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ICIS-NPDES Limit Summary and Data Element Dictionary
The Enforcement and Compliance History Online (ECHO) system provides a compendium of the effluent parametric limits that are identified in the NPDES permits issued to entities (municipal, federal, and commercial facilities) that discharge pollutants into the navigable waters of the United States. These limits identify what pollutants can be discharged and how much of each pollutant can be discharged as well as certain water conditions such as pH and dissolved oxygen content that must be maintained at the locations where the discharges occur. At EPA, the official source of NPDES limit data is stored in the Office of Enforcement Compliance Assurance, Integrated Compliance Information System (ICIS) where it is extracted by ECHO.
Limit File Description
The Limit download data file is comprised of limit information that was in effect starting from FY 2009 until the present day. In the zip file, npdes_limits_fy2009plus.zip, there is one CSV file named, NPDES_LIMITS_FY2009PLUS.csv. The zip file is updated each week, typically over the weekend.
The data contained in the download file is comprised of selected data columns from the following ICIS tables:
IDEA_ICIS | ICIS_LIMIT |
IDEA_ICIS | ICIS_LIMIT_SET |
IDEA_ICIS | ICIS_LIMIT_SET_SCHEDULE |
IDEA_ICIS | ICIS_LIMIT_SET_STATUS |
IDEA_ICIS | ICIS_LIMIT_VALUE |
IDEA_ICIS | ICIS_PERMIT |
IDEA_ICIS | ICIS_PERM_FEATURE |
ICIS-NPDES Data Elements
NPDES DMR (NPDES_DMR_FYxxxx.csv)
Element Name | Data Type | Length |
---|---|---|
ACTIVITY_ID | Number | 22 |
EXTERNAL_PERMIT_NMBR | VarChar2 | 9 |
VERSION_NMBR | Number | 22 |
PERM_FEATURE_ID | Number | 22 |
PERM_FEATURE_NMBR | VarChar2 | 4 |
PERM_FEATURE_TYPE_CODE | VarChar2 | 3 |
LIMIT_SET_ID | Number | 22 |
LIMIT_SET_SCHEDULE_ID | Number | 22 |
LIMIT_ID | Number | 22 |
LIMIT_BEGIN_DATE | Date | 7 |
LIMIT_END_DATE | Date | 7 |
NMBR_OF_SUBMISSION | Number | 22 |
PARAMETER_CODE | VarChar2 | 5 |
PARAMETER_DESC | VarChar2 | 100 |
MONITORING_LOCATION_CODE | VarChar2 | 3 |
STAY_TYPE_CODE | VarChar2 | 1 |
LIMIT_VALUE_ID | Number | 22 |
LIMIT_VALUE_TYPE_CODE | VarChar2 | 3 |
LIMIT_VALUE_NMBR | Number | 22 |
LIMIT_UNIT_CODE | VarChar2 | 2 |
LIMIT_UNIT_DESC | VarChar2 | 13 |
STANDARD_UNIT_CODE | VarChar2 | 2 |
STANDARD_UNIT_DESC | VarChar2 | 13 |
LIMIT_VALUE_STANDARD_UNITS | Number | 22 |
STATISTICAL_BASE_CODE | VarChar2 | 3 |
STATISTICAL_BASE_TYPE_CODE | VarChar2 | 3 |
LIMIT_VALUE_QUALIFIER_CODE | VarChar2 | 3 |
STAY_VALUE_NMBR | Number | 22 |
Limit Data Element Definitions
The following is a list of the data elements and ICIS-derived elements that appear in the NPDES DMR download.
ACTIVITY_ID - The unique identifier for an activity performed at or related to a particular site.
EXTERNAL_PERMIT_NMBR - The unique identifier for a Permit.
LIMIT_END_DATE - The date on which a limit stops being in effect for a particular parameter in a limit set.
LIMIT_ID - The unique identifier for a limit parameter record.
LIMIT_BEGIN_DATE - The date on which a limit starts being in effect for a particular parameter in a limit set.
LIMIT_SET_ID - The system-generated unique identifier for a limit set.
LIMIT_SET_SCHEDULE_ID - The system-generated unique identifier of the Limit Set Schedule.
LIMIT_UNIT_CODE - The code representing the unit of measure applicable to quantity or concentration limits and measurements as entered by the user.
