When a monitoring result exceeds an NPDES permit effluent limit, the clock starts immediately. You have 24 hours for oral notification, 5 days for written follow-up, and a limited window to investigate, implement corrective actions, and document everything before the DMR is due. A structured exceedance response process — supported by water quality software — ensures nothing is missed and creates the documented compliance record that regulators expect.
The Exceedance Response Timeline
Immediate: Detect the Exceedance
The sooner you know about an exceedance, the more time you have to respond. Software compares every lab result to the applicable permit limit the moment EDD data is imported, flagging exceedances and sending automatic email alerts to responsible personnel. Without software, exceedances may not be discovered until someone manually reviews a lab report — potentially days or weeks later.
Within 24 Hours: Oral Notification
Standard NPDES permit conditions require oral notification to the permitting authority within 24 hours of becoming aware of noncompliance that may endanger health or the environment. This includes exceedances of daily maximum limits for toxic pollutants and any upset or bypass conditions. Software tracks the notification deadline and records the date, time, person contacted, and summary of the notification.
Within 5 Days: Written 5-Day Letter
A written follow-up must be submitted within 5 days of becoming aware of the exceedance. The 5-day letter should include:
- Description of the noncompliance (parameter, outfall, measured value, permit limit)
- Date and duration of the exceedance
- Cause of the noncompliance (known or suspected)
- Steps taken to reduce, eliminate, or prevent recurrence
- Period of noncompliance (if ongoing, estimated date of return to compliance)
Investigation: Root Cause Analysis
A thorough root cause investigation documents what caused the exceedance and informs corrective actions. Common causes include treatment process upsets, equipment failures, unusual influent loading, storm events, sampling or analytical errors, and upstream spills or discharges. Software provides historical trend data and operational records to support the investigation.
Corrective Actions: Implement and Track
Corrective actions should address both the immediate cause and prevent recurrence. Examples include adjusting chemical dosing, repairing equipment, increasing monitoring frequency, modifying operational procedures, or upgrading treatment capacity. Software assigns corrective actions to responsible personnel with due dates and tracks them to completion.
DMR Reporting: Narrative Explanation
The exceedance must be reported on the DMR for the monitoring period in which it occurred. The DMR narrative should be factual and concise: identify the parameter and outfall, state the measured value and limit, describe the cause, and summarize corrective actions. Avoid speculative language, minimize blame, and focus on documented facts and actions taken.
How Software Manages the Exceedance Workflow
Automatic Detection & Alerting
Every result is compared to the applicable permit limit on import. Exceedances trigger immediate email notifications to the environmental manager, plant operator, and any other designated personnel. No manual checking, no waiting for monthly report preparation to discover the problem.
Exceedance Record Management
Each exceedance creates a structured record: parameter, outfall, measured value, permit limit, percent over limit, date, and responsible person. The record tracks notification status (oral notification date, 5-day letter date), root cause documentation, corrective actions, and resolution status.
Corrective Action Tracking
Assign corrective actions with due dates, responsible parties, and completion requirements. Track progress, document evidence of completion, and generate reports showing open and closed corrective actions. This creates the compliance record that demonstrates good-faith effort to regulators.
Historical Exceedance Reporting
Generate reports showing all exceedances by parameter, outfall, time period, or cause category. Identify recurring problems, track exceedance frequency trends, and evaluate whether corrective actions are effective at preventing recurrence.
Related Ecesis Solutions
Water Quality Software
Lab imports, data validation, permit tracking and DMR reporting.
Incident Reporting
Document spills, releases and environmental incidents.
Task Tracking
Assign corrective actions with due dates and accountability.
Compliance Obligations
Track all regulatory obligations and recurring deadlines.
Inspections & Audits
Mobile field inspections with corrective action tracking.
Document Control
Manage 5-day letters, SOPs, and compliance documents.
Ready to Automate Your Exceedance Response?
Call (720) 547-5102 or click below to see exceedance management in action.
