Clean Water Act discharge permit · NPDES MIG670386
SOUTHWEST GAS STORAGE COMPANY-HOWELL, Howell, MI: NPDES MIG670386 discharge permit, effluent exceedances, inspections, penalties
- EffectivePermit status
- MinorDischarger class
- 15Pollutants under a numeric limit
- 1Pollutants with an effluent exceedance
SOUTHWEST GAS STORAGE COMPANY-HOWELL, held by Southwest Gas Storage Company, holds NPDES permit MIG670386, which discharges to Marion And Genoa Drain. EPA’s file records it issued June 17, 2025 and expiring April 1, 2028. 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 | SOUTHWEST GAS STORAGE COMPANY-HOWELL |
|---|---|
| Permittee as filed | Southwest Gas Storage Company |
| NPDES ID | MIG670386 |
| Permit status | Effective |
| Permit type | Coverage under a general permit |
| Discharger class | Minor discharger |
| Facility type | Not a publicly owned treatment works |
| Issued | June 17, 2025 |
| Expiration date | April 1, 2028 |
| Issuing agency | State |
| Address | Howell, MI 48843 |
| Receiving water | Marion and Genoa Drain |
| Receiving water impaired | 303(D) Listed |
| Subwatershed | Marion and Genoa Drain-South Branch Shiawasee River (HUC 040802030101) |
Cited to the EPA ICIS-NPDES permit file (ECHO download).
Effluent limits and exceedances
- 15Pollutants on file
- 15Under a numeric limit
- 15With a violation of any kind
- 1With 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 |
|---|---|---|---|---|---|
| Chlorine, total residual | 6 | 7 | 1 | September 30, 2025 | 32% over the limit |
| Solids, total suspended | 6 | 6 | 0 | ||
| Benzene, ethylbenzene, toluene, xylene combination | 6 | 6 | 0 | ||
| Toluene | 6 | 6 | 0 | ||
| Benzene | 6 | 6 | 0 | ||
| Ethylbenzene | 6 | 6 | 0 | ||
| Xylenes [total], dry weight | 6 | 6 | 0 | ||
| Flow rate | 4 | 4 | 0 | ||
| pH | 4 | 4 | 0 | ||
| Chlorination duration | 4 | 4 | 0 | ||
| Oxygen, dissolved [DO] | 2 | 2 | 0 | ||
| Oil & Grease | 2 | 2 | 0 | ||
| Equipment inspection - visual | 2 | 2 | 0 | ||
| Volume, total | 2 | 2 | 0 | ||
| Outfall observation,visual, y/n response | 2 | 2 | 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 |
|---|---|---|
| August 21, 2025 | Reporting Violations - Late Submittal of DMRs | ST6 |
| July 21, 2025 | Reporting Violations - Late Submittal of DMRs | 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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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 MIG670386 there.
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Figures from EPA’s ICIS-NPDES download, loaded September 15, 2026.