Ohio NPDES Wastewater Compliance Report
Fiscal year 2026 to date · October 2025 – May 2026
Every permitted wastewater discharger in Ohio files discharge monitoring reports (DMRs) into a public federal database. Almost nobody reads it. This report summarizes what that record says about the state as a whole — aggregate numbers only, computed directly from EPA's published files, with full methodology below so anyone can reproduce every figure.
We deliberately name no facilities here. Self-reported monitoring data contains errors and lags, an exceedance is not an enforcement finding, and many reported items are resolved or corrected later. The record deserves attention, not a blacklist. Definitions and caveats are at the end.
The fiscal year so far, in five numbers
Exceedances by monitoring month
June is partial: reports for June monitoring periods were just beginning to arrive when this snapshot was taken (July 13, 2026). That is the reporting lag, visible live.
The ten most-violated parameters
| Parameter | Exceedances | Permits affected |
|---|---|---|
| Nitrogen, ammonia total [as N] | 1,882 | 428 |
| Solids, total suspended | 1,563 | 452 |
| BOD, carbonaceous [5-day, 20 °C] | 884 | 285 |
| E. coli (MTEC-MF) | 345 | 191 |
| Phosphorus, total [as P] | 318 | 78 |
| pH | 146 | 107 |
| Dissolved oxygen | 129 | 85 |
| Copper, total recoverable | 111 | 23 |
| Mercury, total low level | 95 | 49 |
| BOD, 5-day, 20 °C | 90 | 19 |
The top of this table — ammonia, suspended solids, carbonaceous BOD, E. coli — is dominated by municipal sewage treatment works, which make up most NPDES permits. Industrial signatures sit further down: metals such as copper and mercury, dissolved solids, and oil & grease (40 exceedances across 25 permits this fiscal year, concentrated at metalworking and food-processing sites).
What else the record shows
- Missing reports are their own signal. 298 permits — nearly one in ten — have monitoring reports recorded as not received when due (EPA codes D80/D90), accounting for 10,696 expected measurements. A report that never arrived says as much about a monitoring program as a failed one.
- The record is faster than its reputation. Half of all measurements appear in the public file within 15 days of the monitoring period ending; 90% within 20 days. The common belief that this data is "months stale" is not what the file shows — most of it is fresh, and almost nobody is watching.
- Exceedances are routine, not exceptional. A third of all reporting permits recorded at least one this fiscal year. Most are resolved through the ordinary permit process and never involve formal enforcement.
Methodology — reproduce every number
Source file:
https://echo.epa.gov/files/echodownloads/NPDES_by_state_year/OH_FY2026_NPDES_DMRS_LIMITS.zip
(EPA ECHO downloads, ICIS-NPDES), retrieved 2026-07-13. SHA-256 of the retrieved
archive: 8b2af64cfd8ea4dac15d0fee24243a09dd26b6df1113907d81fa44149da910b1.
Definitions. "Exceedance" = a DMR row EPA marks with violation
code E90 (effluent limit violation). "Missing report" = codes D80/D90 (DMR
non-receipt). "Permits reporting" = distinct permit numbers with any DMR row in the
file. Receipt lag = VALUE_RECEIVED_DATE minus
MONITORING_PERIOD_END_DATE, negative values excluded.
Coverage. Federal fiscal year 2026 (monitoring periods from October 1, 2025). Data complete through May 31, 2026; June 2026 partial at retrieval. EPA revises these files continuously — a later download will differ.
Caveats. DMR data is self-reported by permittees and contains transcription and units errors; EPA's own documentation says so, and we have found examples. An E90 flag is a database record, not a legal finding, and may be superseded, corrected, or resolved. Nothing here states or implies that any facility is currently in violation.
About this report
Published by PlantSignal, a research service that monitors public environmental records for industrial equipment and service vendors. We publish aggregate statistics and methodology openly; we do not publish facility-level compliance lists. Questions, corrections, or a request for the underlying computation: [email protected].