NODI Codes Explained

NODI Codes Explained | ADEQ

Revised On: Sep. 9th, 2026 - 03:24 pm

What are NODI Codes?

A No Data Indicator (NODI) code is standard code/description that indicates the reason “No Discharge” or “No Data” was reported on a Discharge Monitoring Report (DMR). A NODI code must be used on a DMR when a permittee does not have a numeric value to report for a parameter.

Why do I have to use a NODI code? 

ADEQ’s electronic permitting portal, myDEQ, and EPA’s electronic reporting systems do not allow partial or incomplete submissions. To explain missing data, permittees use NODI codes. These standardized codes allow ADEQ and the Environmental Protection Agency (EPA) compliance databases to automatically process the reason for missing numeric values. 

Which codes are active?

The EPA determines which NODI codes are available (active) nationwide for state and federal permits. Arizona does not support any state-specific NODI codes. You can view active codes on the EPA website: ICIS-NPDES DMR Summary and Data Element Dictionary | ECHO | US EPA

Will I get a violation if I use a NODI code?

It depends on the circumstance.

No Violation: No potential violations will be flagged when collecting a stormwater sample isn't possible. For example, if you had no discharge for a monitoring period, reporting NODI C (No Discharge) will not flag a violation on your DMR.

Potential Deficiency: If monitoring was required but missed—such as due to a lost sample or operational delay—reporting a NODI code alerts regulatory databases and may result in a Notification of Potential Deficiency for the missed monitoring event.

How does ADEQ verify proper usage? 

ADEQ reviews laboratory reports and any additional comments submitted via the myDEQ portal to verify that NODI codes are applied correctly. If ADEQ has questions, they may contact the permittee for more information. 

Currently Active NODI Codes

To ensure you are entering the proper NODI code, refer to the following list of current active EPA NODI codes:

NODI Code	What does it mean?	When is it used?	Examples
2	Operation Shutdown	When there is an operation shutdown.	The operation was shut down.
9	Conditional Monitoring — Not Required This Period	Parameter must only be monitored in certain conditions. This can also be used for parameters with no approved laboratory method.	• Total residual chlorine was not required because UV was used for disinfection • No approved laboratory method exists (Tribulin).
B	Below Detection Limit/No Detection	When the result is less than the laboratory’s LOD/MDL.	Chlorine result is less than the method detection limit.
C	No Discharge (entire facility or entire monitoring point)	No discharge occurred during the reporting period. NOTE: You can enter NODI C only as part of the No Data reporting for the entire facility or an entire monitoring point.	All discharge was sent to reuse.
E	Failed to Sample/Required Analysis Not Conducted	Laboratory did not complete all of the required analyses.	• Omission of a parameter from the laboratory analysis. • Sample or laboratory analysis was not conducted.
N	Not Constructed	When the facility is not constructed.	Facility not constructed.
P	Laboratory Error or Invalid Test	There was a laboratory error or invalid test.	The laboratory sample was contaminated.
Q	Not Quantifiable	The result is greater than the LOD but less than the LOQ.	Laboratory reports cyanide result above the MDL but below the RL and uses an E4 data laboratory data qualifier indicated the results is estimated.
T	Environmental Conditions – Monitoring Not Possible	Environmental conditions prevent monitoring.	Weather event like flooding or snow.

Other NODI codes include:

3 – Special report attached
7 – No Influent
A – General permit exemption
F – Insufficient flow for sampling
I – Land Applied
R – Administratively resolved
W – Dry lysimeter/well
X – Parameter/value not reported