Impaired Lakes in Wisconsin
307 of 754 graded Wisconsin lakes (41%) are officially listed as impaired under Clean Water Act §303(d) in the most recent EPA ATTAINS reporting cycle. 264 have an approved TMDL restoration plan.
Top Causes of Impairment in Wisconsin
210
Mercury
71
PCBs
58
Oxygen depletion (low DO)
46
Pathogens (E. coli, fecal)
42
PFAS
32
Pesticides
30
Nutrients (phosphorus, nitrogen)
4
Dioxins
All 307 EPA-Listed Impaired Lakes in Wisconsin
| Lake | County | Grade | Causes | TMDL |
|---|---|---|---|---|
| Glen Lake | Leelanau | A | Mercury, Pesticides, PCBs | ✓ |
| Sanford Lake | Benzie | A | Mercury, Oxygen depletion (low DO) | ✓ |
| Second Fortune Lake; Crystal Falls Township | Iron | A | Mercury | ✓ |
| East Arm Grand Traverse Bay 2 Mi From South Shore Lake | Grand Traverse | A | Dioxins, Mercury, Pesticides +2 more | — |
| Sunset Lake West Central Basin; Bates Township | Iron | A | Mercury | ✓ |
| Glen Lake North Cent Basin; Glen Arbor Township Section 35 | Leelanau | A | Mercury, Pesticides, PCBs | ✓ |
| Second Lake | Iron | A | Mercury | ✓ |
| First Lake | Iron | A | Mercury | ✓ |
| First Fortune Lake Central Basin; Crystal F.Township Section 27 | Iron | A | Mercury | ✓ |
| Little Bass Lake | Lake | A | Oxygen depletion (low DO) | — |
| Bills Lake | Newaygo | A | Mercury | ✓ |
| Arbutus Lake | Grand Traverse | A | Mercury | ✓ |
| Whitefish Lake Southeast Basin; Pierson Township | Montcalm | A | Mercury, Oxygen depletion (low DO) | ✓ |
| Whitefish Lake | Montcalm | A | Mercury, Oxygen depletion (low DO) | ✓ |
| Chicagon Lake | Iron | A | Mercury | ✓ |
| Crystal Lake Central Basin; Lake Township Section 12 | Benzie | A | Dioxins, Mercury, Pesticides +1 more | ✓ |
| Arnold Lake | Clare | A | Mercury | ✓ |
| Avery Lake North Basin; T29nr2e | Montmorency | A | Mercury | ✓ |
| Lake Leelanau; North Basin | Leelanau | A | Mercury, PCBs | ✓ |
| Higgins Lake | Roscommon | A | Mercury, Pesticides, PFAS +1 more | ✓ |
| Bills Lake Central Basin | Newaygo | A | Mercury | ✓ |
| Arbutus Lake North Basin | Grand Traverse | A | Mercury | ✓ |
| Arbutus Lake South Central Basin | Grand Traverse | A | Mercury | ✓ |
| Square Lake Central Basin; Bloomfield Township | Oakland | A | Pathogens (E. coli, fecal) | ✓ |
| Square Lake | Oakland | A | Pathogens (E. coli, fecal) | ✓ |
| Round Lake | Emmet | A | Pathogens (E. coli, fecal) | ✓ |
| Arnold Lake North Central Basin; Hayes Township Sec. 2 | Clare | A | Mercury | ✓ |
| Lake Margrethe | Crawford | A | Mercury, PFAS | ✓ |
| Avery Lake | Montmorency | A | Mercury | ✓ |
| Crystal Lake | Benzie | A | Dioxins, Mercury, Pesticides +1 more | ✓ |
| Little Bass Lake | Lake | A | Oxygen depletion (low DO) | — |
| Beaver Lake Central Basin; Ossineke Township | Alpena | A | Mercury | ✓ |
| Beaver Lake | Alpena | A | Mercury | ✓ |
| Margrethe Lake | Crawford | A | Mercury, PFAS | ✓ |
| Chicagon Lake Central Basin; Stambaugh Township | Iron | A | Mercury | ✓ |
