Impaired Lakes in Oklahoma
87 of 152 graded Oklahoma lakes (57%) are officially listed as impaired under Clean Water Act §303(d) in the most recent EPA ATTAINS reporting cycle. 20 have an approved TMDL restoration plan.
Top Causes of Impairment in Oklahoma
Reading the Oklahoma impairment landscape
57% of Oklahoma's tracked lakes — 87 of 152 — appear on the EPA Clean Water Act §303(d) impaired-waters list. At that share, impairment is the default state rather than an exception: the majority of lakes are flagged for at least one pollutant exceeding water-quality standards. Trip-planning for clean water in Oklahoma typically requires checking impairment status as a first filter, not as an edge case.
Mercury leads the impairment causes in Oklahoma — a contaminant category that is most relevant for fish consumption rather than for swimming or boating. Mercury and PCB impairments typically come from atmospheric deposition or legacy industrial discharge; they bioaccumulate up the food chain, so larger and longer-lived fish carry the highest tissue concentrations. Check the state's fish-consumption advisory before keeping a catch from these waters.
Impaired-waters listings come from the state environmental agency's §303(d) submission to EPA, refreshed on a roughly 2-year cycle. A listed lake stays on the list until either a TMDL is established and the cleanup completes, or subsequent monitoring shows the pollutant concentrations no longer exceed water-quality standards. The list below reflects the most recent available Oklahoma submission to the EPA Assessment, Total Maximum Daily Load Tracking and Implementation System (ATTAINS) dataset.
All 87 EPA-Listed Impaired Lakes in Oklahoma
| Lake | County | Grade | Causes | TMDL |
|---|---|---|---|---|
| Lake Thunderbird | Cleveland | D | Algal growth, Mercury, Oxygen depletion (low DO) +1 more | ✓ |
| Greenleaf Lake | Muskogee | D | Algal growth, Mercury | — |
| Wes Watkins Reservoir | Pottawatomie | D | Turbidity | — |
| Spavinaw Lake | Mayes | D | Algal growth, Nutrients (phosphorus, nitrogen), Oxygen depletion (low DO) | ✓ |
| Copan Lake | Washington | D | Algal growth, Mercury, Turbidity | ✓ |
| Sportsman Lake | Seminole | D | Mercury | — |
| Wewoka Lake | Seminole | D | Algal growth, Mercury, Turbidity | — |
| Lake Nahni Waiya Tuskahomma | Pushmataha | D | Oxygen depletion (low DO), pH / acidity | — |
| Canton Lake | Blaine | NR | Turbidity | — |
| Boomer Lake | Payne | NR | Algal growth, Mercury, Oxygen depletion (low DO) | ✓ |
| Eufaula Lake | Pittsburg | NR | Mercury | — |
| Fairfax Lake | Osage | NR | Algal growth | — |
| Oologah Lake | Rogers | NR | Oxygen depletion (low DO), Turbidity | ✓ |
| Lake Overholser | Canadian | NR | Salinity / chlorides, Turbidity | — |
| Liberty Lake | Logan | NR | Algal growth, Pathogens (E. coli, fecal), Turbidity | ✓ |
| Elmer Thomas Lake | Comanche | NR | Mercury, Oxygen depletion (low DO) | — |
| Sardis Lake | Pushmataha | NR | Mercury, pH / acidity, Turbidity | — |
| Keystone Lake | Pawnee | NR | Turbidity | — |
| Wister Lake | Le Flore | NR | Algal growth, Mercury, Nutrients (phosphorus, nitrogen) +2 more | ✓ |
| Lake Murray | Carter | NR | Mercury, Oxygen depletion (low DO) | — |
| Rc Longmire Lake | Garvin | NR | Turbidity | — |
| Foss Reservoir | Custer | NR | Turbidity | — |
| Lake Ozzie Cobb | Pushmataha | NR | Mercury, pH / acidity, Turbidity | — |
| Lake Carl Blackwell | Payne | NR | Algal growth, Mercury, Turbidity | ✓ |
| Broken Bow Lake | McCurtain | NR | Mercury, Metals (other than mercury), Oxygen depletion (low DO) +1 more | — |
| Okmulgee Lake | Okmulgee | NR | Mercury, Oxygen depletion (low DO) | — |
