Action towards Limiting Nitrogen and Phosphorus Loads from NPDES-Permitted Facilities
About this indicator
Discharges from industrial facilities, especially wastewater treatment facilities, with little to no treatment for nitrogen and phosphorus are a significant source of these nutrients to surface waters throughout the country. Setting permit limits and treating the wastewater to meet these limits can substantially reduce nitrogen and phosphorus loading from these facilities, protecting local and downstream water quality. The data in this indicator are for major (≥1 million gallons/day (MGD)) and minor (<1 MGD) industrial and publically-owned treatment facilities with individual or general National Pollutant Discharge Elimination System (NPDES) permits that, based on their operation, permit limits, monitoring requirements, or discharges, are likely to be discharging nitrogen and phosphorus. Listed are the percent of such facilities that have permit limits (which include monitoring requirements), or monitoring requirements only, for total nitrogen and/or total phosphorus.
State progress towards implementing total nitrogen (TN) and total phosphorus (TP) National Pollutant Discharge Elimination System (NPDES) permit limits, or monitoring requirements only, for major and minor facilities likely to discharge nitrogen (N) and phosphorus (P). Data are from the 2010-2011 review period.
| Major and Minor dischargers | Major dischargers only | ||||||||||
| State | # of facilities likely to discharge N&P | % with TN limits | % with TP limits | % with TN monitoring only | % with TP monitoring only | # of facilities likely to discharge N&P | % with TN limits | % with TP limits | % with TN monitoring only | % with TP monitoring only | |
|---|---|---|---|---|---|---|---|---|---|---|---|
| Alabama | 2,635 | 0% | 17% | 15% | 33% | 185 | 2% | 7% | 5% | 81% | |
| Alaska | 5,804 | 0% | 0% | 0% | 0% | 61 | 0% | 0% | 0% | 2% | |
| Arizona | 162 | 2% | 4% | 2% | 33% | 70 | 4% | 3% | 1% | 71% | |
| Arkansas | 1,728 | 1% | 2% | 0% | 6% | 164 | 0% | 8% | 1% | 18% | |
| California | 1,311 | 0% | 0% | 3% | 4% | 229 | 2% | 2% | 17% | 21% | |
| Colorado | 1,442 | 0% | 3% | 0% | 4% | 108 | 1% | 9% | 0% | 2% | |
| Connecticut | 180 | 5% | 6% | 6% | 9% | 103 | 4% | 6% | 8% | 8% | |
| Delaware | 41 | 22% | 32% | 10% | 12% | 19 | 26% | 32% | 11% | 11% | |
| Florida | 1,463 | 9% | 9% | 12% | 11% | 174 | 43% | 47% | 41% | 33% | |
| Georgia | 1,202 | 0% | 8% | 0% | 9% | 187 | 1% | 28% | 1% | 38% | |
| Hawaii | 168 | 4% | 4% | 13% | 13% | 19 | 5% | 5% | 84% | 79% | |
| Idaho | 689 | 0% | 12% | 0% | 8% | 55 | 0% | 20% | 0% | 51% | |
| Illinois | 2,576 | 0% | 2% | 2% | 2% | 240 | 0% | 12% | 17% | 15% | |
| Indiana | 2,274 | 0% | 6% | 0% | 4% | 176 | 0% | 22% | 0% | 13% | |
| Iowa | 1,285 | 2% | 0% | 0% | 0% | 113 | 2% | 0% | 0% | 0% | |
| Kansas | 892 | 0% | 0% | 5% | 6% | 53 | 4% | 0% | 70% | 79% | |
| Kentucky | 3,104 | 0% | 2% | 6% | 8% | 117 | 0% | 16% | 38% | 56% | |
| Louisiana | 5,637 | 0% | 0% | 0% | 1% | 300 | 1% | 1% | 3% | 10% | |
| Maine | 217 | 0% | 10% | 0% | 9% | 77 | 0% | 8% | 0% | 14% | |
| Maryland | 1,374 | 7% | 8% | 10% | 6% | 86 | 33% | 65% | 47% | 13% | |
| Massachusetts | 496 | 1% | 17% | 6% | 6% | 110 | 4% | 51% | 19% | 12% | |
| Michigan | 1,399 | 0% | 23% | 0% | 15% | 147 | 0% | 82% | 1% | 6% | |
| Minnesota | 794 | 0% | 6% | 0% | 7% | 89 | 0% | 46% | 1% | 51% | |
| Mississippi | 875 | 2% | 2% | 13% | 14% | 88 | 8% | 8% | 55% | 57% | |
| Missouri | 3,234 | 0% | 2% | 1% | 3% | 151 | 1% | 5% | 5% | 10% | |
| Montana | 627 | 14% | 12% | 30% | 35% | 33 | 15% | 24% | 48% | 55% | |
| Nebraska | 638 | 2% | 0% | 1% | 4% | 51 | 6% | 0% | 4% | 6% | |
| Nevada | 233 | 2% | 2% | 0% | 3% | 12 | 33% | 25% | 8% | 58% | |
| New Hampshire | 160 | 0% | 9% | 4% | 13% | 46 | 0% | 22% | 7% | 20% | |
| New Jersey | 1,139 | 0% | 9% | 0% | 7% | 130 | 0% | 25% | 0% | 24% | |
| New Mexico | 426 | 0% | 1% | 1% | 2% | 33 | 3% | 12% | 6% | 3% | |
| New York | 2,412 | 17% | 15% | 2% | 7% | 313 | 2% | 24% | 9% | 23% | |
| North Carolina | 971 | 1% | 8% | 0% | 0% | 195 | 4% | 21% | 1% | 1% | |
| North Dakota | 89 | 0% | 1% | 0% | 3% | 25 | 0% | 4% | 0% | 12% | |
| Ohio | 2,894 | 0% | 7% | 0% | 21% | 279 | 0% | 36% | 1% | 43% | |