| Arbutus Lake North Central Basin | Grand Traverse | A | Mercury | ✓ |
| Arbutus Lake Central Basin | Grand Traverse | A | Mercury | ✓ |
| Lake View; Almira Twp | Benzie | A | Mercury, Oxygen depletion (low DO) | ✓ |
| Shag Lake | Marquette | A | Mercury | ✓ |
| Oxbow Lake | Oakland | A | Nutrients (phosphorus, nitrogen), Pesticides, PCBs | ✓ |
| Burt Lake | Cheboygan | A | Mercury | ✓ |
| Torch Lake | Antrim | A | Dioxins, Mercury, Pesticides +1 more | ✓ |
| Thumb Lake | Charlevoix | A | Mercury | ✓ |
| Lake View | Benzie | A | Mercury, Oxygen depletion (low DO) | ✓ |
| Lake Charlevoix | Charlevoix | A | Pathogens (E. coli, fecal) | ✓ |
| Hubbard Lake Central Basin | Alcona | A | Mercury | ✓ |
| Ransom Lake | Benzie | A | Mercury, Oxygen depletion (low DO) | ✓ |
| Hubbard Lake | Alcona | A | Mercury | ✓ |
| Indian Lake Central Basin; Stambaugh Township | Iron | A | Pathogens (E. coli, fecal) | ✓ |
| Lake Sapphire | Missaukee | A | Metals (other than mercury), Toxic organics | — |
| Manistee North Lake | Manistee | A | Pathogens (E. coli, fecal) | ✓ |
| Manistee Lake South | Manistee | A | Mercury, Pathogens (E. coli, fecal), PCBs | ✓ |
| Walloon Lake | Emmet | A | Mercury, PCBs | ✓ |
| Crooked Lake | Emmet | A | Mercury, PCBs | ✓ |
| Spring Lake | Emmet | A | Pathogens (E. coli, fecal) | ✓ |
| Elk Lake | Antrim | A | Mercury, PCBs | ✓ |
| Lake Charlevoix | Charlevoix | A | Mercury, PCBs | ✓ |
| Cordley Lake Central Basin; Hamburg Township | Livingston | A | Mercury, Pesticides, PFAS +1 more | ✓ |
| Chippewa Lake Northeast Basin; Chippewa Township | Mecosta | A | Mercury | ✓ |
| Lake Ann Southeast Basin; Almira Township Section 26 | Benzie | A | Mercury, Oxygen depletion (low DO) | ✓ |
| Loon Lake | Benzie | A | Oxygen depletion (low DO) | — |
| Silver Lake | Washtenaw | A | Mercury, Pesticides, PFAS +1 more | ✓ |
| Ore Lake West Basin; Hamburg Township | Livingston | A | Mercury, Pesticides, PFAS +1 more | ✓ |
| Gull Lake Central Basin; Ross Township Section 7 | Kalamazoo | A | Mercury, PFAS, PCBs | ✓ |
| Pickerel Lake East Central Basin; Garfield Township Sec. 1 | Newaygo | A | Nutrients (phosphorus, nitrogen), Oxygen depletion (low DO) | — |
| Siskiwit Lake | Keweenaw | A | Mercury, PCBs | ✓ |
| Horsehead Lake Northwest Basin; Martiny Township | Mecosta | A | Mercury, Oxygen depletion (low DO) | ✓ |
| Maceday Lake Central Basin; Waterford Township Section 7 | Oakland | A | Mercury, PCBs | ✓ |
| Cass Lake South Central Basin; W. Bloomfield Township Section 3 | Oakland | A | Mercury, PFAS, PCBs | ✓ |
| Spider Lake West Basin | Grand Traverse | A | Mercury | ✓ |
| Lake Orion East Central Basin; Orion Township Section 11 | Oakland | A | Mercury, Nutrients (phosphorus, nitrogen), Oxygen depletion (low DO) +2 more | — |
| Rose Lake North Basin; Ovid Township | Branch | A | Oxygen depletion (low DO) | — |
| Fremont Lake North Central Basin;Sheridan Township Section 3 | Newaygo | A | Mercury, Oxygen depletion (low DO), PCBs | ✓ |
