Clean Water Act discharge permit · NPDES IA0063401

DIAGONAL CITY OF STP, Diagonal, IA: NPDES IA0063401 discharge permit, effluent exceedances, inspections, penalties

Administratively continuedPermit status
MinorDischarger class
6Pollutants under a numeric limit
2Pollutants with an effluent exceedance

DIAGONAL CITY OF STP, held by CITY OF DIAGONAL, holds NPDES permit IA0063401. EPA’s file records it issued December 1, 2018 and expiring November 30, 2023. 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	DIAGONAL CITY OF STP
Permittee as filed	CITY OF DIAGONAL
NPDES ID	IA0063401
Permit status	Administratively continued (past its expiration date and still in force until reissued)
Permit type	Individual permit
Discharger class	Minor discharger
Facility type	Publicly owned treatment works
Program	Publicly owned treatment works
Issued	December 1, 2018
Expiration date	November 30, 2023
Issuing agency	STA
Address	Diagonal, IA 50845
Subwatershed	Squaw Creek-Grand River (HUC 102801010103)
NAICS	221320 – Sewage Treatment Facilities
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

6Pollutants on file
6Under a numeric limit
3With a violation of any kind
2With 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
pH	2	19	7	May 31, 2023
BOD, carbonaceous [5 day, 20 C]	5	18	5	December 31, 2021	22% over the limit
Solids, total suspended	5	13	0
Nitrogen, ammonia total [as N]	5	0	0
E. coli	3	0	0
Depth of pond or reservoir in feet	3	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

0Single-event violations

EPA’s single-event violation file, as loaded, holds no violation for NPDES IA0063401.

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 IA0063401 there.

Nearby on the register

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

This public-records page covers NPDES permit IA0063401 for DIAGONAL CITY OF STP in Diagonal, IA, held by CITY OF DIAGONAL, which EPA's file lists as issued December 1, 2018 and expiring November 30, 2023, with an administratively continued status as of October 14, 2026. The figures listed are 6 pollutants on file, 6 as the discharger class count, 2 pollutants under a numeric limit, and 2 pollutants with an effluent exceedance, within the Squaw Creek-Grand River watershed (HUC 102801010103).