Updated Aug 2026
Michigan Lake Water Quality
Water quality grades for 592 monitored lakes across 70 counties.
Across Michigan, 592 lakes carry an active water-quality grade spread over 70 counties. The underlying measurements come from the Michigan Department of Environment, Great Lakes, and Energy (EGLE), alongside federal programs and volunteer monitoring networks. Around 18% of the state's lakes pull an A — 107 top-tier waters. The B and C brackets together hold most of the rest, with the F bracket capturing 1 stressed lakes mostly in the agricultural south of the state.
Most Michigan lakes sit in the mesotrophic band — moderate productivity, decent clarity, capable of supporting both warm-water and cool-water fisheries. This is the band where well-managed working lakes tend to land. The cleanest county on average is Dickinson (grade A); the most-stressed is Shiawassee. The gap between the top and bottom counties is large enough that "Michigan lake water quality" hides real local variation.
Grade Distribution
All 592 Michigan lakes in the index: 182 (30.7%) carry an A–F grade and 410 (69.3%) are not rated, because they lack enough recent nutrient or algae sampling to support a letter.
Where to stay near Michigan
Top-rated places to stay near Michigan
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Top-Graded Michigan Lakes
The highest water-quality grades in Michigan — clarity, depth, and A-F grade at a glance.
Lake Map
Explore Michigan Lakes
Michigan reports, fishing & travel
Michigan's cleanest and most-polluted lakes, ranked A–F
Fish species and top-graded lakes across Michigan
Species activity outlook by water temperature and season
Where to stay at Michigan's top lakes, each with its grade
Best-graded lakes within 50 miles of Detroit
Best-graded lakes within 50 miles of Grand Rapids
Best-graded lakes within 50 miles of Traverse City
Reservoirs in Michigan
View all 66 reservoirs →66 of 592 Michigan lakes (11%) are man-made reservoirs in the USACE National Inventory of Dams. 28 carry a High or Significant hazard rating. The oldest matched dam dates to 1829.
EPA-Impaired Lakes in Michigan
View all 256 impaired lakes →256 of 592 Michigan lakes (43%) are officially listed as impaired under Clean Water Act §303(d) in the most recent EPA ATTAINS reporting cycle. 218 have an approved Total Maximum Daily Load (TMDL) restoration plan.
Michigan Fishing & Recreation
Licenses, regulations, records, and where to fish across Michigan.
Counties
All 70 Michigan counties, ranked by average lake water quality. Compare them against every county nationwide in the county rankings, browse the full directory of graded lakes, or pick a different state.
Michigan Lake Water Quality Dataset (2026)
Every graded Michigan lake in one spreadsheet — A–F grade, water clarity, phosphorus, chlorophyll-a, trophic state, size, public access, and a link to each lake's report card.
Top 25 Cleanest Lakes
25 lakes25 graded lakes
| # | Lake | County | Grade | Clarity | Trophic | Max Depth | Access |
|---|---|---|---|---|---|---|---|
| 1 | ABostwick Lake Central Basin; Cannon Township | Kent | A | 8.8 ft | Mesotrophic | 24 ft | Not recorded |
| 2 | ACrystal Lake Central Basin; Crystal Township | Montcalm | A | 10 ft | Mesotrophic | 70 ft | ✓ Public |
| 3 | AOre Lake West Basin; Hamburg Township | Livingston | A | 9 ft | Mesotrophic | 81 ft | ✓ Public |
| 4 | ALake Twenty (Aka | Gladwin | A | 8.5 ft | Mesotrophic | No recent samples | Not recorded |
| 5 | ALouis Lake East Central Basin; Waucedah Township | Dickinson | A | 13.5 ft | Mesotrophic | No recent samples | Not recorded |
| 6 | ASouth Bar Lake; Center of | Leelanau | A | 8.5 ft | Mesotrophic | 13 ft | Not recorded |
| 7 | ALake Leelanau; North Basin | Leelanau | A | 16 ft | Oligotrophic | No recent samples | ✓ Public |
| 8 | ADuncan Lake South Central Basin | Barry | A | 3.5 ft | Mesotrophic | 55 ft | Not recorded |
| 9 | AEagle Lake Central Basin; Blue Lake Township | Kalkaska | A | 18 ft | Oligotrophic | 20 ft | Not recorded |
| 10 | AIron Lake South Central Basin; Stambaugh Township | Iron | A | 9 ft | Mesotrophic | 45 ft | Not recorded |
| 11 | AMary Lake Central Basin Southeast; Waucedah Township | Dickinson | A | 14.5 ft | Oligotrophic | No recent samples | ✓ Public |
| 12 | ADiamond Lake East Basin; Penn Township | Cass | A | 12.3 ft | Oligotrophic | 64 ft | Not recorded |
| 13 | AGlacier Lake | Washtenaw | A | 6 ft | Mesotrophic | No recent samples | Not recorded |
| 14 | AEllen Lake South Central Basin; Mansfield Township | Iron | A | 17.3 ft | Oligotrophic | 73 ft | Not recorded |
| 15 | ABrooks Lake | Leelanau | A | 9.5 ft | Mesotrophic | No recent samples | Not recorded |
| 16 | AIndian Lake Central Basin; Brady Township | Kalamazoo | A | 9.5 ft | Mesotrophic | 75 ft | Not recorded |
| 17 | ARound Lake North Basin | Mecosta | A | 9 ft | Mesotrophic | 45 ft | Not recorded |
| 18 | ALong Lake North Central Basin; Plainfield Township | Iosco | A | 14 ft | Oligotrophic | 62 ft | Not recorded |
| 19 | AMecosta Lake North Basin; Morton Township | Mecosta | A | 9.5 ft | Mesotrophic | 39 ft | Not recorded |
| 20 | APerch Lake Central Basin; Bates Township | Iron | A | 6 ft | Mesotrophic | 14 ft | Not recorded |
| 21 | ARennie Lake; Central Basin; East Bay Township | Grand Traverse | A | 14 ft | Mesotrophic | 27 ft | Not recorded |
| 22 | AEmerald Lake | Kent | A | 11.5 ft | Mesotrophic | No recent samples | Not recorded |
| 23 | ALancelot Lake Southwest Basin | Gladwin | A | 9 ft | Mesotrophic | No recent samples | ✓ Public |
| 24 | ASawyer Lake Central Basin; Sagola Township | Dickinson | A | 7 ft | Mesotrophic | 20 ft | ✓ Public |
| 25 | AHanbury Lake; Norway Township | Dickinson | A | 14 ft | Mesotrophic | No recent samples | ✓ Public |
25 Lakes Needing Attention
25 lakes25 graded lakes
Lake Match
Which lake suits how you actually use one?
Six questions — swimming, fishing, quiet, cabins, drive time — and a shortlist of graded lakes that fit, with the water quality behind each one.
Source: EPA National Aquatic Resource Surveys and the EPA Water Quality Portal.
More on lake water quality
The top-graded lake in every state we cover, picked grade-first with water clarity as the tie-breaker — plus the states whose winner is still not clean.
State-by-state Secchi champions: the clearest measured lake in each U.S. state we grade, which is not the same as the cleanest nutrient grade.
A data snapshot of the lakes we grade: how the A–F distribution breaks down, the clearest and the greenest states, and where the water is improving.
How lakes are graded A–F on nutrients and algae using EPA ecoregion condition classes, what each letter means in the water, and why an A is not a clearance.