| Klinger Lake Central Basin; White Pigeon Township Section 1 | St. Joseph | A | Mercury | ✓ |
| Duck Lake; Center of Deepest Basin; Fruitland Township | Muskegon | A | Pathogens (E. coli, fecal) | ✓ |
| Coldwater Lake Southeast Basin; Nottawa Township | Isabella | A | Mercury, Nutrients (phosphorus, nitrogen), Oxygen depletion (low DO) | ✓ |
| Lotus Lake Southeast Basin; Waterford Township Section 5 | Oakland | A | Mercury, PCBs | ✓ |
| Sand Lake Central Basin; Cambridge Township | Lenawee | A | Mercury | ✓ |
| Devils Lake Central Basin North | Lenawee | A | Mercury | ✓ |
| Round Lake Central Basin | Lenawee | A | Mercury | ✓ |
| Upper Woodcock Lake; Almira Twp | Benzie | A | Mercury, Oxygen depletion (low DO) | ✓ |
| Loon Lake; Lake Twp | Benzie | A | Oxygen depletion (low DO) | — |
| Lmj-13 Lake | Cass | A | Oxygen depletion (low DO) | — |
| Lake Lansing Northwest Basin; Meridian Township | Ingham | A | PFAS | — |
| Middle Lake; Elba Township; Section 13 | Lapeer | B | Oxygen depletion (low DO) | — |
| Portage Lake | Livingston | B | Mercury, Pesticides, PFAS +1 more | ✓ |
| Bass Lake | Lake | B | Oxygen depletion (low DO) | — |
| Long Lake | Cass | B | Nutrients (phosphorus, nitrogen), Oxygen depletion (low DO) | — |
| Byram Lake West Central Basin; Fenton Township | Genesee | B | Pathogens (E. coli, fecal) | ✓ |
| Clam Lake | Antrim | B | Mercury | ✓ |
| Gull Lake | Kalamazoo | B | Mercury, PFAS, PCBs | ✓ |
| Chippewa Lake | Mecosta | B | Mercury | ✓ |
| Lake Ann | Benzie | B | Mercury, Oxygen depletion (low DO) | ✓ |
| Silver Lake | Washtenaw | B | Mercury, Pesticides, PFAS +1 more | ✓ |
| Clark Lake Central Basin; Brighton Township | Livingston | B | PCBs | ✓ |
| Pickerel Lake | Newaygo | B | Nutrients (phosphorus, nitrogen), Oxygen depletion (low DO) | — |
| Big Bass Lake North Basin; Elk Township | Lake | B | Oxygen depletion (low DO) | — |
| Long Lake | Oakland | B | Pathogens (E. coli, fecal) | ✓ |
| Byram Lake | Genesee | B | Pathogens (E. coli, fecal) | ✓ |
| Long Lake Central Basin | Oakland | B | Pathogens (E. coli, fecal) | ✓ |
| Bass Lake | Montcalm | B | Mercury | ✓ |
| Portage Lake South Basin; Dexter Township | Washtenaw | B | Mercury, Pesticides, PFAS +1 more | ✓ |
| Cedar Lake Central Basin; Greenbush Township Section 27 | Alcona | B | PFAS | — |
| Long Lake South Central Basin | Cass | B | Nutrients (phosphorus, nitrogen), Oxygen depletion (low DO) | — |
| Clark Lake | Livingston | B | PCBs | ✓ |
| Sunset Lake | Iron | B | Mercury | ✓ |
| Grand Sable Lake | Alger | B | Mercury | ✓ |
| Duck Lake | Muskegon | B | Pathogens (E. coli, fecal) | ✓ |
| Lake Orion | Oakland | B | Mercury, Nutrients (phosphorus, nitrogen), Oxygen depletion (low DO) +2 more | — |
| Spider Lake | Grand Traverse | B | Mercury | ✓ |
| Poor Lake | Gogebic | B | Mercury | ✓ |
| Sylvan Lake | Newaygo | B | Mercury | ✓ |