| Atoka Lake | Atoka | NR | Algal growth, Mercury, Metals (other than mercury) +1 more | — |
| Lake Henryetta | Okmulgee | NR | Metals (other than mercury), Turbidity | — |
| Webbers Falls Reservoir | Muskogee | NR | Turbidity | — |
| Lake Ellsworth | Comanche | NR | Algal growth, Turbidity | ✓ |
| Lake Ponca | Kay | NR | Algal growth, Mercury, Oxygen depletion (low DO) | ✓ |
| Fort Cobb Reservoir | Caddo | NR | Algal growth, Turbidity | ✓ |
| Robert S Kerr Reservoir | Sequoyah | NR | Turbidity | — |
| Pine Creek Lake | McCurtain | NR | Mercury, Metals (other than mercury), Oxygen depletion (low DO) +1 more | — |
| Stilwell City Lake | Adair | NR | Mercury, Oxygen depletion (low DO), Turbidity | — |
| Stroud Lake | Creek | NR | Mercury | — |
| Hugo Lake | Choctaw | NR | Mercury, Turbidity | — |
| Eufaula Lake | McIntosh | NR | Mercury | — |
| Eufaula Lake | Pittsburg | NR | Mercury | — |
| Lake Lawtonka | Comanche | NR | Algal growth | ✓ |
| Cedar Lake | Le Flore | NR | Mercury, Oxygen depletion (low DO), pH / acidity | — |
| Okemah Lake | Okfuskee | NR | Mercury | — |
| Fort Supply Lake | Woodward | NR | Algal growth, Turbidity | — |
| Lake Stanley Draper | Cleveland | NR | Mercury, Turbidity | — |
| Bluestem Lake | Osage | NR | Turbidity | — |
| Cushing Municipal Lake | Payne | NR | Nutrients (phosphorus, nitrogen), Oxygen depletion (low DO), Turbidity | — |
| Guthrie Lake | Logan | NR | Algal growth, Pathogens (E. coli, fecal) | ✓ |
| Fuqua Lake | Stephens | NR | Algal growth, Turbidity | — |
| Heyburn Lake | Creek | NR | Algal growth, Mercury, Oxygen depletion (low DO) +1 more | — |
| Birch Lake | Osage | NR | Algal growth, Mercury, Oxygen depletion (low DO) | — |
| Skiatook Lake | Osage | NR | Mercury | — |
| Hulah Lake | Osage | NR | Mercury, Turbidity | — |
| Pawnee Lake | Pawnee | NR | Algal growth, Mercury, Turbidity | ✓ |
| Humphreys Lake | Stephens | NR | Algal growth | ✓ |
| Carl Albert Lake | Latimer | NR | Mercury, pH / acidity | — |
| Lone Chimney Lake | Pawnee | NR | Mercury | — |
| Lake Mcmurtry | Noble | NR | Mercury, Turbidity | — |
| Bellcow Lake | Lincoln | NR | Turbidity | — |
| Lake Wayne Wallace | Latimer | NR | Mercury, Oxygen depletion (low DO), pH / acidity | — |
| Chandler Lake | Lincoln | NR | Algal growth, Mercury, Turbidity | — |
| Hefner Lake | Oklahoma | NR | Mercury, Oxygen depletion (low DO) | — |
| Brown Lake | Pittsburg | NR | Metals (other than mercury) | — |
| Great Salt Plains Lake | Alfalfa | NR | Pathogens (E. coli, fecal), Turbidity | — |
| Lake Frederick | Tillman | NR | Mercury, Turbidity | — |
| Fort Gibson Lake | Wagoner | NR | Oxygen depletion (low DO) | ✓ |
| Lake Mcalester | Pittsburg | NR | Mercury, Turbidity | — |
| Sooner Reservoir | Pawnee | NR | Mercury, Oxygen depletion (low DO) | — |
| Tecumseh Lake | Pottawatomie | NR | Turbidity | — |
| Clinton Lake | Washita | NR | Algal growth, Turbidity | — |
| Tenkiller Ferry Lake | Sequoyah | NR | Mercury, Nutrients (phosphorus, nitrogen), Oxygen depletion (low DO) | — |
| Shell Lake | Osage | NR | Algal growth, Mercury, Oxygen depletion (low DO) | — |
| Mcgee Creek Reservoir | Atoka | NR | Mercury, pH / acidity | — |
| Waurika Lake | Jefferson | NR | Algal growth, Mercury, Turbidity | ✓ |
| New Spiro Lake | Le Flore | NR | Algal growth, Oxygen depletion (low DO), pH / acidity | — |
| Arcadia Lake | Oklahoma | NR | Algal growth, Turbidity | — |
| Holdenville Lake | Hughes | NR | Algal growth, Mercury, Oxygen depletion (low DO) +1 more | ✓ |
| Clayton Lake | Pushmataha | NR | Mercury | — |
| Lake Raymond Gary | Choctaw | NR | Mercury | — |
