Jump to main content or area navigation.

Contact Us

Discharge Monitoring Report (DMR) Pollutant Loading Tool

Note: The tool uses discharge monitoring report (DMR) data from ICIS-NPDES and PCS 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, additional errors exist in ICIS-NPDES and PCS. Please see the User Guide (29 pp, 2.6MB), Frequently Asked Questions and Answers, and Error Correction page for instructions on how to use the tool and how to correct errors in ICIS-NPDES and PCS. You can send an email to waterloadings@epa.gov with any comments or questions about the tool. You can sign up for our e-mail news bulletin and be notified when new data, enhancements, or training materials are available. The tool also uses wastewater pollutant discharge data from the Toxics Release Inventory (TRI).

About the Data

The Loading Tool uses discharge monitoring and permit data from PCS and ICIS-NPDES. PCS and ICIS-NPDES are databases that automate entering, updating, and retrieving discharge monitoring and permit data.

Dischargers submit discharge monitoring data to their permitting authority using discharge monitoring report (DMR) forms. The permitting authority then enters these data into PCS or ICIS-NPDES and checks whether the discharger is in compliance with the NPDES permit requirements. Facilities report pollutant discharge monitoring data in their DMR as mass-based quantities (e.g., pounds per day) and/or concentrations (e.g., mg/L); however, discharges are reported using a wide variety of units.

Permit data include NPDES permit limits for water quality parameters (e.g., dissolved oxygen and temperature), specific chemicals (e.g., phenol), bulk parameters (e.g., biochemical oxygen demand), and flow. The permitting authority enters these data into PCS or ICIS-NPDES. PCS and ICIS-NPDES also include information on the facility’s permit requirements, such as monitoring frequency.

  • PCS and ICIS-NPDES are national in scope, including data from all 50 states and 21 U.S. territories and tribes;
  • PCS and ICIS-NPDES contain discharge data that facilities determine through effluent chemical analyses and metered flow; and
  • PCS and ICIS-NPDES collectively include information for facilities in all point source categories that discharge directly to receiving streams.

The tool also includes wastewater pollutant discharge data from EPA’s Toxics Release Inventory (TRI). Data is available for the years 2007 through 2010. 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 – “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. See the Basics of TRI Reporting and Factors to Consider When Using TRI Data (PDF) (29 pp, 192K) for more information.

Other data sources used by the Loading Tool include:

  • Watershed Assessment Tracking and Environmental ResultS (WATERS) Web services for retrieving information about receiving waterbodies. WATERS derives some its data from EPA’s Assessment, TMDL Tracking and ImplementatioN System (ATTAINS) database, USGS Geographic Names Information System (GNIS), and the USGS National Hydrography Dataset (NHD);
  • 2008 Clean Watershed Needs Survey (CWNS) for providing information about treatment technologies in place at municipal wastewater treatment plants (a.k.a. Publicly-Owned Treatment Plants or POTWs);
  • EPA’s Facility Registry System (FRS) for providing facility location information and linking PCS and ICIS-NPDES facilities to other EPA programs, such as the Toxics Release Inventory (TRI);
  • EPA’s Substance Registry Services (SRS), which is the Agency’s central system for information about substances that are tracked or regulated by EPA or other sources. It is the authoritative resource for basic information about chemicals, biological organisms, and other substances of interest to EPA and its state and tribal partners; and
  • EPA’s STORET (short for STOrage and RETrieval) Data Warehouse, which is a repository for water quality, biological, and physical data.

Read about the Loading Tool data limitations

Top of Page

About the Data Glossary Error Correction Contact Us

Jump to main content.