| Emerald Lake Central Basin; Brooks Township ; Section 6 | Newaygo | B | Mercury | ✓ |
| Round Lake; Independence Township; Section 2 | Oakland | B | Pathogens (E. coli, fecal) | ✓ |
| Hamlin Lake | Mason | B | Mercury, Nutrients (phosphorus, nitrogen), Oxygen depletion (low DO) | ✓ |
| Thousand Island Lake South Basin;Watersmeet Township Sec11 | Gogebic | B | Mercury | ✓ |
| Park Lake | Clinton | B | Pathogens (E. coli, fecal) | ✓ |
| Louis Lake East Central Basin; Waucedah Township | Dickinson | B | Mercury | ✓ |
| Fishhawk Lake East Basin; Watersmeet Township | Gogebic | B | Mercury | ✓ |
| Little Portage Lake Northeast Basin; Dexter Township | Washtenaw | B | Mercury, Pesticides, PFAS +1 more | ✓ |
| Maceday Lake | Oakland | B | Mercury, PCBs | ✓ |
| Silver Lake Central Basin | Genesee | B | Pathogens (E. coli, fecal) | ✓ |
| Base Line Lake | Washtenaw | B | Mercury, Pesticides, PFAS | ✓ |
| Newcomb Lake | Montcalm | B | Mercury | ✓ |
| Long Lake | Gogebic | B | Mercury | ✓ |
| Lotus Lake | Oakland | B | Mercury, PCBs | ✓ |
| Louise Lake | Dickinson | B | Mercury | ✓ |
| Sand Lake | Lenawee | B | Mercury | ✓ |
| Middle Straits Lake | Oakland | B | Mercury | ✓ |
| Lake of the Woods | Branch | B | Oxygen depletion (low DO) | — |
| Newcomb Lake | Montcalm | B | Mercury | ✓ |
| Silver Lake | Genesee | B | Pathogens (E. coli, fecal) | ✓ |
| Sylvan Lake West Central Basin; Brooks Township | Newaygo | B | Mercury | ✓ |
| Hamilton Lake Central Basin | Dickinson | B | Mercury | ✓ |
| Long Lake West Basin | Gogebic | B | Mercury | ✓ |
| Thousand Island Lake | Gogebic | B | Mercury | ✓ |
| Round Lake | Oakland | B | Pathogens (E. coli, fecal) | ✓ |
| Coldwater Lake | Isabella | B | Mercury, Nutrients (phosphorus, nitrogen), Oxygen depletion (low DO) | ✓ |
| Lakeville Lake Central Basin | Oakland | B | Mercury | ✓ |
| Oneida Lake East Central Basin | Livingston | B | Pathogens (E. coli, fecal) | ✓ |
| Cedar Is. Lake East Central Basin,White Lake Township | Oakland | B | Pathogens (E. coli, fecal) | ✓ |
| Whitewood Lake | Livingston | B | Mercury, Pesticides, PFAS +1 more | ✓ |
| Base Line Lake Northeast Basin; Hamburg Township | Livingston | B | Mercury, Pesticides, PFAS | ✓ |
| Mary Lake Central Basin Southeast; Waucedah Township | Dickinson | B | Mercury | ✓ |
| Cedar Island Lake | Oakland | B | Pathogens (E. coli, fecal) | ✓ |
| Lake Independence Central Basin; Powell Township Section 15 | Marquette | B | Mercury | ✓ |
| Horsehead Lake | Mecosta | B | Mercury, Oxygen depletion (low DO) | ✓ |
| Fremont Lake | Newaygo | B | Mercury, Oxygen depletion (low DO), PCBs | ✓ |
| Mary Lake | Dickinson | B | Mercury | ✓ |
| Whitewood Lakes | Livingston | B | Mercury, Pesticides, PFAS +1 more | ✓ |
| Little Portage Lake | Washtenaw | B | Mercury, Pesticides, PFAS +1 more | ✓ |
| Otter Lake North Basin; Waterford Township | Oakland | B | Pathogens (E. coli, fecal) | ✓ |
| Middle Straits Lake Central Basin; West Bloomfield Township | Oakland | B | Mercury | ✓ |
