Wisconsin Lake Water Quality
Water quality grades for 388 monitored lakes across 82 counties.
A-grade lakes are scarce in Missouri: about 5% of the dataset. Most lakes here sit in C or D — productive, often shallow, frequently algal in late summer.
Eutrophic conditions dominate — nutrient-loaded, productive, with algal pressure that shows up most years in late summer. These lakes tend to be shallow, agricultural-watershed, and over-warmed by the time July ends. The cleanest county on average is Oregon (grade A); the most-stressed is Polk. The gap between the top and bottom counties is large enough that "Missouri lake water quality" hides real local variation.
Lake Map
Reservoirs in Wisconsin
View all 205 reservoirs →205 of 388 Wisconsin lakes (53%) are man-made reservoirs in the USACE National Inventory of Dams. 162 carry a High or Significant hazard rating. The oldest matched dam dates to 1870.
EPA-Impaired Lakes in Wisconsin
View all 145 impaired lakes →145 of 388 Wisconsin lakes (37%) are officially listed as impaired under Clean Water Act §303(d) in the most recent EPA ATTAINS reporting cycle. 14 have an approved Total Maximum Daily Load (TMDL) restoration plan.
Counties
Top 25 Cleanest Lakes
| Rank | Lake | County | Grade | Clarity | Max Depth |
|---|---|---|---|---|---|
| 1 | Lake Capri | St. Francois | A | 16.3 ft | - |
| 2 | Stockton Lake | Cedar | A | - | - |
| 3 | Lake Wauwanoka Nr. Dam | Jefferson | A | 12.9 ft | - |
| 4 | Lake Marseilles-Terre du Lac Lakes | St. Francois | A | 14.1 ft | - |
| 5 | Lake Shayne-Terre du Lac Lakes | Washington | A | 11.1 ft | - |
| 6 | Timberline Lakes | St. Francois | A | 14.3 ft | - |
| 7 | Alpine Lake | Warren | A | 12.6 ft | - |
| 8 | Lake Taneycomo Ab. Bee Cr. Arm | Taney | A | 13.3 ft | - |
| 9 | Lake Taneycomo Nr. Roark Cr. | Taney | A | 12.6 ft | - |
| 10 | Council Bluff Lake | Iron | A | 13.1 ft | - |
| 11 | Mccormack Lake | Oregon | A | 11.7 ft | - |
| 12 | Fourche Creek Lake | Ripley | A | 13.6 ft | - |
| 13 | Goose Creek Lake | Ste. Genevieve | A | 9.9 ft | - |
| 14 | Oasis Ranch Lake | Audrain | A | 14.1 ft | - |
| 15 | Port Perry Lake | Perry | A | 12 ft | - |
| 16 | Oasis Ranch Upper Lake | Audrain | A | 14.4 ft | - |
| 17 | Lake Taneycomo @ Shepherd of the Hills Fh | Taney | A | - | - |
| 18 | Cattails 2 Lake | Jefferson | A | - | - |
| 19 | Lake Taneycomo @ Rockaway Beach | Taney | B | 8.7 ft | - |
| 20 | Fox Valley Lake | Clark | B | 8.5 ft | - |
| 21 | Cole Lake | Jefferson | B | 18.5 ft | - |
| 22 | Fellows Lake | Greene | B | 7.2 ft | - |
| 23 | Lake Konstanz | Warren | B | 7.7 ft | - |
| 24 | Table Rock Lk. Into Main Channel From Dam Lake | Stone | B | 7.2 ft | - |
| 25 | Table Rock L. Ab. Carter Br. Lake | Barry | B | 6.8 ft | - |
25 Lakes Needing Attention
| Rank | Lake | County | Grade | Clarity |
|---|---|---|---|---|
| 1 | Englewood Park Lake | Clay | F | - |
| 2 | Loose Park Lake | Jackson | F | - |
| 3 | Perry City Lake | Ralls | F | - |
| 4 | Limpp Lake | Gentry | F | - |
| 5 | Memphis Lake No.1 | Scotland | F | - |
| 6 | Washington Lake | Jackson | F | - |
| 7 | Catclaw Lake | Jackson | F | - |
| 8 | Blue River Parkway Lake | Jackson | F | - |
| 9 | Kessler Lake | Jackson | F | - |
| 10 | Chaumiere Park Lake | Clay | F | - |
| 11 | Lake of the Woods | Jackson | F | - |
| 12 | Firehouse Park Lake | Jackson | F | - |
| 13 | Troost Lake | Jackson | F | - |
| 14 | Tilles Park Reservoir | St. Louis | F | - |
| 15 | Big Lake | Holt | F | - |
| 16 | Troost Lake | Jackson | F | - |
| 17 | Lewis Lake | Stoddard | F | - |
| 18 | Railraod Lake | Moniteau | F | - |
| 19 | Lake Wooldridge | Saline | F | - |
| 20 | Lake Taneycomo | Taney | F | - |
| 21 | Unnamed Lake Near | Callaway | F | 2.3 ft |
| 22 | Mckee Prairie Pond | Jackson | F | 1.3 ft |
| 23 | Kruse Lake | St. Charles | F | 2.6 ft |
| 24 | Bee Tree Lake | St. Louis | F | 0.6 ft |
| 25 | Jamesport Community Lake | Daviess | F | 0.9 ft |
Source: EPA National Aquatic Resource Surveys, 2026.