LIMIT_UNIT_DESC - The short description of the unit of measure applicable to limit or DMR values.
LIMIT_VALUE_ID - The system-generated unique identifier for the Limit Value.
LIMIT_VALUE_NMBR - The actual limit value number from the Permit or Enforcement Action Final Order.
LIMIT_VALUE_QUALIFIER_CODE - The unique code identifying the limit value operator (e.g., <, T, >, E, =).
LIMIT_VALUE_STANDARD_UNITS - The limit value expressed in standard units as calculated by the system.
LIMIT_VALUE_TYPE_CODE - The indication of the limit value type (e.g., Quantity 1, Concentration 2).
MONITORING_LOCATION_CODE - The code that the monitoring location at which the monitoring requirement (and effluent limit if limited) applies. One parameter may have several monitoring location requirements pertaining to the same permitted feature. Valid code values are:
Code | Description |
---|---|
0 | Intake |
1 | Effluent Gross |
2 | Effluent Net |
3 | Intake Public Water |
4 | Pretreatment, Process Complete |
5 | Upstream Monitoring |
6 | Downstream Monitoring |
7 | Intake from Stream |
8 | Other Treatment, Process Complete |
9 | Phosphate Removal, Process Complete |
A | Disinfection, Process Complete |
AP | Alternate Process |
B | Prior to Disinfection |
C | Nitrogen, Removal Complete |
D | Tertiary/Advanced Process Complete |
E | Secondary/Biological Process Complete |
EG | Effluent Gross |
F | Primary/Preliminary Process Complete |
G | Raw Sewage Influent |
H | During Manufacturing |
I | Intake from Well |
IN | Allowed Increase |
J | Intermediate Treatment, Process Complete |
K | Percent Removal |
L | Digestor |
N | In Aeration Unit |
O | See Comments |
P | See Comments |
Q | See Comments |
R | See Comments |
RS | Beneficial Reuse |
RW | Receiving Water |
S | See Comments |
SC | See Comments |
SL | Sludge |
T | See Comments |
U | See Comments |
V | See Comments |
W | See Comments |
X | End of Chlorine Contact Chamber |
Z | Instream Monitoring |
Y | Effluent Gross (Supplementary) |
GW | Groundwater |
II | Industrial Influent |
IM | Internal Monitoring Point |
PI | Prior to Irrigation |
PR | Prior to Reuse |
LA | Land Application Soil |
NMBR_OF_SUBMISSION - The attribute stores the number of months for submitting the DMRs for the limit set (e.g., monthly = 1, semi-annually = 6, quarterly = 3). This data element will be blank for Unscheduled Limit Sets.
PARAMETER_CODE - The unique code identifying the parameter being limited and/or monitored.
PARAMETER_DESC - The description of the parameter.
PERM_FEATURE_ID - The unique system identifier of a permitted feature.
PERM_FEATURE_NMBR - The identifier assigned for each location at which permit conditions are being applied.
PERM_FEATURE_TYPE_CODE - The code indicating the type of permitted feature (e.g., External Outfall, Sum). Valid code values are:
Code | Description |
---|---|
ARW | Receiving Water (Ambient) |
CDS | Co-disposal Site |
DOF | Discharge to Offsite Facility |
EXO | External Outfall |
INC | Incinerator |
INF | Influent Structure |
INO | Internal Outfall |
INS | Intake Structure |
LAS | Land Application Site |
MOD | MODU |
OTR | Other |
PLA | Platform |
SDS | Surface Disposal Site |
SUB | Subsea |
SUM | Sum |
WEL | Monitoring Well |
STANDARD_UNIT_CODE - The code representing the standard unit of measure applicable to quantity or concentration limits and measurements as entered by the user.
STANDARD_UNIT_DESC - The short description of the standard unit of measure applicable to limit or DMR values.
