You submitted the DMR, and then you found the mistake. Maybe it was a transposition — 54 where it should have been 45. Maybe you realized you used the wrong calculation method, or left a parameter blank. Whatever the error, the anxiety that follows is real. NPDES reporting errors feel serious, and they are — but they are also fixable.
Here is the first thing you need to know: submitted DMRs can be corrected in NetDMR. The Integrated Compliance Information System (ICIS) will update when you resubmit. Regulators understand that data entry errors happen, and the system is specifically designed to accommodate amendments. A corrected DMR is not an admission of wrongdoing — it is an accurate record, which is exactly what the regulations require.
The second thing you need to know: do not wait. Errors that sit uncorrected have a way of compounding. An uncorrected value might generate an automated violation flag in ICIS. It might trigger a follow-up from your state agency. It might show up in a compliance schedule review at exactly the wrong moment. The sooner you submit a corrected DMR, the simpler the resolution. Even corrections made months or years after the fact are accepted in most states — but the earlier you act, the cleaner the record.
Do not leave a known DMR error in place and hope it goes unnoticed. ICIS data is reviewed during inspections, compliance schedule audits, and permit renewal evaluations. An uncorrected data entry mistake that later surfaces looks far worse than a documented, proactive correction made shortly after discovery.
Can You Always Correct a Submitted DMR?
In most cases, yes. NetDMR allows amendments as long as the reporting period is still "open" in the system. An open period means the system has not locked the data for that cycle. In practice, many periods remain editable for months or even years after the submission deadline — but this varies by state.
Some states lock reporting periods after a defined interval — often 60 to 90 days after the submission due date. Others may lock periods after an audit or enforcement action has been initiated. If a period is locked, you will not see an "Amend" or "Edit" option on the submitted DMR. In that case, you will need to contact your state NPDES coordinator or data management contact and request that they unlock the period before you can submit a correction.
If you are unsure whether your state has locked the reporting period — or if the DMR is more than 90 days old — call your state contact first. Explain that you have identified a data error and need to submit a corrected DMR. They will tell you whether you can proceed directly in NetDMR or whether they need to unlock the period on their end. This one call can save significant back-and-forth.
It is also worth noting that some states have delegated NPDES programs with their own data portals that feed into ICIS. If your state uses a state-specific reporting system rather than NetDMR directly, the amendment process may differ slightly — but the underlying logic is the same. Contact your state agency if you are uncertain which system governs your permit.
What Types of Errors Can Be Corrected?
Almost any data entry error on a submitted DMR can be corrected through an amendment. Common scenarios include:
- Wrong value entered — A transposition error (e.g., 54 instead of 45), a decimal point in the wrong place, or a value entered in the wrong row or column.
- Unit conversion error — A result reported in mg/L when your permit requires lbs/day, or vice versa, with the conversion math applied incorrectly or not at all.
- Wrong calculation method — Using an arithmetic mean where your permit specifies a geometric mean (common for fecal coliform and E. coli reporting), or using the wrong averaging period.
- Non-detect entered as zero — Reporting a non-detect result as 0 instead of the correct convention for your state (often half the method detection limit, or simply flagged as "ND" with the appropriate qualifier code).
- Missing parameter value — A required parameter was left blank on the submitted DMR, either because the sample result was not yet available or was overlooked during data entry.
- Wrong NODI code applied — An incorrect "No Data Indicator" was entered — for example, using NODI "C" (no discharge) when sampling actually occurred and results are available.
- Wrong sample type reported — A grab sample reported as a composite, or a composite reported as a grab, which may affect how the result is evaluated against your permit limits.
- Duplicate submission — The same DMR was submitted twice for the same reporting period, creating duplicate records in ICIS that need to be resolved.
All of these are legitimate reasons to submit a corrected DMR. None of them are unusual — experienced compliance staff encounter all of them at some point.
Step-by-Step: Correcting a DMR in NetDMR
The amendment process in NetDMR is straightforward once you know where to look. Work through these steps in order.
Log into NetDMR at cdx.epa.gov. Use your CDX credentials. Once logged in, navigate to your facility and select your NPDES permit. From the permit dashboard, locate the DMR for the reporting period that contains the error. DMRs are typically organized by monitoring period end date, so confirm you are looking at the correct month and year.
Check the DMR status indicator. NetDMR displays a status for each submitted report. If the status shows "Submitted" or "Pending", you can likely amend it directly. If the status shows "Accepted" or "Locked", the period may have been closed by your state, and you will need to contact your state NPDES coordinator to request the period be unlocked before proceeding. Do not attempt workarounds — work through proper channels.
Click "Amend" or "Edit" on the submitted DMR. This button appears on the DMR detail view when the period is editable. When you click it, NetDMR creates a new version of the DMR — your original submission is preserved in the system as version 1 and remains part of the permanent record. You will be working in version 2 (or higher, if previous amendments have already been made). This versioning is intentional: regulators can see the full history of what was submitted and when.
