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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).

Frequently Asked Questions and Answers

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Background & General Questions

What is the Discharge Monitoring Report (DMR) Pollutant Loading Tool?

What is the National Pollutant Discharge Elimination System (NPDES)?

What are Discharge Monitoring Reports (DMRs)?

What is the frequency of these DMR submissions?

Are permitted facilities required to submit DMRs to their permitting authority?

What laboratory analytical methods do NPDES permitted facilities use to identify and quantify the pollutant concentrations in their discharge? Is this information in the Loading Tool?

How does the NPDES permit program relate to the Permit Compliance System (PCS) and Integrated Compliance Information System - National Pollutant Discharge Elimination System (ICIS-NPDES)?

Why did EPA use two databases to manage DMR data?

When will all authorized states switch from using PCS to the ICIS-NPDES database?

How do authorized states submit DMRs into PCS or ICIS-NPDES?

How does the “major” and “non-major” designation affect what discharge data I can view?

What are the data entry requirements for facility, permit, and DMR data differ between “major” and “non-major” facilities and general permit covered facilities?

What are authorized states and EPA doing to increase availability and public transparency of DMR data?

What types of data are included in the Loading Tool?

What types of data are NOT included in the Loading Tool?

Does the EZ Search (DMR) estimate pollutant loadings for facilities that do not have their DMR data in PCS or ICIS-NPDES?

Does the Loading Tool estimate pollutant loadings for non-point source pollution (e.g., agricultural areas)?

Does the EZ Search (DMR) estimate pollutant loadings for industrial facilities that discharge to publicly-owned treatment works (POTWs )?

How do EPA and state NPDES permit writers determine which pollutants should be monitored or controlled by effluent limits?

Has EPA used pollutant loads data previously?

I am a beginner user of discharge monitoring data, how can I use the Loading Tool?

I am an advanced user of discharge monitoring or TRI data, how can I use the Loading Tool?

What are the key search options in the DMR Pollutant Loading Tool?

How can I tell whether a facility has a limit for a pollutant, or is only required to do monitoring?

Why do some similar facilities have limits for certain chemicals, while other similar facilities do not have limits?

What if I cannot find a particular facility in the DMR Pollutant Loading Tool?

What if I need additional help?

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Technical Questions

How does the DMR Pollutant Loading Tool calculate pollutant loadings?

How does EPA take wastewater discharge flow and pollutant concentration data to calculate annual pollutant load discharges?

What web technologies support the Loading Tool?

How does the DMR Pollutant Loading Tool calculate pollutant loadings for intermittent pollutant discharges?

How does the DMR Pollutant Loading Tool calculate pollutant loadings for NPDES facilities in PCS or ICIS-NPDES when the frequency of their DMR is not monthly or if some of their monitoring results are not reported to PCS or ICIS-NPDES?

Why are the different types of NPDES permit effluent limits and monitoring requirements?

Why do NPDES permits sometimes require monthly average effluent limits and daily maximum effluent limits for the same pollutant at the same outfall at the same facility

Why are some numeric effluent limits and monitoring requirements expressed in units of quantity (e.g., pounds per day) or concentration (e.g., mg/L)?

Are NPDES dischargers required to report discharge monitoring data that are below the laboratory analytical method detection limits or quantitation limits?

How do PCS and ICIS-NPDES track pollutant concentration data that are below the laboratory analytical method detection limits or quantitation limits?

How does the EZ Search (DMR) calculate annual pollutant loads using pollutant concentration data that are below the laboratory analytical method detection limits or quantitation limits?

What is the relative difference in annual pollutant loadings between the method of setting all pollutant concentration data that are below the laboratory analytical method quantitation limit equal to zero versus the hybrid approach used by EZ Search (DMR)?

How does the EZ Search (DMR) differ from TRI estimates for pollutant concentration data that are below the laboratory analytical method detection limits or quantitation limits?

What options do I have with the Advanced Search to calculate annual pollutant loads using pollutant concentration data that are below the laboratory analytical method detection limits or quantitation limits?

How does the Loading Tool round its calculated pollutant discharges?

What is a Toxic-Weighted Pound Equivalent (TWPE)?

Can I download data from the DMR Pollutant Loading Tool?

How can I get access to the entire database supporting the Loading Tool?

How does PCS and ICIS-NPDES identify the industrial sector for a NPDES permitted facility?

Does the Loading Tool track information on water quality trading?

What chemicals are reported in the TRI program?

Why are the annual wastewater pollutant discharge estimates from EZ Search (DMR) and TRI Search sometimes different for the same pollutant at the same facility for the same year?

Does EPA enforce TRI reporting requirements?

Can you match the names of surface waterbodies and POTWs that receive TRI discharges to the USGS National Hydrography Dataset (NHD) or to EPA’s FRS?

How are Exceedance Counts different from Load Over Limit?

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Integration with Other Data Sources

Is any additional information available on pollutant discharge data?

Can I tell whether the facility is violating their limits?

Where can I find more information about specific enforcement cases taken by EPA under the Clean Water Act?

Is there a way to search the loadings data using existing ECHO searches?

Can I tell whether the discharges are related to water quality impairment?

Where can I find water quality information for a watershed of interest to me?

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Data Quality Questions and Data Release Schedule

How accurate is DMR Pollutant Loading Tool and what steps were taken to ensure accuracy?

How can I identify and notify EPA of possible DMR data errors?

How can I notify EPA of other (non-DMR) potential errors that I see on the Loading Tool?

How frequently will EPA update access to DMR data with the Loading Tool?

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