| Duncan Lake | Stephens | NR | Algal growth, Turbidity | — |
| Meeker Lake | Lincoln | NR | Algal growth, Mercury, Turbidity | — |
| Claremore Lake | Rogers | NR | Algal growth | ✓ |
| Rock Creek Reservoir | Carter | NR | Turbidity | — |
| Perry Lake | Noble | NR | Turbidity | — |
| Lake Sahoma | Creek | NR | Mercury | — |
| Crowder Lake | Washita | NR | Algal growth, Turbidity | ✓ |
| Brushy Creek Reservoir | Sequoyah | NR | Algal growth | — |
| Veteran'S Lake | Lincoln | NR | Nutrients (phosphorus, nitrogen), Turbidity | — |
Frequently Asked Questions
How many lakes are impaired in Oklahoma?
87 of 152 graded Oklahoma lakes (57%) are listed as impaired in the most recent EPA ATTAINS reporting cycle. Of those, 81 are on the federal Clean Water Act §303(d) list and 20 have an approved Total Maximum Daily Load (TMDL) restoration plan.
What does Clean Water Act §303(d) mean?
Section 303(d) of the federal Clean Water Act requires every state to identify waters that don't meet water quality standards even after pollution control measures. Each listed water must then have a Total Maximum Daily Load (TMDL) developed — a plan that caps how much of each pollutant can enter the waterbody. The "303(d) list" is the impaired-waters list. The EPA reviews each state's list every two years.
What are the top causes of impairment in Oklahoma?
The most common causes flagged across Oklahoma's impaired lakes are: Mercury (49 lakes); Turbidity (48 lakes); Algal growth (34 lakes); Oxygen depletion (low DO) (24 lakes); pH / acidity (11 lakes); Nutrients (phosphorus, nitrogen) (5 lakes). Mercury is widespread in fish tissue across the upper Midwest from atmospheric deposition. Nutrient impairment (phosphorus, nitrogen) typically reflects agricultural runoff and urban stormwater.
Can I swim in an impaired lake?
It depends on the cause of impairment. A lake impaired for "mercury in fish tissue" is generally safe to swim in — the warning is about long-term consumption of fish. A lake impaired for "pathogens" (E. coli) or "algal growth" may pose a swimming risk and often has a separate beach advisory. Check the cause categories listed for each lake below, and consult your state health department's beach monitoring program for current advisories.
Where does this impairment data come from?
Every impairment record on this page comes from the EPA's ATTAINS (Assessment and TMDL Tracking and Implementation System) public dataset, the federal repository of state-reported water quality assessments. EPA ATTAINS is published as GeoParquet files on the EPA Office of Water S3 bucket and refreshed several times per year. Causes and use-support codes follow EPA's standard taxonomy.
More on impaired waters
What it means when a lake is listed as impaired, why mercury is the most common reason, and why a listed lake can still be clear water with a good grade.
Why states issue fish-consumption advisories, which contaminants — mercury, PCBs, PFAS — drive them, and how to eat the fish you catch more safely.
How phosphorus and nutrient runoff drive algae growth and turn lakes green, where the nutrients come from, and what it means for a lake's grade.
Which lakes are actually improving: multi-year EPA monitoring trends, the named recoveries still in progress, and what it takes to move a letter grade.
Data source
Impairment data from the EPA ATTAINS (Assessment and TMDL Tracking and Implementation System) public dataset. Assessment unit IDs are matched to LakeQuality lakes by name and proximity; some lakes may not appear here if their ATTAINS name doesn't match our naming convention. For an official query, consult Oklahoma's state water-quality agency.