STATISTICAL_BASE_CODE - The code representing the unit of measure applicable to the limit and DMR values entered by the user (e.g., 30-day average, daily maximum). Valid code values are:
Type | Code | Long Description |
---|---|---|
AVG | 1A | 1 Day Geometric |
AVG | 1C | 12 Day Average |
AVG | 1D | 12 Month Average |
AVG | 1E | 12 Month Daily Water Flow |
AVG | 1F | 120 Day Average |
AVG | 1G | 180 Day Arithmetic Mean |
AVG | 1H | 1 Day Average |
AVG | 1I | 1 Hour Average |
AVG | 3A | 30 Day Geometric Mean |
AVG | 3B | 30 Day Arithmetic |
AVG | 3C | 30 Day Average |
AVG | 3D | 30 Day Geometric |
AVG | 3F | 30 Day Arithmetic Mean |
AVG | 3G | 30 Day Median |
AVG | 3H | 30 Day Average Geometric |
AVG | 3I | 3 Hour Average |
AVG | 4A | 4 Day Average |
AVG | 4D | 4 Hour Average |
AVG | 5B | 5 Day Average |
AVG | 5Y | 5 Year Average |
AVG | 6A | 6 Month Median |
AVG | 6B | 6 Hour Mean |
AVG | 6C | 6 Hour Geometric Mean |
AVG | 6D | 6 Month Average |
AVG | 6E | 6 Hour Average |
AVG | 6F | 6 Hour Geometric |
AVG | 7A | 7 Day Average |
AVG | 7B | 7 Day Geometric |
AVG | 7C | 7 Day Median |
AVG | 7F | 7 Day Arithmetic |
AVG | 7G | 7 Day Arithmetic Mean |
AVG | 7I | 7-Day Average Geometric |
AVG | 9B | 90 Day Average |
AVG | 9D | 96 Hour |
AVG | A1 | Average (Data Migration) |
AVG | AB | Annual Average |
AVG | AE | Arithmetic Mean |
AVG | AF | Average |
AVG | AG | Average Below Detectable |
AVG | AGM | Annual Geometric Mean |
AVG | AH | Average Value |
AVG | AN | Annual Median |
AVG | CA | Allowed Concentration |
AVG | DA | Daily Geometric Average |
AVG | DB | Daily Average |
AVG | DF | Daily Median |
AVG | DG | Discharge Per Day Average |
AVG | DH | Discharge per Day Geometric |
AVG | DM | Daily Geometric |
AVG | DP | 14 Day Average |
AVG | G5 | 5 Day Geometric Mean |
AVG | GA | Geometric Mean |
AVG | HA | High 7 Day Average |
AVG | HB | High Weekly Average |
AVG | LA | Logarithmic Mean |
AVG | LB | Logarithmic Monthly Median |
AVG | M3 | Monthly Median |
AVG | M4 | Monthly Average Geometric |
AVG | MC | Mean |
AVG | MD | Median |
AVG | MK | Monthly Average |
AVG | ML | Monthly Geometric |
AVG | MM | Monthly Geometric Mean |
AVG | NA | Non-Specific Average |
AVG | QA | Quarterly Average |
AVG | QR | Quarterly Rolling Average |
AVG | RA | Rolling Average |
AVG | RB | Reported Average |
AVG | RE | Indiv 12 Mo Rolling Ave |
AVG | RF | Aggregate 12 Mo Rolling Avg |
AVG | RM | Aggregate 12 Mo Rolling Median |
AVG | SC | Semi-Annual Average |
AVG | SD | Single Sample Geometric |
AVG | WA | Weekly Average |
AVG | WB | Weekly Geometric |
AVG | WE | Weekly Average Geometric |
AVG | WK | Weekly Geometric Mean |
AVG | WL | Well Average |
MAX | 1B | 10% of Samples |
MAX | 2A | 20% of Samples |
MAX | 2P | 2 Hour Peak |
MAX | 3E | 30 Day Maximum |
MAX | 4B | 4 Day Maximum |
MAX | 4C | 48 Hour Maximum |
MAX | 5A | 50th Percentile |
MAX | 7E | 7 Day Maximum |
MAX | 7H | 75th Percentile |
MAX | 7J | 70th Percentile |
MAX | 8A | 80th Percentile |
MAX | 95P | 95th Percentile |
MAX | 9A | 90th Percentile |
MAX | 9C | 90% of Samples |
MAX | AC | Annual Maximum |
MAX | AX | Annual Average Maximum |
MAX | DD | Daily Maximum |
MAX | DI | Discharge Per Day Maximum |
MAX | EX | Seasonal Maximum |
MAX | GX | Maximum Monthly Geometric Mean |
MAX | HX | Hourly Avg Maximum |
