Clean Water Act discharge permit · NPDES IL0066257
MCHENRY - SOUTH WWTP, Mchenry, IL: NPDES IL0066257 discharge permit, effluent exceedances, inspections, penalties
- Administratively continuedPermit status
- MajorDischarger class
- 31Pollutants under a numeric limit
- 3Pollutants with an effluent exceedance
MCHENRY - SOUTH WWTP, held by MCHENRY, CITY OF, holds NPDES permit IL0066257, which discharges to Fox River. EPA’s file records it issued October 14, 2015 and expiring October 31, 2020. The status and dates are as EPA’s permit file stood when Velarion loaded it (October 14, 2026); EPA’s free Detailed Facility Report on ECHO carries the permit’s current standing.
Identity
| Facility as filed | MCHENRY - SOUTH WWTP |
|---|---|
| Permittee as filed | MCHENRY, CITY OF |
| NPDES ID | IL0066257 |
| 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 | October 14, 2015 |
| Expiration date | October 31, 2020 |
| Address | Mchenry, IL 60050 |
| Receiving water | FOX RIVER |
| Receiving water impaired | 303(D) Listed |
| Subwatershed | Griswold Lake-Fox River (HUC 071200061102) |
| Program components on file | POTW, Pretreatment |
| SIC | 4952 – Sewerage Systems |
Cited to the EPA ICIS-NPDES permit file (ECHO download) and EPA’s NAICS/SIC and component files, the same download.
Effluent limits and exceedances
- 32Pollutants on file
- 31Under a numeric limit
- 32With a violation of any kind
- 3With 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 |
|---|---|---|---|---|---|
| Nitrogen, ammonia total [as N] | 40 | 16 | 14 | April 30, 2026 | 196% over the limit |
| Solids, total suspended | 5 | 12 | 6 | May 31, 2020 | 43% over the limit |
| Coliform, fecal general | 1 | 4 | 3 | May 31, 2020 | 150% over the limit |
| Phosphorus, total [as P] | 2 | 12 | 0 | ||
| Oxygen, dissolved [DO] | 5 | 8 | 0 | ||
| Flow, in conduit or thru treatment plant | 4 | 6 | 0 | ||
| Silver, total [as Ag] | 2 | 6 | 0 | ||
| Zinc, total [as Zn] | 2 | 6 | 0 | ||
| Selenium, total [as Se] | 2 | 6 | 0 | ||
| Phenolics, total recoverable | 2 | 6 | 0 | ||
| Oil & Grease | 2 | 5 | 0 | ||
| Cyanide, total [as CN] | 2 | 5 | 0 | ||
| Fluoride, total [as F] | 2 | 5 | 0 | ||
| Arsenic, total [as As] | 2 | 5 | 0 | ||
| Barium, total [as Ba] | 2 | 5 | 0 | ||
| Cadmium, total [as Cd] | 2 | 5 | 0 | ||
| Chromium, hexavalent [as Cr] | 2 | 5 | 0 | ||
| Chromium, total [as Cr] | 2 | 5 | 0 | ||
| Copper, total [as Cu] | 2 | 5 | 0 | ||
| Iron, total [as Fe] | 2 | 5 | 0 | ||
| Iron, dissolved [as Fe] | 2 | 5 | 0 | ||
| Lead, total [as Pb] | 2 | 5 | 0 | ||
| Manganese, total [as Mn] | 2 | 5 | 0 | ||
| Nickel, total [as Ni] | 2 | 5 | 0 | ||
| Mercury, total [as Hg] | 2 | 5 | 0 | ||
| BOD, carbonaceous [5 day, 20 C] | 4 | 4 | 0 | ||
| Cyanide, free [amenable to chlorination] | 2 | 3 | 0 | ||
| pH | 2 | 2 | 0 | ||
| BOD, 5-day, 20 deg. C | 1 | 2 | 0 | ||
| Cyanide, weak acid, dissociable | 0 | 2 | 0 | ||
| Nitrogen, total [as N] | 2 | 1 | 0 | ||
| Chlorine, total residual | 1 | 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
- 1Single-event violations
| Date | What EPA recorded | Agency |
|---|---|---|
| January 14, 2026 | Dry-weather SSO, no discharge to waters of the U.S., that may endanger health or the environment | 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
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, IL0066257.
Start the watch
- One permit holder — $99/month
- One watershed — $2,990/year
- One state — $4,990/year
- The whole register — $18,000/year
How we handle your data → Privacy
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 IL0066257 there.
Nearby on the register
- Discharge permits in Mchenry
- Every permit record in Mchenry, A to Z
- Discharge permits in Illinois
- Every permit record in Illinois, A to Z
Figures from EPA’s ICIS-NPDES download, loaded October 14, 2026.