| Oklahoma | 783 | 0% | 2% | 0% | 1% | 88 | 1% | 7% | 1% | 3% | |
| Oregon | 292 | 0% | 0% | 0% | 2% | 67 | 0% | 1% | 0% | 7% | |
| Pennsylvania | 6,826 | 0% | 2% | 3% | 2% | 381 | 1% | 28% | 29% | 27% | |
| Rhode Island | 207 | 5% | 5% | 11% | 8% | 23 | 43% | 30% | 57% | 26% | |
| South Carolina | 405 | 0% | 8% | 22% | 31% | 147 | 0% | 11% | 32% | 29% | |
| South Dakota | 600 | 0% | 0% | 0% | 3% | 29 | 0% | 0% | 0% | 17% | |
| Tennessee | 903 | 2% | 2% | 11% | 13% | 152 | 7% | 9% | 45% | 49% | |
| Texas | 4,733 | 0% | 1% | 0% | 1% | 569 | 0% | 4% | 1% | 3% | |
| Utah | 588 | 0% | 1% | 0% | 5% | 34 | 0% | 6% | 3% | 26% | |
| Vermont | 112 | 1% | 13% | 3% | 1% | 31 | 0% | 42% | 6% | 0% | |
| Virginia | 752 | 0% | 5% | 5% | 3% | 134 | 1% | 26% | 26% | 16% | |
| Washington | 343 | 0% | 0% | 0% | 1% | 49 | 0% | 0% | 0% | 0% | |
| West Virginia | 451 | 0% | 0% | 58% | 58% | 94 | 1% | 1% | 79% | 79% | |
| Wisconsin | 821 | 0% | 14% | 0% | 1% | 122 | 0% | 93% | 0% | 2% | |
| Wyoming | 195 | 0% | 0% | 0% | 1% | 21 | 0% | 0% | 0% | 5% | |
Note - Using information entered into EPA's ICIS or PCS databases, a facility was considered likely to discharge N and P based on 1) whether or not it is a Publically Owned Treatment Work (POTW), 2) its SIC code or 3) whether or not it has permit limits, monitoring requirements, or discharge data for N and P. Only limits and monitoring for TN and TP were included - not for other N/P species.
Source: The EPA's Integrated Compliance Information System (ICIS) and the Permit Compliance System (PCS) databases (data from 2010-2011 review period).
Download the Limiting Loads data table (excel) (2 pp, 19 K)
Source of data
1. U.S. EPA. Integrated Compliance Information System (ICIS) and Permit Compliance System (PCS) databases, from the 2010-2011 review period.
Data source information
This indicator provides National Pollutant Discharge Elimination System (NPDES) permit information from EPA’s Integrated Compliance Information System (ICIS-NPDES) and the Permit Compliance System (PCS) databases, as obtained by EPA staff from the data warehouses ICIS-COPY and Envirofacts, respectively. Data are from the 2010-2011 review period. Users can obtain data from these warehouses via the Discharge Monitoring Report Pollutant Loading Tool.
Facilities likely to discharge nitrogen and phosphorus were identified based on one of the following:
- The facility’s identification as a Publicly-Owned Treatment Work (POTW) in ICIS-NPDES or PCS.
- For non-POTWs, whether the facility’s Standard Industrial Classification (SIC) code has a typical pollutant concentration (TPC, assigned by EPA based on discharge monitoring report data from ICIS-NPDES or PCS) value for any of the following: ammonia, total Kjeldahl nitrogen, nitrate, total organic nitrogen, total nitrogen or total phosphorus.
- Whether the facility has limits, monitoring requirements, and/or discharge data for nitrogen and/or phosphorus in ICIS-NPDES or PCS.
What to consider when using these data
This indicator does not include information for facilities with permit limits and monitoring requirements for other nitrogen species (i.e., nitrate, nitrite, ammonia, total inorganic nitrogen, total Kjeldahl nitrogen, dissolved organic nitrogen) or phosphorus species (i.e., phosphate). The data presented in this indicator are entered by permitting authorities into ICIS-NPDES or PCS either electronically or manually, and filing manually may lead to data-entry errors. Permitting authorities may not enter monitoring requirements or permit limits for minor facilities, and furthermore, if a permitting authority is delayed in entering permit facility and discharge information into ICIS-NPDES or PCS, that information would not be reflected in this dataset.
References and links to other data sources
1. Chesapeake Bay Program. 2004. NPDES Permitting Approach for Discharges of Nutrients in the Chesapeake Bay Watershed.
2. U.S. EPA. NPDES program: Municipalities and Wastewater Treatment Plants.
3. U.S. EPA. Discharge Monitoring Report Pollutant Loading Tool.
4. U.S. EPA. Envirofacts.
5. U.S. EPA. ECHO: Enforcement and Compliance History Online.
6. U.S. Department of the Interior. National Atlas: NPDES wastewater treatment plant mapping.