State water-quality picture · #3 by reported lake-type waterbodies
Michigan lakes and reservoirs
Every figure on this page is computed from the assessment decisions Michigan and the Little River Band of Ottawa Indians reported to the U.S. Environmental Protection Agency under Clean Water Act sections 303(d) and 305(b) (reporting cycles 2018–2026), plus daily water-level observations from the U.S. Geological Survey.
- 4,307
- Reported waterbodies
- 807
- Not supporting a use
- 578
- Fish use not supporting
- 8
- Gauged lakes
Michigan in one line
4,307 lake-type waterbodies in Michigan are reported to EPA ATTAINS across reporting cycles 2018–2026: 807 assessed as not supporting at least one designated use, 3,457 fully supporting, and 43 without a definitive overall verdict. The most-listed impairment cause is Mercury in Fish Tissue, on 525 waterbodies. This ranks the cause names filed in Michigan, not distinct pollutants: mercury appears under 2 of them, together listed on 525 waterbodies.
- 4,307
- reported waterbodies
- 807
- not supporting a use
- 3,457
- fully supporting
- 35%
- of definitive verdicts impaired
An unassessed waterbody is neither confirmed clean nor confirmed impaired; states assess on multi-year cycles. 1,925 of those 3,457 fully supporting verdicts (56%) rest on designated uses this site does not report (irrigation, navigation and industrial water supply), with Michigan recording no verdict on fish consumption, recreation, aquatic life and drinking water. They are counted above because the state filed them, and excluded from the impaired share below because that figure compares states.
A large Michigan inventory with a lighter ruled-impairment share
4,307 reported lake-type units put Michigan in the largest third of state registers, while its ruled not-supporting share (35%) sits in the lowest third. Scale and load pull apart on this page.
Data updated 2026-08-17
According to the U.S. Environmental Protection Agency's ATTAINS program, Michigan and the Little River Band of Ottawa Indians reported 4,307 lake-type waterbodies in Michigan in the August 2026 extract. See our methodology for filer attribution and multi-year reporting cycles.
How Michigan's large inventory splits across overall status
Each of the 4,307 lake-type units reported by Michigan and by the Little River Band of Ottawa Indians lands in exactly one overall-status bucket. On a register this large, the bar is an inventory partition, the cause chart and national gauge below answer different questions.
Most-listed impairment causes in Michigan
Waterbodies carrying each listed cause, most first
- Mercury in Fish Tissue
Mercury in Fish Tissue
525 waterbodies
- Perfluorooctane Sulfonate (PFOS) in Fish Tissue
Perfluorooctane Sulfonate (PFOS) in Fish Tissue
271 waterbodies
- Escherichia coli (E. coli)
Escherichia coli (E. coli)
216 waterbodies
- PCBs in Fish Tissue 168
PCBs in Fish Tissue
168 waterbodies
- Dioxin (Including 2,3,7,8-Tcdd) 45
Dioxin (Including 2,3,7,8-Tcdd)
45 waterbodies
What this shows Mercury in Fish Tissue is the most-listed impairment cause in Michigan, on 525 of the lake-type waterbodies reported there. This ranks the cause names filed in Michigan, not distinct pollutants: mercury appears under 2 of them, together listed on 525 waterbodies.
Computed share from EPA ATTAINS filed records, not an official EPA rating or safety grade.
Michigan: 35% of ruled verdicts are not-supporting, against a national share of 53%, 1.5× below the national rate.
Reporting practice
Michigan's definitive-verdict share, by the numbers
Each reporting authority decides how much of the water it files to EPA it actually assesses in a cycle. That decision sets the denominator behind every count on this page.
Michigan holds the 3rd-largest reported lake-type inventory in the country, 4,307 assessment units, carrying a definitive verdict on 54.3% of it. The counts above describe the 2,339 units carrying a verdict, not all 4,307 reported. Michigan has also retired 89 lake-type assessment units, superseded filings that are kept on the site but not counted here.
The states reporting at the nearest rates are Iowa (54.7%) and North Dakota (51.8%).
Assessing more of an inventory is a reporting choice, set by cycle length, monitoring budget and how finely a state splits its waters into units. It is not a measure of water quality, and it is why a raw count from one state does not sit beside a raw count from another. How assessment coverage varies.
Not every unit counted here was assessed by Michigan. 6 of them were filed by a sovereign tribal nation reporting directly to EPA under Clean Water Act section 518, which lets a tribe set and apply its own water quality standards in the same manner as a state: Little River Band of Ottawa Indians (6). Those decisions are theirs, not Michigan's.
Michigan against every comparable state
Share of reported lake-type waterbodies carrying a definitive verdict
54.3% 31st of 47 higher than 16 of 47 states
the 47 comparable states, by definitive-verdict share
Each bar is a band; taller bars hold more states. The dashed line + filled bar mark this entry. Hover or tap any bar for its full count and share, and where it sits relative to this entry.
Source EPA ATTAINS · Reporting cycles 1987–2026
Each bar counts states whose definitive-verdict share falls in that 10-point band. The 47 states shown are those reporting at least 25 lake-type units; a share off a smaller inventory is precision the data does not have.