| Cass Lake | Oakland | B | Mercury, PFAS, PCBs | ✓ |
| Otter Lake | Oakland | B | Pathogens (E. coli, fecal) | ✓ |
| Arbutus Lake South Basin | Grand Traverse | B | Mercury | ✓ |
| Record Lake; Central Basin; Watersmeet Township | Gogebic | B | Mercury | ✓ |
| Emerald Lake | Newaygo | B | Mercury | ✓ |
| Lindsley Lake | Gogebic | B | Mercury | ✓ |
| Hamilton Lake | Dickinson | B | Mercury | ✓ |
| Muskegon Lake | Muskegon | B | Mercury, Pesticides, PFAS +1 more | ✓ |
| Devils Lake | Lenawee | B | Mercury | ✓ |
| Upper Long Lake Northwest Basin; Bloomfield Township | Oakland | B | Pathogens (E. coli, fecal) | ✓ |
| Lily Lake North Central Basin; Greenwood Township | Clare | B | Mercury | ✓ |
| Walloon Lake | Charlevoix | B | Mercury, PCBs | ✓ |
| Stager Lake Central Basin | Iron | B | Mercury | ✓ |
| Budd Lake South Basinorth; Hayes Township | Clare | B | Pathogens (E. coli, fecal) | ✓ |
| Deer Lake | Charlevoix | B | Mercury | ✓ |
| Loon Lake | Benzie | B | Oxygen depletion (low DO) | — |
| Bass Lake | Livingston | B | Mercury, Pesticides, PFAS +1 more | ✓ |
| Lower Woodcock Lake | Benzie | B | Mercury, Oxygen depletion (low DO) | ✓ |
| Portage Lake | Manistee | B | Mercury, PCBs | ✓ |
| Mullett Lake | Cheboygan | B | Mercury | ✓ |
| Lower Woodcock Lake; Almira Twp | Benzie | B | Mercury, Oxygen depletion (low DO) | ✓ |
| Bass Lake North Basin; Forsyth Township | Marquette | B | Habitat alterations | — |
| Stager Lake | Iron | B | Mercury | ✓ |
| Elk Lake | Antrim | B | Mercury, PCBs | ✓ |
| Portage Lake Central Basin; Onekama Township | Manistee | B | Mercury, PCBs | ✓ |
| Shag Lake Northeast Basin | Marquette | B | Mercury | ✓ |
| Sanford Lake | Benzie | B | Mercury, Oxygen depletion (low DO) | ✓ |
| Douglas Lake | Cheboygan | B | Mercury | ✓ |
| Bass Lake | Marquette | B | Habitat alterations | — |
| Upper Woodcock Lake | Benzie | B | Mercury, Oxygen depletion (low DO) | ✓ |
| Budd Lake | Clare | B | Pathogens (E. coli, fecal) | ✓ |
| Round Lake | Lenawee | B | Mercury | ✓ |
| Wormer Lake | Oakland | B | Pesticides, PCBs | ✓ |
| Long Lake | Gogebic | B | Mercury | ✓ |
| Mohawk Lake | Oakland | B | Pathogens (E. coli, fecal) | ✓ |
| Maston Lake Northeast Basin; Spencer Township | Kent | B | Pathogens (E. coli, fecal) | ✓ |
| Woodhull Lake Central Basin; Waterford Township | Oakland | B | Pathogens (E. coli, fecal) | ✓ |
| Woodhull Lake | Oakland | B | Pathogens (E. coli, fecal) | ✓ |
| Eagle Lake West Central Basin; Ontwa Township | Cass | B | Mercury | ✓ |
| Brooks Lake | Leelanau | B | Mercury, Pesticides, PCBs | ✓ |
| White L 1000ft Southeast Long Pt; Fruitland Township Section 6 Lake | Muskegon | B | Mercury, PCBs | ✓ |
| White Lake Middle Basin; Fruitland Township | Muskegon | B | Mercury, PCBs | ✓ |
| Barton Lake West Basin; Schoolcraft Township | Kalamazoo | B | Mercury, PCBs | ✓ |
| Park Lake North Central Basin; Bath Township | Clinton | B | Pathogens (E. coli, fecal) | ✓ |
