NPDES Monitoring Data Download Help

The NPDES Monitoring Data Download provides an easy-to-read file for all available permit limit and discharge information for facilities regulated under the CWA National Pollution Discharge Elimination System (NPDES) in a downloadable spreadsheet format (XLSX) or CSV file. The download files organize NPDES pollutant permit limits and associated discharge monitoring data in tables by outfall for a single facility within a selected date range. 

Search Criteria Help

Monitoring Period Range
Select the time period (month and year) for the permit limit and reported discharge data. Dates available for selection are January 2007 to present.  Note that depending on when the permit became effective, a permit may not have data for all or part of the selected time period.
Facility Identification
You may search for one NPDES permit at a time using one of the search criteria below. 
NPDES ID
A nine-character code used to uniquely identify a permitted NPDES facility. The NPDES permit program regulates the direct discharge of pollutants into U.S. waters.
FRS ID
A 12-character code used to uniquely identify a facility site within the EPA Facility Registry Service (FRS) database.

Download File Structure

The spreadsheet format follows a repeating structure, with each table defined by the outfall, monitoring location, and limit set identifier.

 Each column in the table contains the time series of pollutant measurements, or Discharge Monitoring Reports (DMRs), taken at the outfall and monitoring location applicable to the limit set. The column header includes the following information:

  • Parameter name, e.g., "Solids, suspended percent removal"
  • Permit limit value and units; and
  • Measurement statistical basis, e.g., DAILY MX = Daily Maximum.

Each row corresponds to one monitoring period. The table cells display the reported measurement value or No Data Indicator (NODI) code.

A blank cell within the table indicates that no measurements were reported for the parameter at the applicable outfall, monitoring location, and limit set during the monitoring period.

Data Dictionary

Outfall/Permit Feature ID
A three-character code in ICIS-NPDES that identifies the point of discharge (e.g., outfall) for a facility. A NPDES permit may have multiple points of discharge.
Monitoring Location
A single-character code in ICIS-NPDES that indicates the sampling location for each pollutant measurement.
Limit Set
A single-character code in ICIS-NPDES that groups limits that are set on a similar basis (e.g., monthly vs. annual limits, seasonal limits)
No Data Indicator (NODI)
The unique code in ICIS-NPDES indicating why no DMR value was submitted by the permittee. Refer to the Loading Tool Glossary for a list of NODI codes and descriptions.

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