MAX | IA | Instantaneous Maximum |
MAX | M0 | Maximum Value |
MAX | M1 | Maximum 30 Day Average |
MAX | M2 | Maximum Monthly Average |
MAX | M6 | Maximum (Data Migration) |
MAX | MA | Maximum Bdl |
MAX | MB | Maximum |
MAX | MN | Monthly Maximum |
MAX | MQ | Maximum Daily Average |
MAX | MR | Maximum Hourly Rate |
MAX | MS | Maximum Weekly Average |
MAX | MT | Maximum 7 Day Average |
MAX | MU | Maximum 7 Day Geometric |
MAX | MV | Maximum 7 Day Geo. Average |
MAX | MW | Maximum Single Sample |
MAX | MX | Monthly Geometric Maximum |
MAX | NB | Non-Specific Maximum |
MAX | QB | Quarterly Maximum |
MAX | RD | Rpt Allowed/Rpt Actual |
MAX | SA | Single Sample |
MAX | SB | Single Mv Conc. Sample |
MAX | SE | Single Reading |
MAX | SF | Successful Readings |
MAX | SG | Single Grab |
MAX | SX | Semi-Annual Maximum |
MAX | VA | Value |
MAX | WC | Weekly Maximum |
MAX | X1 | Positive Results |
MAX | XA | >Background |
MIN | 1J | 1 Day Minimum |
MIN | 2E | 24 Hour Minimum |
MIN | 4E | 48 Hour Minimum |
MIN | 7D | 7 Day Minimum |
MIN | AM | Annual Average Minimum |
MIN | BA | Median (Minimum) |
MIN | BB | Average (Minimum) |
MIN | BC | 90Th Percentile (Minimum) |
MIN | BD | 70Th Percentile (Minimum) |
MIN | BE | 50Th Percentile (Minimum) |
MIN | DC | Daily Minimum |
MIN | DE | Daily Average Minimum |
MIN | DJ | Discharge Per Day Minimum |
MIN | DL | Daily Geometric Minimum |
MIN | HM | Hourly Avg Minimum |
MIN | IB | Instantaneous Minimum |
MIN | IC | Instantaneous Min. Geom |
MIN | M5 | Minimum (Data Migration) |
MIN | ME | Minimum |
MIN | MF | Minimum Percent Removal |
MIN | MG | Minimum Weekly Average |
MIN | MH | Minimum 7 Day Average |
MIN | MI | Minimum 7 Day Geo. Average |
MIN | MJ | Monthly Average Minimum |
MIN | MO | Monthly Minimum |
MIN | MZ | Minimum Value |
MIN | NS | Minimum Single Sample |
MIN | QC | Quarterly Minimum |
MIN | RC | Reported Minimum |
MIN | SM | Semi-Annual Minimum |
MIN | TM | Monthly Total Minimum |
MIN | WD | Weekly Minimum |
MIN | YM | Yearly Minimum |
TTL | AA | Allowed Load |
TTL | AD | Annual Total |
TTL | AL | Annual Mass Loading |
TTL | BF | Cumulative Total |
TTL | DK | Discharge Per Day Total |
TTL | DN | Discharged |
TTL | ET | Event Total |
TTL | LE | Pounds Per Event |
TTL | MP | Monthly Total |
TTL | MY | Monthly Loading |
TTL | QT | Quarterly Total |
TTL | ST | Semi-Annual Total |
TTL | TA | Total Amount Applied |
TTL | TB | Total |
TTL | TC | Season To Date Total |
TTL | WT | Weekly Total |
TTL | YA | Year-To-Date Total |
STATISTICAL_BASE_TYPE_CODE - The code indicating whether the statistical base code is a minimum, average, or maximum for purposes of calculating compliance against the limit value.
STAY_TYPE_CODE - The unique identifier of the type of stay applied to a limit (e.g., X, Y, Z), which indicates whether the limits do not appear on the DMR at all, are treated as monitor only, or have a stay value in effect during the period of the stay.
STAY_VALUE_NMBR - The numeric limit value imposed during the period of the stay for the limit; if entered, during the stay period, the system will use this limit value for calculating compliance rather than the actual limit value.
VERSION_NMBR - The version of the permit when a modification or reissuance is applied to the permit.