| Duck Lake North Basin; Watersmeet Township | Gogebic | B | Mercury | ✓ |
| Little Platte Lake North Basin | Benzie | B | Mercury, PCBs | ✓ |
| Christiana Lake Central Basin; Ontwa Township | Cass | B | Mercury, Oxygen depletion (low DO) | ✓ |
| Brooks Lake | Leelanau | C | Mercury, Pesticides, PCBs | ✓ |
| White Lake | Muskegon | C | Mercury, PCBs | ✓ |
| Whitmore Lake | Livingston | C | Mercury, PCBs | ✓ |
| Middle Lake | Lapeer | C | Oxygen depletion (low DO) | — |
| Whitmore Lake Northeast Basin; Green Oak Township Sec32 | Livingston | C | Mercury, PCBs | ✓ |
| Kimball Lake Central Basin; Garfield Township | Newaygo | C | Nutrients (phosphorus, nitrogen), Oxygen depletion (low DO) | — |
| Tamarack Lake | Livingston | C | Mercury, Pesticides, PFAS +1 more | ✓ |
| Cedar Lake | Alcona | C | PFAS | — |
| Lakeville Lake | Oakland | C | Mercury | ✓ |
| Great Bear Lake | Van Buren | C | Nutrients (phosphorus, nitrogen) | ✓ |
| Duck Lake | Gogebic | C | Mercury | ✓ |
| Fishhawk Lake | Gogebic | C | Mercury | ✓ |
| Dollar Lake | Oakland | C | Pathogens (E. coli, fecal) | ✓ |
| Barton Lake | Kalamazoo | C | Mercury, PCBs | ✓ |
| Tamarack Lake North Basin; Hamburg Township | Livingston | C | Mercury, Pesticides, PFAS +1 more | ✓ |
| Morley Lake | Gogebic | C | Mercury | ✓ |
| Aginaw Lake | Shiawassee | C | Oxygen depletion (low DO) | — |
| Oneida Lake | Livingston | C | Pathogens (E. coli, fecal) | ✓ |
| Big African Lake | Gogebic | C | Mercury | ✓ |
| Record Lake | Gogebic | C | Mercury | ✓ |
| Sylvan Lake; Sylvan Lake Township | Oakland | C | Pathogens (E. coli, fecal) | ✓ |
| Cranberry Lake | Oakland | C | Pathogens (E. coli, fecal) | ✓ |
| Lake Independence | Marquette | C | Mercury | ✓ |
| Big Affrica Lake; Central Basin; Watersmeet Township | Gogebic | C | Mercury | ✓ |
| Aginaw Lake; Anrtrim Township; Section 13 | Shiawassee | C | Oxygen depletion (low DO) | — |
| Sylvan Lake | Oakland | C | Pathogens (E. coli, fecal) | ✓ |
| Cable Lake | Iron | C | Mercury, PFAS | ✓ |
| Perch Lake Central Basin; Bates Township | Iron | C | Mercury | ✓ |
| Cable Lake Central Basin | Iron | C | Mercury, PFAS | ✓ |
| Klinger Lake | St. Joseph | C | Mercury | ✓ |
| Stony Lake West Basin North | Oceana | C | Oxygen depletion (low DO) | — |
| Devils Head Lake | Gogebic | C | Mercury | ✓ |
| Cisco Lake Central Basin; Watersmeet Township | Gogebic | C | Mercury | ✓ |
| Lily Lake | Clare | C | Mercury | ✓ |
| Mitchell Lake Southeast Basin; Cherry Grove Township Section 12 | Wexford | C | Mercury | ✓ |
| Lake Victoria | Clinton | C | Pathogens (E. coli, fecal) | ✓ |
| Painter Lake Central Basin; Jefferson Township; T7s R14w; Section 36 | Cass | C | Mercury | ✓ |
| Christiana Lake | Cass | C | Mercury, Oxygen depletion (low DO) | ✓ |
| Baldwin Lake Northwest Basin | Cass | C | Oxygen depletion (low DO) | — |
| Pleasant Lake | Oakland | C | Mercury | ✓ |
| Pickerel Lake | Emmet | C | Mercury | ✓ |
