Wisconsin Lake Water Quality
Water quality grades for 2,110 monitored lakes across 70 counties.
A
1466
Excellent
B
312
Good
C
176
Fair
D
111
Poor
F
45
Very Poor
Counties
A
Unknown County
17 lakes
A
Kewaunee County
7 lakes
A
Trempealeau County
1 lakes
A
Oneida County
1 lakes
A
Florence County
51 lakes
A
Marinette County
27 lakes
A
Waupaca County
45 lakes
A
Waukesha County
30 lakes
A
Ashland County
21 lakes
A
Bayfield County
93 lakes
A
Walworth County
69 lakes
A
Vernon County
245 lakes
A
Monroe County
82 lakes
A
Iron County
50 lakes
A
Forest County
43 lakes
A
Burnett County
76 lakes
A
Langlade County
38 lakes
A
Sawyer County
98 lakes
A
Polk County
31 lakes
A
Kenosha County
15 lakes
A
Washburn County
16 lakes
A
Sheboygan County
9 lakes
A
Adams County
30 lakes
A
Washington County
68 lakes
A
Jackson County
4 lakes
B
Oconto County
167 lakes
B
Door County
21 lakes
B
Shawano County
31 lakes
B
Manitowoc County
28 lakes
B
Rock County
16 lakes
B
Douglas County
70 lakes
B
Lincoln County
27 lakes
B
Menominee County
64 lakes
B
Marquette County
18 lakes
B
Richland County
6 lakes
B
Vilas County
43 lakes
B
Barron County
58 lakes
B
Pierce County
113 lakes
B
Price County
10 lakes
B
Portage County
27 lakes
B
Chippewa County
25 lakes
B
Brown County
4 lakes
B
Outagamie County
12 lakes
B
Rusk County
9 lakes
B
Fond du Lac County
12 lakes
B
St. Croix County
7 lakes
B
Jefferson County
10 lakes
C
Iowa County
6 lakes
C
Sauk County
21 lakes
C
Winnebago County
4 lakes
C
Pepin County
2 lakes
C
Waushara County
12 lakes
C
Columbia County
15 lakes
C
Racine County
2 lakes
C
Lafayette County
5 lakes
C
Green Lake County
18 lakes
C
Grant County
4 lakes
C
Eau Claire County
6 lakes
C
Dunn County
7 lakes
D
Dane County
28 lakes
D
Juneau County
2 lakes
D
Marathon County
13 lakes
D
Green County
1 lakes
D
Calumet County
3 lakes
D
Clark County
6 lakes
D
Dodge County
6 lakes
D
Milwaukee County
1 lakes
D
Crawford County
1 lakes
F
La Crosse County
1 lakes
F
Ozaukee County
1 lakes
Top 25 Cleanest Lakes
| Rank | Lake | County | Grade |
|---|---|---|---|
| 1 | Geneva Lake | Vilas | A |
| 2 | Lac Courte Oreilles Lake | Sawyer | A |
| 3 | Lac Courte Oreilles Lake | Sawyer | A |
| 4 | Sunset Lake - | Polk | A |
| 5 | Lake Michigan - Outer Harbor Oh | Menominee | A |
| 6 | Lake Michigan | Menominee | A |
| 7 | Grindstone Lake | Sawyer | A |
| 8 | Middle Sugarbush Lake - | Vernon | A |
| 9 | Irving Lake - Island Site | Vernon | A |
| 10 | Windigo Lake - | Sawyer | A |
| 11 | Towanda Lake - | Vernon | A |
| 12 | Parker Lake - | Adams | A |
| 13 | Lac Courte Oreilles - Musky Bay Lake | Sawyer | A |
| 14 | West Bay Deep Hole Lake | Vernon | A |
| 15 | Long Lake - | Waupaca | A |
| 16 | Long Lake - | Lincoln | A |
| 17 | Long Lake - | Fond du Lac | A |
| 18 | Chain Lake - Ferndale Area | Chippewa | A |
| 19 | Upper Eau Claire Lake - | Bayfield | A |
| 20 | Spring Lake - Spring Lake Sw End | Waupaca | A |
| 21 | Black Hawk Lake - | Iowa | A |
| 22 | Lake Michigan | Menominee | A |
| 23 | Spider Lake # 5 - North Basin | Walworth | A |
| 24 | Silver Lake - | Waukesha | A |
| 25 | Silver Lake - | Washington | A |
25 Lakes Needing Attention
| Rank | Lake | County | Grade |
|---|---|---|---|
| 1 | Lower Kelly Lake - | Washington | F |
| 2 | Mead Lake - East | Clark | F |
| 3 | Grafton Millpond | Outagamie | F |
| 4 | Giltners Lake - | Fond du Lac | F |
| 5 | Thiensville Millpond | Outagamie | F |
| 6 | Graber Pond - Middleton | Dane | F |
| 7 | County K Marsh Lake | Green Lake | F |
| 8 | Silver Creek Estuary Lake | Green Lake | F |
| 9 | Mead Lake - West | Clark | F |
| 10 | Green Lake - | Green Lake | F |
| 11 | Green Lake - E | Green Lake | F |
| 12 | Little Yellow Lake - Site A | Burnett | F |
| 13 | Hawthorne Hills South Pond | Dane | F |
| 14 | Mb-2a Cul Lake | Sawyer | F |
| 15 | Beaver Dam Lake - Rakes | Dodge | F |
| 16 | Moon Lake - Moon Lake | Barron | F |
| 17 | Cathedral Point Pond | Dane | F |
| 18 | Horseshoe Lake - West | Pierce | F |
| 19 | Prairie Oaks Pond | Dane | F |
| 20 | Gateway Pond | Dane | F |
| 21 | Outlet To Lake Geneva, Unnamed | Vilas | F |
| 22 | Silent Street Pond | Dane | F |
| 23 | Investment Court Pond | Dane | F |
| 24 | Little St. Germain Lake-West Bay-at St. Germain | Vernon | F |
| 25 | Hill Slough - East Lake | Sauk | F |