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Discharge Monitoring Report (DMR) Pollutant Loading Tool

The Loading Tool is being transitioned into ECHO to increase user access to data and streamline site maintenance. The beta version is now available for testing. EPA plans to retire this site in late November 2017. Current site functionality will be available in ECHO.

Note: The tool uses discharge monitoring report (DMR) data from ICIS-NPDES to calculate pollutant discharge amounts. EPA has verified the accuracy of the tool’s calculations. EPA has also performed a limited review of the underlying data that has focused on facilities with the largest amounts of pollutant discharges. Due to the large amount of DMR data, some errors exist in ICIS-NPDES DMR data. Please see the User Guides page for instructions on how to use the tool and how to correct errors in ICIS-NPDES. The tool also uses wastewater pollutant discharge data from the Toxics Release Inventory (TRI). Contact Us with any comments or questions about the tool, and sign up for our e-mail news bulletin to be notified when new data, enhancements, or training materials become available.


The Discharge Monitoring Report (DMR) Pollutant Loading Tool is designed to help you determine who is discharging, what pollutants they are discharging and how much, and where they are discharging. The tool calculates pollutant loadings from permit and DMR data from EPA's Integrated Compliance Information System for the National Pollutant Discharge Elimination System (ICIS-NPDES). Data are available from the year 2007 to the present. Pollutant loadings are presented as pounds per year and as toxic-weighted pounds per year to account for variations in toxicity among pollutants. The tool ranks dischargers, industries, and watersheds based on pollutant mass and toxicity, and presents “top ten” lists to help you determine which discharges are important, which facilities and industries are producing these discharges, and which watersheds are impacted.

The tool also includes wastewater pollutant discharge data from EPA’s Toxics Release Inventory (TRI). Data are available for the years 2007 to the most recent reporting year. Users can search TRI data to find the facilities with the largest pollutant discharges to surface waters or sewage treatment plants (a.k.a. Publicly Owned Treatment Works or “POTWs”). Users can also compare the DMR data search results against TRI data search results and vice versa. The tool clearly labels the source of data when displaying search results but does not mix TRI or DMR data when calculating pollutant discharges.

If this is your first time using the tool, you might want to start with the EZ Search (DMR data) or the TRI Search (TRI data). If you need more flexibility with your searches, try the Advanced Search (DMR data). If you have additional questions or would like more information about the tool, you can access more detailed information in the User Guides/Tech Documents tab.

Read on to learn more about:

How to Navigate the Tool

This tool provides several search options to help you access wastewater pollutant discharge data, for example:

  • If you are a general user, you can use the EZ Search or TRI Search to quickly find discharge monitoring data or TRI data based on simple searches.

  • If you are a technical user (e.g., NPDES permit writer, researcher, watershed modeler, or regulatory agency), you can use the Advanced Search to access more detailed discharge monitoring data that you can download in a comma-separated value (CSV) file for further analysis in your own software application.

You can navigate the Loading Tool using the following tabs:

  • EZ Search: Users can perform simple searches using DMR data. Results are displayed on a Web page in “top ten” lists to help you determine which discharges are important, which facilities and industries are producing these discharges, and which watersheds are impacted.

  • TRI Search: Similar search interface and display results as EZ Search but the data source is TRI data.

  • Data Explorer: Users can create a thematic map of the United States in which states are shaded in blue in proportion to the selected search criteria. For example, the user can visually see the number of POTWs in each state, with states shaded in dark blue having the greatest number of POTWs.

  • Facility Search: Provides direct access to facility-level information, one facility at a time, using the facility name or a unique identifier (e.g., NPDES ID, TRI ID, FRS ID).

  • Advanced Search: Designed for technical users and provides increased flexibility on searching DMR data. Results are provided as a comma separated value (CSV) file for post-processing by the user.

  • Everyday Searches: Provides access trend charts and other 'canned' searches (by geographic location, industry sector, and/or pollutant) of DMR data that are often used by technical users. In particular, the “Facility Loading Calculations” on this tab will detail exactly how the tool calculates annual pollutant loads using DMR data.

  • User Guides/Technical Documents: Provides the instructions, guides, and metadata to assist users with the Loading Tool.

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