| Victoria Lake North of Central Island; Victor Township | Clinton | C | Pathogens (E. coli, fecal) | ✓ |
| Lake Mitchell | Wexford | C | Mercury | ✓ |
| Pleasant Lake; West Bloomfield Township | Oakland | C | Mercury | ✓ |
| Juno Lake Central Basin; Mason Township | Cass | C | Mercury | ✓ |
| Lake Gogebic | Gogebic | C | Mercury | ✓ |
| Lake Paradise | Emmet | C | Mercury | ✓ |
| Lake Bellaire | Antrim | C | Mercury | ✓ |
| Baldwins Lake | Cass | C | Oxygen depletion (low DO) | — |
| Bass Lake | Livingston | C | Mercury, Pesticides, PFAS +1 more | ✓ |
| Upper Long Lake | Oakland | C | Pathogens (E. coli, fecal) | ✓ |
| Lake Gogebic; South Deep Basin; Marenisco Township | Gogebic | C | Pathogens (E. coli, fecal) | ✓ |
| Langford Lake; Deepest Basin; Watersmeet Township | Gogebic | C | Mercury | — |
| Bennett Lake; Deep Basin; Deerfield Township | Livingston | C | Mercury, PFAS | ✓ |
| Lobdell Lake West Basin; Argentine Township | Genesee | C | Mercury, PCBs | ✓ |
| Maston Lake | Kent | C | Pathogens (E. coli, fecal) | ✓ |
| Van Etten Lake North Central Basin; Oscoda Township | Iosco | C | Mercury, Nutrients (phosphorus, nitrogen), PFAS +1 more | ✓ |
| Earl Lake Central Basin | Livingston | C | PFAS, PCBs, Salinity / chlorides | ✓ |
| Rose Lake | Shiawassee | C | Oxygen depletion (low DO) | — |
| Lake Ovid North Basin; Ovid Township | Clinton | C | Pathogens (E. coli, fecal) | ✓ |
| Flint Park Lake | Genesee | C | PFAS | — |
| Round Lake | Shiawassee | C | Oxygen depletion (low DO) | — |
| Thread Lake Central Basin | Genesee | C | Nutrients (phosphorus, nitrogen), PCBs | ✓ |
| Dollar Lake; Independence Township; Section 2 | Oakland | C | Pathogens (E. coli, fecal) | ✓ |
| Crockery Lake Southwest Basin; Chester Township | Ottawa | C | Mercury, Nutrients (phosphorus, nitrogen), Oxygen depletion (low DO) | ✓ |
| Moore Lake | Allegan | C | Mercury | ✓ |
| Kimball Lake | Newaygo | D | Nutrients (phosphorus, nitrogen), Oxygen depletion (low DO) | — |
| Van Etten Lake | Iosco | D | Mercury, Nutrients (phosphorus, nitrogen), PFAS +1 more | ✓ |
| Eagle Lake | Cass | D | Mercury | ✓ |
| Earl Lake | Livingston | D | PFAS, PCBs, Salinity / chlorides | ✓ |
| Great Bear Lake North Basin; Bloomingdale Township | Van Buren | D | Nutrients (phosphorus, nitrogen) | ✓ |
| Crockery Lake | Ottawa | D | Mercury, Nutrients (phosphorus, nitrogen), Oxygen depletion (low DO) | ✓ |
| Clearwater Lake Central Basin; T45n | Gogebic | D | Mercury | ✓ |
| Rose Lake | Shiawassee | D | Oxygen depletion (low DO) | — |
| Lake Ovid | Clinton | D | Mercury, Nutrients (phosphorus, nitrogen) | ✓ |
| Little Platte Lake | Benzie | D | Mercury, PCBs | ✓ |
| Union Lake | Branch | D | Nutrients (phosphorus, nitrogen), PCBs | ✓ |
| Perch Lake | Iron | D | Mercury | ✓ |
| Round Lake | Shiawassee | D | Oxygen depletion (low DO) | — |
| Clearwater Lake | Gogebic | D | Mercury | ✓ |
| Union Lake Southwest Basin; Sherwood Township Section 11 | Branch | D | Nutrients (phosphorus, nitrogen), PCBs | ✓ |
