NODI Codes Explained

NODI Codes Explained | ADEQ

Revised On: Sep. 15th, 2026 - 02:35 pm

What are NODI Codes?

A No Data Indicator (NODI) code is a 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 | View Active Codes >

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.
3	Special report attached	A special report is required to demonstrate that discharge values were in compliance. Not to be used when limits are exceeded.	A report is needed for complex calculations that demonstrate compliance with a flow-based limit, such as excess thermal load.
7	No Influent	The facility had no flow input, and therefore had no subsequent output for effluent assessment.	Alternatively, influent loading rates cannot be measured because of no influent. A wastewater treatment plant has no influent due to the town’s low seasonal occupancy.
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).
A	General permit exemption	The general permit provides an exemption from sampling under specific circumstances.	Facilities that discharge to non-WOTUS segments of one of the eight major rivers listed in A.R.S. §49-221(G)(1)(b) Waters or an ephemeral that may transport pollutants by stormwater to protected surface water, are not required to monitor for Total Suspended Solids (TSS) and turbidity as part of the routine analytical monitoring requirements.
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.
F	Insufficient flow for sampling	There is not enough discharge to collect a sample.	Effluent volume is too little to produce a steam deep enough to collect a valid sample.
I	Land Applied	Wastewater has been diverted to approved land application uses.	All wastewater during the monitoring period was directed to a public green space for irrigation.
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.
R	Administratively resolved	Circumstances outside the scope of other NODI codes have been discussed with ADEQ, and the submitter has been instructed by ADEQ to use this code.	Samples were able to be captured, but the results were strongly impacted by the aftermath of wildfires and not representative of normal discharge.
T	Environmental Conditions – Monitoring Not Possible	Environmental conditions prevent monitoring.	Weather event like flooding or snow.
W	Dry Lysimeter/well	Groundwater well is dry with no measurable moisture.	The device contains zero moisture during the scheduled monitoring cycle, making sample collection physically impossible.
X	Parameter/value not reported	The lab did not complete the requested tests for a parameter.	The permittee requests a measurement of total cyanide in its sample suite, but the laboratory did not provide results for cyanide.