National Summary of State 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.

Frequent Questions

Assessed Waters of United States

Incomplete state reported information may lead to discrepancies and/or missing information in these reports.

Description of this table

	Rivers and Streams (Miles)	Lakes, Reservoirs, and Ponds (Acres)	Bays and Estuaries (Square Miles)	Coastal Shoreline (Miles)	Ocean and Near Coastal (Square Miles)	Wetlands (Acres)	Great Lakes Shoreline (Miles)	Great Lakes Open Water (Square Miles)
	Size of Water
Good Waters	477,805	6,690,496	17,049	973	863	1,307,742	70	1,114
Threatened Waters	9,518	71,165	17			805
Impaired Waters	401,357	11,301,721	11,152	709	4,265	745,616	1,214	210,022

Total Assessed Waters	888,679	18,063,381	28,218	1,681	5,128	2,054,164	1,284	211,136
Total Waters	3,533,205	41,666,049	87,791	58,618	54,120	107,700,000	5,202	60,546
Percent of Waters Assessed	25.2	43.4	32.1	2.9	9.5	1.9	24.7	100.0

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Summary of Water Quality Assessments for Each Waterbody Type

National Summary
Water Quality Attainment in Assessed Rivers and Streams

Description of this table

Assessed Status	Miles

Assessed	888,679
Unassessed	2,644,526
Total Miles	3,533,205

Description of this table

Attainment Status	Miles

Good	477,805
Threatened	9,518
Impaired	401,357
Total Miles Assessed	888,679

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National Summary
Designated Use Support in Assessed Rivers and Streams*

* Waters assessed for more than one designated use are included in multiple designated use groups below.

Description of this table

Designated Use Group		Miles Assessed	Percent Good	Percent Threatened	Percent Impaired	% Good
						% Threatened
						% Impaired
	Fish, Shellfish, And Wildlife Protection And Propagation	523,092	56.6	.6	42.8
	Recreation	239,819	64.8	1.5	33.7
	Agricultural	232,846	90.4	.7	8.9
	Aquatic Life Harvesting	140,185	36.6	4.7	58.6
	Public Water Supply	136,997	77.6	1.4	21.0
	Industrial	108,375	88.9	.1	11.0
	Other	67,207	79.5	.4	20.1
	Aesthetic Value	19,301	72.7	6.5	20.8
	Exceptional Recreational Or Ecological Significance	15,317	13.6	4.2	82.2

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National Summary
Causes of Impairment in Assessed Rivers and Streams

Description of this table

Cause of Impairment Group	Miles Threatened or Impaired
Pathogens	112,084
Sediment	85,248
Nutrients	81,279
Metals (other than Mercury)	61,165
Organic Enrichment/Oxygen Depletion	59,879
Habitat Alterations	58,909
Polychlorinated Biphenyls (PCBs)	44,359
Temperature	38,228
Flow Alteration(s)	36,893
Mercury	34,152
Salinity/Total Dissolved Solids/Chlorides/Sulfates	28,087
pH/Acidity/Caustic Conditions	26,659
Cause Unknown - Impaired Biota	26,424
Cause Unknown	22,607
Turbidity	21,753
Pesticides	15,201
Fish Consumption Advisory	9,715
Other Cause	7,382
Ammonia	6,992
Algal Growth	5,470
Dioxins	5,446
Total Toxics	4,610
Toxic Organics	4,038
Toxic Inorganics	3,015
Oil and Grease	1,838
Chlorine	1,035
Nuisance Exotic Species	999
Taste, Color and Odor	833
Radiation	599
Trash	362
Noxious Aquatic Plants	330
Cause Unknown - Fish Kills	248
Nuisance Native Species	26
Biotoxins	23

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National Summary
Probable Sources of Impairments in Assessed Rivers and Streams

