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Clean Water Act discharge permit · NPDES IA0031186

GRINNELL, CITY OF STP, Grinnell, IA: NPDES IA0031186 discharge permit, effluent exceedances, inspections, penalties

GRINNELL, CITY OF STP, held by CITY OF GRINNELL, holds NPDES permit IA0031186. EPA’s file records it issued January 1, 2020 and expiring December 31, 2024.

GRINNELL, CITY OF STP, Grinnell, Iowa: Individual permit IA0031186, held by CITY OF GRINNELL; Publicly owned treatment works; Effective; issued January 1, 2020, term to December 31, 2024, by STA; Sewage Treatment Facilities.

  • Nitrogen, ammonia total [as N]: 48 limits, 42 violations of any kind, 30 effluent exceedances, latest July 31, 2021, largest 99% over the limit.
  • Flow, in conduit or thru treatment plant: 0 limits, 23 violations of any kind, 21 effluent exceedances, latest May 31, 2013, largest 25% over the limit.
  • BOD, carbonaceous [5 day, 20 C]: 4 limits, 24 violations of any kind, 4 effluent exceedances, latest October 31, 2015, largest 34% over the limit.
  • Solids, total suspended: 9 limits, 22 violations of any kind, 2 effluent exceedances, latest December 31, 2016, largest 33% over the limit.
  • pH: 5 limits, 11 violations of any kind, 1 effluent exceedance, latest April 30, 2007.
  • Oxygen, dissolved [DO]: 1 limit, 6 violations of any kind, 1 effluent exceedance, latest August 31, 2022, largest 29% over the limit.
  • Toxicity [acute], Ceriodaphnia dubia: 1 limit, 5 violations of any kind, 0 effluent exceedances.
  • Toxicity [acute], Pimephales promelas [Fathead Minnow]: 1 limit, 5 violations of any kind, 0 effluent exceedances.
  • E. coli: 1 limit, 2 violations of any kind, 0 effluent exceedances.
  • Nitrogen, total [as N]: 10 limits, 0 violations of any kind, 0 effluent exceedances.
  • Phosphorus, total [as P]: 10 limits, 0 violations of any kind, 0 effluent exceedances.
  • BOD, 5-day, 20 deg. C: 5 limits, 0 violations of any kind, 0 effluent exceedances.
  • Nitrogen, Kjeldahl, total [as N]: 5 limits, 0 violations of any kind, 0 effluent exceedances.

Iowa holds 734 Publicly owned treatment works coverages of this permit type in EPA’s file; 496 were issued before IA0031186. CITY OF GRINNELL holds 2 permits in Iowa.

Other permits held by CITY OF GRINNELL

Coverages issued nearest IA0031186

GRINNELL, CITY OF STP among its neighbors

EPA’s permit file holds 1 discharge permits in the Sugar Creek subwatershed (HUC 070801060203), IA0031186 among them. Its county holds 12, 1 of them major permits; IA0031186 is a major permit.

Identity

Facility as filedGRINNELL, CITY OF STP
Permittee as filedCITY OF GRINNELL
NPDES IDIA0031186
Permit statusEffective
Permit typeIndividual permit
Discharger classMajor discharger
Facility typePublicly owned treatment works
ProgramPublicly owned treatment works
IssuedJanuary 1, 2020
Expiration dateDecember 31, 2024
Issuing agencySTA
AddressGrinnell, IA 50112
SubwatershedSugar Creek (HUC 070801060203)
Program components on fileBiosolids, POTW
NAICS221320 – Sewage Treatment Facilities
SIC4952 – Sewerage Systems

Effluent limits and exceedances

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 measureLimitsViolations, any kindEffluent exceedancesLatest exceedanceLargest exceedance, as filed
Nitrogen, ammonia total [as N]484230July 31, 202199% over the limit
Flow, in conduit or thru treatment plant02321May 31, 201325% over the limit
BOD, carbonaceous [5 day, 20 C]4244October 31, 201534% over the limit
Solids, total suspended9222December 31, 201633% over the limit
pH5111April 30, 2007
Oxygen, dissolved [DO]161August 31, 202229% over the limit
Toxicity [acute], Ceriodaphnia dubia150
Toxicity [acute], Pimephales promelas [Fathead Minnow]150
E. coli120
Nitrogen, total [as N]1000
Phosphorus, total [as P]1000
BOD, 5-day, 20 deg. C500
Nitrogen, Kjeldahl, total [as N]500

Inspections, violations and enforcement

EPA’s single-event violation file, as loaded, holds no violation for NPDES IA0031186.

Inspections

EPA’s inspection file holds no inspection for NPDES IA0031186.

Formal enforcement and penalties

0 formal actions, 0 of them with a penalty assessed. Federal and state penalties are separate figures from separate authorities and are shown as each was filed, never added together.

Informal enforcement

EPA’s informal enforcement file holds no action for NPDES IA0031186.

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Nearby on the register

Figures from EPA’s ICIS-NPDES download, loaded October 14, 2026.

What this page shows

This public-records page covers the NPDES discharge permit IA0031186 for the Grinnell, City of STP facility in Grinnell, Iowa, held by the City of Grinnell, with a status of Effective and a Major discharger class. The page lists 13 pollutants on file, 12 under a numeric limit, 9 with a violation of any kind, and 6 with an effluent exceedance.