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National Summary of Impaired Waters and TMDL Information 

Impaired Waters Listed By State 

Description of this table

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Impaired 

Waters Listed 

by State 

Causes of 

Impairment for

303(d) Listed 

Waters 

Cumulative 

TMDLs by 

Pollutant 

Approved 

TMDLs by 

State 

Cumulative 

Number of 

TMDLs 

Status of 

Available Data 

Used in This 

Report 

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Information: 

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National Summary of

Impaired Waters and TMDL 

Information 

Depicted below are national summary tables and charts 

for available water quality data reported by the States to 

EPA under Section 305(b) and 303(d) of the Clean 

Water Act. 

This report displays the most current available reporting 

year data. 

Check the Status of Available Data for more information. 

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Assessment Databas

State Name Number of Waters on 303(d) List

Alabama 200

Alaska 32

American Samoa 42

Arizona 84

Arkansas 224

California 691

Colorado 198

Watershed Assessment, Tracking & Environmental ResultS

http://iaspub.epa.gov/waters10/attains_nation_cy.control?p_report_type=T

Last updated on Monday, May 24, 2010

National Summary of Impaired Waters and TMDL Information | WATERS | US EPA Page 1 of 9

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Connecticut 408

Delaware 101

District Of Columbia 27

Florida 827

Georgia 281

Guam 54

Hawaii 311

Idaho 1,057

Illinois 1,058

Indiana 1,836

Iowa 278

Kansas 1,333

Kentucky 1,089

Louisiana 250

Maine 206

Maryland 501

Massachusetts 837

Michigan 2,352

Minnesota 1,144

Mississippi 197

Missouri 204

Montana 677

N. Mariana Islands 71

Nebraska 177

Nevada 181

New Hampshire 1,089

New Jersey 745

New Mexico 187

New York 491

North Carolina 902

North Dakota 247

Ohio 267

Oklahoma 743

Oregon 1,397

Pennsylvania 6,957

Puerto Rico 166

Rhode Island 141

South Carolina 1,060

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http://iaspub.epa.gov/waters10/attains_nation_cy.control?p_report_type=T 5/24/2010
Total: 39,998 impaired waters 

Causes of Impairment for 303(d) Listed Waters 

Description of this table

South Dakota 168

Tennessee 900

Texas 651

Utah 118

Vermont 131

Virgin Islands 77

Virginia 2,534

Washington 2,419

West Virginia 981

Wisconsin 593

Wyoming 106

NOTE: Click on a cause of impairment (e.g. pathogens) to see the specific state-reported causes that 

are grouped to make up this category. Click on the "Number of Causes of Impairment Reported" to 

see a list of waters with that cause of impairment.

Cause of Impairment Group Name Number of Causes of Impairment Reported

Pathogens 10,761

Metals (other than Mercury) 7,503

Nutrients 6,847

Organic Enrichment/Oxygen Depletion 6,506

Sediment 6,293

Polychlorinated Biphenyls (PCBs) 6,177

Mercury 3,770

pH/Acidity/Caustic Conditions 3,712

Cause Unknown - Impaired Biota 3,320

Turbidity 3,055

Temperature 3,044

Pesticides 1,798

Salinity/Total Dissolved 

Solids/Chlorides/Sulfates 1,745

Cause Unknown 1,259

Noxious Aquatic Plants 981

Habitat Alterations 702

Dioxins 549

Algal Growth 549

Toxic Organics 459

356

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http://iaspub.epa.gov/waters10/attains_nation_cy.control?p_report_type=T 5/24/2010
Total: 70,947 Causes of Impairment 

National Cumulative TMDLs by Pollutant 

This chart includes TMDLs since October 1, 1995. 

Description of this table

Ammonia

Toxic Inorganics 352

Total Toxics 318

Other Cause 222

Oil and Grease 155

Taste, Color and Odor 115

Flow Alteration(s) 109

Trash 57

Fish Consumption Advisory 56

Biotoxins 53

Radiation 44

Chlorine 34

Nuisance Exotic Species 29

Cause Unknown - Fish Kills 12

Nuisance Native Species 5

NOTE: Click on the underlined "Pollutant Group" value to see a

detailed list of pollutants. Click on the underlined "Number of 

TMDLs" value to see a listing of those TMDLs for the pollutant 

Group.

Pollutant Group Number of TMDLs

Number of 

Causes of

Impairment

Addressed

Pathogens 7,931 8,172

Metals (other than 

Mercury) 7,296 7,444

Mercury 6,796 6,828

Nutrients 4,525 5,405

Sediment 3,482 4,034

Organic

Enrichment/Oxygen 

Depletion

1,816 1,895

pH/Acidity/Caustic

Conditions 1,675 1,712

Temperature 1,573 1,580

Salinity/Total Dissolved 

Solids/Chlorides/Sulfates 1,523 1,564

Ammonia 1,075 1,138

National Summary of Impaired Waters and TMDL Information | WATERS | US EPA Page 4 of 9

http://iaspub.epa.gov/waters10/attains_nation_cy.control?p_report_type=T 5/24/2010
Total: 41,465 TMDLs; 43,804 Causes of Impairment Addressed 

Approved TMDLs By State 

This chart includes TMDLs since October 1, 1995. 

