Discharge Monitoring Report (DMR) Pollutant Loading Tool

Facility Universe

You should understand that while the Loading Tool includes discharges for more than 44,000 facilities, it is not a complete inventory of all discharges permitted under the Clean Water Act.

Although the Clean Water Act requires all point source dischargers to obtain a NPDES permit and monitor their wastewater, not all facility, permit, or discharge monitoring datas are uploaded into PCS and ICIS-NPDES. EPA places greater priority on major facilities, and requires authorized states to provide more information about the compliance status of these dischargers. Specifically, EPA policy requires the permitting authority to enter facility, permit, and DMR information from “major” dischargers into either PCS or ICIS-NPDES. EPA policy requires a more limited set of data be shared with EPA through data entry into PCS or ICIS-NPDES (PDF) (14 pp, 4.6MB) for “non-major” (or “minor”) facilities. Many authorized states also transmit facility, permit, and DMR data for non-major dischargers to the PCS or ICIS-NPDES databases. The map and links below detail the amount of DMR data that the states share with EPA’s PCS or ICIS-NPDES databases. These data come from EPA’s State Review Framework, which allows EPA to identify recommendations for improvement to ensure fair and consistent enforcement and compliance programs across the states. There are also differences between the states on sharing facility level data with EPA’s PCS or ICIS-NPDES databases for general permit covered facilities (e.g., oil and gas extraction facilities, construction stormwater sites). EPA and states issue general permits to increase the efficiency of the permit program as multiple similar facilities can be regulated under one permit.

• View more information about data completeness in the Loading Tool.
• Download state statistics and loadings for 2010
• Download state statistics and loadings for 2009
• Download state statistics and loadings for 2008
• Download state statistics and loadings for 2007

The Loading Tool contains information for industrial and municipal point source dischargers. Other types of Clean Water Act releases that are not available in the Loading Tool include:

• Wastewater releases from industrial facilities that are connected to a publicly-owned treatment works (POTW) sewerage system, regulated through the CWA Pretreatment Program;
• Biosolids monitoring data, regulated through the CWA Biosolids Program;
• Discharges related to wet-weather events, such as stormwater from municipal separate storm sewer systems (MS4s), stormwater from industrial facilities, discharges from construction activities, combined sewer overflows, sanitary sewer overflows, and concentrated animal feeding operations (CAFOs).

Although the Clean Water Act requires all point source dischargers to obtain a NPDES permit and monitor their wastewater, not all discharges are uploaded into PCS and ICIS-NPDES. EPA places greater priority on major facilities, and requires authorized states to provide more information about the compliance status of these dischargers. Specifically, EPA policy requires the permitting authority to enter DMR information from “major dischargers” into either PCS or ICIS-NPDES. Many authorized states also transmit DMR data for “minor dischargers” to the PCS or ICIS-NPDES databases.

Pollutant Universe

The Loading Tool includes approximately 1,000 pollutant parameters including specific chemicals (e.g., phenol), bulk parameters (e.g., biochemical oxygen demand), temperature, and wastewater flow. However, these pollutants do not account for all pollutants discharged to U.S. waters.

• PCS and ICIS-NPDES only include information about discharges of pollutants that a facility is required by permit to monitor; facilities are not required to monitor or report all pollutants they actually discharge.
• Discharge data are entered into PCS and ICIS-NPDES using a variety of measurement units. The Loading Tool can only calculate mass discharges for pollutants that are measured either as mass quantities or concentrations. Therefore some pollutants, such as toxicity parameters measured as percent, are excluded from the Loading Tool. Further, the Loading Tool cannot calculate a load for concentration measurements if a wastewater flow measurement is not provided.

Additionally, EPA policy requirement requires a more limited set of facility, permit and DMR data be shared with EPA through data entry into PCS or ICIS-NPDES for non-major facilities. Data sharing for these non-major facilities varies across the different state NPDES permit programs. Consequently, the Loading Tool will not identify all non-major facilities if you limit a search to a particular pollutant. The Loading Tool uses permit data to count facilities when the user searches on a particular pollutant.

Matching Facilities to Watersheds

The Loading Tool matches facilities to receiving watersheds based on a facility’s latitude and longitude coordinates and watershed spatial data in the Natural Resources Conservation Service’s Watershed Boundary Dataset (view the NRCS website). The Loading Tool cannot establish a match between a facility and a watershed if either:

• The facility does not have latitude or longitude coordinates; or
• There are no spatial data for the receiving watershed.

The Loading Tool uses names from the USGS Geographic Names Information System (GNIS). The GNIS is closely integrated with the National Hydrography Dataset (NHD), which makes these data more useful for plotting on maps and for watershed modeling and other research. Not all waterbodies receiving wastewater discharges have names in the GNIS and the not all names in the GNIS match the names that facilities provide in their NPDES permit application.

Data Quality

DMR data may be entered into the PCS or ICIS-NPDES database manually, which can lead to data-entry errors.

Intermittent Dischargers

Some facilities have intermittent discharges and may have one or more outfalls that don’t discharge for one or more months. Both PCS and ICIS-NPDES have ways of identifying when there is no discharge at a particular outfall for a monitoring period. However, states do not all use the same method and codes for identifying these intermittent dischargers (e.g., ICIS-NPDES has three codes for reporting the Duration of Discharge: 50037, 82517, and 81381). Consequently, the tool may overestimate pollutant discharges for intermittent dischargers that only discharge in emergency situations (i.e., facilities with unscheduled limit sets). EPA will work with states to improve pollutant discharge calculations for these intermittent dischargers.

Facility Universe

TRI reporting is limited to industrial facilities (i.e., POTWs do not report to TRI) and not all industry sectors report to TRI. Additionally, small establishments (less than 10 employees) are not required to report, nor are facilities that don't meet the reporting thresholds. Thus, facilities reporting to TRI may be a subset of an industry. See the Basics of TRI Reporting and Factors to Consider When Using TRI Data (PDF) (29 pp, 192K) for more information.

Pollutant Universe

TRI reporting focuses on toxic pollutant discharges and does not include common wastewater pollutants like Total Suspended Solids and Biochemical Oxygen Demand, which can be important factors when assessing the potential impact to surface waters. Additionally, the TRI Program doesn’t require additional monitoring, so reported releases are often, in part, based on estimates, not measurements, and, due to TRI guidance, may differ greatly from DMR data, especially at facilities with large wastewater flows. Finally, certain chemicals (polycyclic aromatic compounds [PACs], dioxin and dioxin-like compounds, metal compounds) are reported as a class, not as individual compounds. Because the individual compounds in most classes have widely varying toxic effects, the potential toxicity of chemical releases can be inaccurately estimated.

Matching Facilities to Watersheds or to POTWs

TRI reporting does require facilities to report the names of the surface waterbodies and POTWs that receive their wastewater discharges. See Sections 5.3 and 6.1 in TRI Form R. However, these reported names are not standardized or indexed to the NHD or EPA’s Federal Registry System (FRS). Consequently, it is not currently possible to accurately match TRI reporters to the receiving waterbody or POTW that is receiving their wastewater discharges.

Data Quality

The TRI Program conducts a number of activities every year to ensure the quality of TRI data reported to EPA. These activities range from providing extensive reporting guidance, intelligent reporting software, and training to facilities prior to the reporting deadline as well as data validation and analysis after the data are received. See the TRI Data Quality Program Information page for more information on these activities.