| Flint Park Lake | Genesee | D | PFAS | — |
| Little African Lake | Gogebic | D | Mercury | ✓ |
| Stony Lake | Oceana | D | Oxygen depletion (low DO) | — |
| Little Africa Lake; Central Basin; Watersmeet Township | Gogebic | D | Mercury | ✓ |
| Carter Lake | Barry | D | Mercury | ✓ |
| Juno Lake | Cass | D | Mercury | ✓ |
| Cisco Lake | Gogebic | D | Mercury | ✓ |
| Carter Lake Northwest Basin | Barry | D | Mercury | ✓ |
| Painter Lake | Cass | D | Mercury | ✓ |
| Tull Lake Central Basin; White Lake Township | Oakland | D | Nutrients (phosphorus, nitrogen), Pesticides, PCBs | ✓ |
| Little Paw Paw Lake | Berrien | D | Mercury, Nutrients (phosphorus, nitrogen), Oxygen depletion (low DO) +1 more | ✓ |
| Lake Diane South Basin; Amboy Township | Hillsdale | D | Nutrients (phosphorus, nitrogen) | — |
| Fox Lake Central Basin; Dalton Township | Muskegon | D | Pathogens (E. coli, fecal) | ✓ |
| Palmer Lake Central Basin; Colon Township | St. Joseph | D | Mercury | ✓ |
| Crockery Lake Northeast Basin; Chester Township | Ottawa | F | Mercury, Nutrients (phosphorus, nitrogen), Oxygen depletion (low DO) | ✓ |
| Little Paw Paw Lake | Berrien | F | Mercury, Nutrients (phosphorus, nitrogen), Oxygen depletion (low DO) +1 more | ✓ |
| Little Paw Paw Lake West Central Basin; Coloma Township | Berrien | F | Mercury, Nutrients (phosphorus, nitrogen), Oxygen depletion (low DO) +1 more | ✓ |
| Thread Lake | Genesee | F | Nutrients (phosphorus, nitrogen), PCBs | ✓ |
| Palmer Lake | St. Joseph | F | Mercury | ✓ |
| Fox Lake | Muskegon | F | Pathogens (E. coli, fecal) | ✓ |
| First Sister Lake | Washtenaw | F | Mercury | ✓ |
| Second Sister Lake | Washtenaw | F | Mercury | ✓ |
| Sturgeon Lake; Center of Deepest Basin; Colon Township | St. Joseph | F | PFAS | — |
| Ford Lake Central Basin; Ypsilanti Township | Washtenaw | F | Mercury, Pesticides, PFAS +1 more | ✓ |
| Swan Lake West Central Basin,Cheshire Township | Allegan | F | Nutrients (phosphorus, nitrogen) | — |
| Sassafras Lake | Van Buren | F | Mercury | ✓ |
Frequently Asked Questions
How many lakes are impaired in Wisconsin?
307 of 754 graded Wisconsin lakes (41%) are listed as impaired in the most recent EPA ATTAINS reporting cycle. Of those, 175 are on the federal Clean Water Act §303(d) list and 264 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 Wisconsin?
The most common causes flagged across Wisconsin's impaired lakes are: Mercury (210 lakes); PCBs (71 lakes); Oxygen depletion (low DO) (58 lakes); Pathogens (E. coli, fecal) (46 lakes); PFAS (42 lakes); Pesticides (32 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.
Data source
Impairment data from the EPA ATTAINS (Assessment and TMDL Tracking and Implementation System) public dataset. Assessment unit IDs are matched to LakeGrade waterbodies 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 Wisconsin's state water-quality agency.