Description of this table

Pesticides 1,003 1,063

Turbidity 951 1,082

Polychlorinated

Biphenyls (PCBs) 383 404

Chlorine 336 341

Other Cause 208 225

Toxic Inorganics 191 191

Cause Unknown -

Impaired Biota

173 177

Toxic Organics 126 127

Total Toxics 99 107

Habitat Alterations 83 84

Algal Growth 68 73

Trash 65 68

Dioxins 24 25

Noxious Aquatic Plants 21 22

Radiation 21 22

Oil and Grease 12 12

Cause Unknown 5 5

Fish Consumption 

Advisory

2 2

Nuisance Exotic Species 2 2

NOTE: Click on the state name to see a state report. Click on the Number of TMDLs to see a detailed 

list of the TMDLs.

State Name Number of TMDLs

Alabama 265

Alaska 44

American Samoa 2

Arizona 69

Arkansas 232

California 994

Colorado 959

Connecticut 118

Delaware 559

District Of Columbia 360

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http://iaspub.epa.gov/waters10/attains_nation_cy.control?p_report_type=T 5/24/2010
Florida 709

Georgia 1,595

Guam 18

Hawaii 59

Idaho 1,658

Illinois 303

Indiana 768

Iowa 161

Kansas 2,727

Kentucky 125

Louisiana 671

Maine 300

Maryland 617

Massachusetts 426

Michigan 160

Minnesota 1,178

Mississippi 1,387

Missouri 162

Montana 698

Nebraska 91

Nevada 58

New Hampshire 5,518

New Jersey 598

New Mexico 227

New York 640

North Carolina 149

North Dakota 69

Ohio 1,342

Oklahoma 223

Oregon 1,035

Pennsylvania 6,476

Puerto Rico 53

Rhode Island 111

South Carolina 430

South Dakota 276

Tennessee 1,050

Texas 154

Utah 303

National Summary of Impaired Waters and TMDL Information | WATERS | US EPA Page 6 of 9

http://iaspub.epa.gov/waters10/attains_nation_cy.control?p_report_type=T 5/24/2010
Total: 41,465 TMDLs 

National Cumulative Number of TMDLs 

EPA Fiscal Year starts October 1 and ends September 30. 

Description of this table

Total: 41,465 TMDLs; 43,804 Causes of Impairment Addressed 

Status of Available Data Used in This Report 

Description of this table

Vermont 95

Virgin Islands 29

Virginia 1,045

Washington 1,167

West Virginia 2,562

Wisconsin 98

Wyoming 342

NOTE: Click on the underlined "Number of TMDLs Completed" value for

a detailed list of the TMDLs for the fiscal year.

Fiscal

Year Number of TMDLs

Number of 

Causes of

Impairment

Addressed

1996 122 123

1997 338 352

1998 403 409

1999 335 381

2000 1,561 1,586

2001 2,569 2,605

2002 2,747 2,822

2003 2,995 3,272

2004 3,384 3,650

2005 4,254 4,569

2006 4,207 4,559

2007 4,341 4,660

2008 9,241 9,530

2009 4,225 4,446

2010 743 840

State Name Assessed Waters Report Year Impaired Waters Report Year

Alabama 2008 2008

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Alaska 2008 2008

American Samoa 2008 2008

Arizona 2008 2008

Arkansas 2008 2008

California 2004 2006

Colorado 2008 2008

Connecticut 2008 2008

Delaware 2006 2006

District Of Columbia 2008 2008

Florida 2002 2002

Georgia 2008 2008

Guam 2008 2008

Hawaii 2006 2006

Idaho 2008 2008

Illinois 2006 2006

Indiana 2008 2008

Iowa 2008 2006

Kansas 2008 2008

Kentucky 2008 2008

Louisiana 2008 2006

Maine 2008 2008

Maryland 2002 2006

Massachusetts 2006 2006

Michigan 2008 2008

Minnesota 2008 2008

Mississippi 2008 2008

Missouri 2008 2008

Montana 2006 2006

N. Mariana Islands 2008 2008

Nebraska 2008 2008

Nevada 2006 2006

New Hampshire 2008 2008

New Jersey 2008 2008

New Mexico 2008 2008

New York 2008 2008

North Carolina 2006 2006

North Dakota 2008 2008

Ohio 2008 2008

Oklahoma 2008 2008

Oregon 2006 2006

Pennsylvania 2006 2004

Puerto Rico 2008 2008

Rhode Island 2008 2008

South Carolina 2008 2008

South Dakota 2008 2008

Tennessee 2008 2008

Texas 2008 2008

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TMDL Document Search 

Full Text Search of TMDL Documents

Utah 2006 2006

Vermont 2008 2008

Virgin Islands 2008 2008

Virginia 2008 2008

Washington 2008 2008

West Virginia 2008 2008

Wisconsin 2006 2006

Wyoming 2008 2008

National Summary of Impaired Waters and TMDL Information | WATERS | US EPA Page 9 of 9

http://iaspub.epa.gov/waters10/attains_nation_cy.control?p_report_type=T 5/24/2010