine, total residual | 0 | 11 | 11 | July 31, 2010 | 1,270% over the limit |
| Solids, total suspended | 47 | 7 | 7 | February 28, 2018 | 81% over the limit |
| BOD, 5-day, 20 deg. C | 12 | 7 | 7 | January 31, 2026 | 60% over the limit |
| Phosphorus, total [as P] | 4 | 2 | 2 | May 31, 2009 | 6% over the limit |
| Oxygen, dissolved [DO] | 1 | 2 | 2 | October 31, 2003 | 15% over the limit |
| Mercury, total recoverable | 2 | 22 | 0 | ||
| pH | 2 | 0 | 0 | ||
| Nitrogen, ammonia total [as N] | 2 | 0 | 0 | ||
| Flow, in conduit or thru treatment plant | 2 | 0 | 0 | ||
| Temperature, water deg. fahrenheit | 1 | 0 | 0 | ||
| Coliform, fecal general | 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
- 3Single-event violations
| Date | What EPA recorded | Agency |
|---|---|---|
| August 9, 2023 | WW SSO - Discharge to Waters | ST6 |
| June 13, 2022 | WW SSO - Discharge to Waters | ST6 |
| September 8, 2021 | Permit Violations - Violation Specified in Comment | 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 WI0021181 there.
Nearby on the register
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- Every permit record in Oconomowoc, A to Z
- Discharge permits in Wisconsin
- Every permit record in Wisconsin, A to Z
Figures from EPA’s ICIS-NPDES download, loaded September 14, 2026.