Make your corrections — and only your corrections. Change the fields that contain errors. Do not re-enter or modify values that were correct on the original submission; unnecessary changes introduce confusion and may raise questions during a future review. If you are correcting an individual sample result that feeds into a monthly average or maximum, confirm that the calculated summary values (average, maximum) update automatically to reflect the corrected data.
Review the corrected values carefully before resubmitting. Read through every field you changed — and the fields that depend on them. If you corrected individual sample values, verify that any averages or maximums displayed on the DMR now reflect the corrected inputs. If you corrected a unit conversion, confirm that all downstream calculated values used the right conversion factor. A second set of eyes at this stage is worth the time.
Add a comment in the remarks or comments field explaining what was corrected and why. This step is critical and often skipped. A clear, factual note — for example, "Corrected TSS daily maximum value from 54 mg/L to 45 mg/L. Original value was a transposition error. Lab result sheet dated [date] confirms 45 mg/L." — creates a documented audit trail that follows the corrected DMR permanently. If anyone ever questions the amendment, this note is your first line of explanation. Be factual, be specific, and keep it professional.
Re-sign and submit using your CDX credentials. Like the original submission, amended DMRs require a valid electronic signature. You will be prompted to enter your CDX password and confirm the submission. Once submitted, the corrected DMR (version 2 or higher) becomes the current, authoritative record in ICIS — replacing the prior version for compliance evaluation purposes while the original version remains in the audit history.
Allow 24 to 48 hours for the corrected DMR to propagate through ICIS and appear in your state agency's system. If you need to confirm receipt, contact your state NPDES coordinator with your permit number, reporting period, and the date and time of your corrected submission.
Will the Correction Remove the Violation?
This is the question operators most want answered, and it deserves a careful response.
If the original error created a false violation — meaning the value you entered exceeded your permit limit, but the correct value does not — then yes, submitting the corrected DMR should cause ICIS to clear the violation once the corrected data is processed. The system evaluates reported values against permit limits, so if the corrected value falls within your limits, the automated violation flag should be removed. This is one of the clearest cases for acting quickly: a data entry mistake that generates a false violation is resolved cleanly once the accurate value is on record.
However, if you made a reporting error but the correct value still exceeds your permit limit, the violation is real and will remain in ICIS after correction. The corrected DMR does not make the violation disappear — it simply ensures the accurate data is on record. This is still the right thing to do. Accurate data, even when it reflects an exceedance, demonstrates good-faith recordkeeping and regulatory compliance with your reporting obligations. An accurate record of a genuine exceedance is far better than an inaccurate record that misrepresents your effluent quality.
Regulators distinguish between facilities that identify and correct their own reporting errors and facilities where errors are discovered during inspections. Proactive corrections — even those that confirm a genuine exceedance — are viewed more favorably than corrections made under regulatory pressure. Your correction creates a documented record of good-faith compliance behavior.
When to Notify Your State Regulator
Correcting a DMR in NetDMR and notifying your state regulator are two separate obligations — and in some situations, both are required.
If your original DMR reported data that showed no violation, but the corrected values reveal an exceedance that was not previously reported, you likely have a notification obligation under your permit. Most NPDES permits include standard conditions that require the permittee to notify the permitting authority within a specified timeframe — often 24 hours of becoming aware of a significant violation or noncompliance event, with a written follow-up report within five days.
Pull out your permit and read the standard conditions section carefully. Look for language about "noncompliance reporting," "notification requirements," or "upset and bypass reporting." These sections will specify exactly what triggers a notification obligation and what form that notification must take.
Submitting a corrected DMR in NetDMR does not automatically notify your state regulator. If your corrected data reveals a previously unreported violation, the permit notification requirement is a separate obligation that you must fulfill directly — typically by phone or email to your state contact. Check your permit's standard conditions and act accordingly.
If you are unsure whether a notification obligation applies to your specific situation, err on the side of transparency. A brief, proactive call to your state coordinator explaining that you have identified and corrected a reporting error — and describing what the corrected data shows — will almost always go over better than silence.
Document Everything in Your Internal Records
Once you have submitted the corrected DMR and fulfilled any applicable notification requirements, document the entire event in your internal compliance records. This documentation is your protection if the correction is ever questioned during an inspection, enforcement proceeding, or permit renewal.
Your internal record should include:
- A screenshot or PDF export of the original submitted DMR (version 1)
- A screenshot or PDF export of the corrected submitted DMR (the amended version)
- The date and time the correction was submitted
- A brief written description of what was corrected and why — mirroring the comment you entered in the NetDMR remarks field
- The underlying source document that confirms the correct value (lab sheet, field log, chain of custody record)
- Any correspondence with your state regulator related to the correction
Store this documentation with your DMR records for the retention period specified in your permit — typically at least three years, and often longer. If a NetDMR correction is ever raised in an audit or inspection, your ability to produce this documentation on the spot demonstrates exactly the kind of systematic, organized compliance program that regulators want to see.
Making a mistake on a DMR is not the end of the world. What matters is how you handle it. Correct the record accurately, document what happened, notify your regulator if required, and move forward. The system is designed to accommodate corrections, and the regulators who administer it have seen this situation many times. Your job is to get the accurate data on record — and the process for doing that is well within your reach.
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