Description of this table

Probable Source Group	Miles Threatened or Impaired
Agriculture	97,558
Unknown	70,561
Hydromodification	62,689
Atmospheric Deposition	49,900
Municipal Dishcarges/Sewage	45,997
Natural/Wildlife	42,808
Unspecified Nonpoint Source	37,494
Habitat Alterations (Not Directly Related To Hydromodification)	36,767
Resource Extraction	29,367
Urban-Related Runoff/Stormwater	29,296
Industrial	24,119
Silviculture (Forestry)	19,126
Legacy/Historical Pollutants	14,615
Construction	14,511
Other	11,326
Land Application/Waste Sites/Tanks	8,171
Spills/Dumping	2,024
Recreation And Tourism (Non-Boating)	1,809
Aquaculture	1,033
Recreational Boating And Marinas	201
Groundwater Loadings/Withdrawals	201
Military Bases	42

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National Summary
Water Quality Attainment in Assessed Lakes, Reservoirs, and Ponds

Description of this table

Assessed Status	Acres

Assessed	18,063,381
Unassessed	23,602,668
Total Acres	41,666,049

Description of this table

Attainment Status	Acres

Good	6,690,496
Threatened	71,165
Impaired	11,301,721
Total Acres Assessed	18,063,381

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National Summary
Designated Use Support in Assessed Lakes, Reservoirs, and Ponds*

* Waters assessed for more than one designated use are included in multiple designated use groups below.

Description of this table

Designated Use Group		Acres Assessed	Percent Good	Percent Threatened	Percent Impaired	% Good
						% Threatened
						% Impaired
	Fish, Shellfish, And Wildlife Protection And Propagation	7,710,776	50.2	.6	49.1
	Recreation	4,488,776	61.4	2.2	36.4
	Agricultural	3,406,492	85.0	1.1	13.8
	Aquatic Life Harvesting	3,231,078	32.3	1.9	65.8
	Public Water Supply	2,969,033	62.5	1.4	36.1
	Industrial	2,747,412	82.7	.1	17.2
	Other	1,890,087	65.2	.5	34.2
	Aesthetic Value	1,230,834	25.8	1.7	72.5
	Exceptional Recreational Or Ecological Significance	732,768	16.1	15.6	68.3

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National Summary
Causes of Impairment in Assessed Lakes, Reservoirs, and Ponds

Description of this table

Cause of Impairment Group	Acres Threatened or Impaired
Mercury	5,984,523
Nutrients	2,516,227
Polychlorinated Biphenyls (PCBs)	2,446,735
Organic Enrichment/Oxygen Depletion	1,939,565
Metals (other than Mercury)	1,346,933
Turbidity	1,022,138
Algal Growth	920,578
Sediment	755,822
Nuisance Exotic Species	624,698
Pathogens	555,258
Flow Alteration(s)	534,641
Salinity/Total Dissolved Solids/Chlorides/Sulfates	512,687
pH/Acidity/Caustic Conditions	497,221
Temperature	486,169
Fish Consumption Advisory	485,508
Habitat Alterations	446,539
Pesticides	335,556
Taste, Color and Odor	281,861
Nuisance Native Species	277,458
Toxic Organics	256,385
Ammonia	138,738
Total Toxics	106,774
Cause Unknown - Impaired Biota	75,855
Noxious Aquatic Plants	51,021
Radiation	48,264
Dioxins	44,931
Cause Unknown	41,421
Oil and Grease	40,903
Biotoxins	9,111
Other Cause	7,442
Toxic Inorganics	6,062
Cause Unknown - Fish Kills	4,614
Trash	1,701
Chlorine	50

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National Summary
Probable Sources of Impairments in Assessed Lakes, Reservoirs, and Ponds

Description of this table

Probable Source Group	Acres Threatened or Impaired
Atmospheric Deposition	3,571,355
Unknown	2,656,091
Agriculture	1,494,046
Hydromodification	1,185,854
Natural/Wildlife	1,159,650
Other	820,570
Legacy/Historical Pollutants	762,587
Unspecified Nonpoint Source	724,617
Urban-Related Runoff/Stormwater	683,293
Municipal Dishcarges/Sewage	547,351
Resource Extraction	512,631
Habitat Alterations (Not Directly Related To Hydromodification)	360,281
Construction	304,812
Silviculture (Forestry)