Minnesota vs Wisconsin — Lake Water Quality Comparison
A data-driven comparison of lake water quality between the two premier lake states.
| Minnesota | Wisconsin | |
|---|---|---|
| Total Lakes | 2,248 | 1,522 |
| Average Grade | C | B |
| Average Score | 2.3 | 3.36 |
| Grade A Lakes | 657 | 1,040 |
| Grade B Lakes | 533 | 243 |
| Grade C Lakes | 453 | 128 |
| Grade D Lakes | 324 | 82 |
| Grade F Lakes | 281 | 29 |
| Oligotrophic (Cleanest) | 482 | 916 |
| Eutrophic (High Nutrient) | 753 | 199 |
| Fish Species Documented | 71 | 9 |
| Lakes with Fish Data | 1,546 | 1,208 |
| Lakes with Invasives | 765 | 927 |
| Average Depth (ft) | 45 ft | 37 ft |
| Lakes with Depth Data | 1,739 | 1,110 |
| Improving Trend | 657 | 577 |
| Declining Trend | 677 | 391 |
| Ice Data Available | 1,030 | 0 |
Analysis
Both Minnesota and Wisconsin are among the best lake states in the country. Minnesota has more total lakes and more ice data (the MN DNR has tracked ice-out dates for decades). Wisconsin's Northwoods region (Vilas, Oneida, Forest counties) has some of the cleanest lakes in either state.
For fishing, Wisconsin is considered the musky capital of the world, while Minnesota's walleye fisheries (Mille Lacs, Vermilion, Leech) are legendary. Both states have excellent smallmouth bass and panfish lakes.
Frequently Asked Questions
Does Minnesota or Wisconsin have cleaner lakes?
Minnesota has an average lake grade of C (score 2.3) while Wisconsin averages B (score 3.36). Wisconsin has slightly better average water quality, though both states have excellent lakes.
Which state has more lakes?
Minnesota has 2,248 graded lakes while Wisconsin has 1,522. Minnesota is known as the "Land of 10,000 Lakes" and has more monitored waterbodies.
Which state has more fish species?
Minnesota lakes have 71 documented species across 1,546 lakes, while Wisconsin has 9 species across 1,208 lakes.