By size
Largest assessed lakes in Michigan
By assessed acreage as reported in ATTAINS. Acreage is the assessed unit's size, which can differ from a lake's full surface area.
| # | Waterbody | Assessed acres |
|---|---|---|
| 1 | Lake Huron (Michigan Jurisdiction) Not Supporting | 5,815,360 |
| 2 | Lake Michigan South of Frankfort (Michigan Jurisdiction) Not Supporting | 5,665,920 |
| 3 | St. Marys River Not Supporting | 129,983 |
| 4 | Lake St. Clair (Michigan Jurisdiction) Not Supporting | 103,616 |
| 5 | Lake Erie (Michigan Jurisdiction) Not Supporting | 71,680 |
| 6 | Houghton Lake Not Supporting | 20,066 |
| 7 | Torch Lake Not Supporting | 18,713 |
| 8 | Burt Lake Not Supporting | 17,395 |
| 9 | Lake Charlevoix Not Supporting | 17,324 |
| 10 | Mullett Lake Not Supporting | 16,701 |
| 11 | Lake Gogebic Not Supporting | 13,079 |
| 12 | Manistique Lake Not Supporting | 10,336 |
By cause count
Most-listed waterbodies in Michigan
Waterbodies carrying the most listed impairment causes among the lake-type units reported by Michigan and by the Little River Band of Ottawa Indians.
| # | Waterbody | Listed causes |
|---|---|---|
| 1 | Gay Stamp Sands Area of Impact Not Supporting | 9 |
| 2 | St. Louis Impoundment Not Supporting | 8 |
| 3 | Blue Heron Lagoon Not Supporting | 7 |
| 3 | Ford Lake Not Supporting | 7 |
| 3 | Lake Muskoday Not Supporting | 7 |
| 3 | Lake Okonoka Not Supporting | 7 |
| 3 | Lake Tacoma Not Supporting | 7 |
| 8 | Allegan Lake Not Supporting | 6 |
| 8 | Belleville Lake Not Supporting | 6 |
| 8 | Geddes Pond Not Supporting | 6 |
8 of the 10 rows in this table tie on the ranked value: 5 at 7 (rank 3), 3 at 6 (rank 8). Tied rows share a rank and are listed in no meaningful order; where a tie reaches the top the medal is shared, because nothing separates those rows.
Gauge network
Lakes with a daily level record in Michigan
Lakes with a linked USGS gauge and a daily water-level record. Readings are daily-batch snapshots, not real-time.
- Houghton Lake Not Supporting USGS gauge 442400084472801 Level record →
- Mullett Lake Not Supporting USGS gauge 04129950 Level record →
- Lake Gogebic Not Supporting USGS gauge 04035995 Level record →
- Higgins Lake Not Supporting USGS gauge 442805084411001 Level record →
- Otsego Lake Not Supporting USGS gauge 445512084415301 Level record →
- Austin Lake Not Supporting USGS gauge 04097188 Level record →
- Greenwood Reservoir Not Supporting USGS gauge 04057811 Level record →
- Schweitzer Reservoir Not Supporting USGS gauge 04058190 Level record →
States near Michigan's lighter not-supporting load
Two EPA ATTAINS peer sets outside Michigan. The reporting-practice chart above stays on definitive-verdict share; these neighborhoods highlight register-size and not-supporting peers while Michigan's ruled impairment share sits in the lowest third.
Comparable register size
Nearest states by lake-type units on the register (4,307 here).
- New Hampshire · 2,786 units · 1,521 off
- New York · 2,231 units · 2,076 off
- Indiana · 1,588 units · 2,719 off
- Florida · 1,475 units · 2,832 off
Similar not-supporting load
Nearest states by units assessed not supporting a use (807 here). Inventory peers above are omitted.
- Massachusetts · 678 not supporting · 129 off
- New Jersey · 583 not supporting · 224 off
- Wisconsin · 493 not supporting · 314 off
- Illinois · 434 not supporting · 373 off
Peers are nearest-neighbor matches on EPA ATTAINS register size and not-supporting counts among states with at least 25 reported units. Impairment peers skip states already listed in the inventory column so the two link sets stay distinct.
Using this state picture
- Comparisons across states hold on shares, not counts: 54.3% of the inventory reported from Michigan carries a definitive verdict, 31st of 47 comparable states. National rankings
- Fish-consumption verdicts here are assessment decisions. Species-level meal advice comes from the state fish-advisory program. Consumption guide
- Browse every named Michigan waterbody with a populated record. Browse waterbodies
PlainLakes renders state assessment decisions and federal gauge observations without modification.
Figures on this page are computed from the assessment decisions Michigan and the Little River Band of Ottawa Indians reported to EPA's ATTAINS system and from USGS National Water Information System daily values, no number is typed in by an editor. State counts aggregate every lake-type assessment unit reported by Michigan and by the Little River Band of Ottawa Indians, including unnamed units that never receive their own page. See our editorial standards & corrections policy, the methodology behind these numbers, or report a data error. Data current as of 2026-08-17. Primary sources: EPA ATTAINS and USGS National Water Information System.