Minnesota lake · state assessment record
Mary (188 acres)
Assessment decisions reported by Minnesota to EPA under Clean Water Act sections 303(d) and 305(b), last assessed in the 2022 reporting cycle.
- 188
- Assessed acres
- Lake, Freshwater
- Water type
This waterbody in one line
Mary, a lake in Minnesota, is assessed as not supporting one or more designated uses, with 2 listed impairment causes in the state's most recent Integrated Report cycle (2022). By assessed acreage it sits in the upper quartile by assessed acreage nationally (38,628 lakes); its impairment list is among the longest nationally (2 listed causes vs 23,610 assessed lakes). Aquatic life is assessed as not supporting. Fish consumption is assessed as not supporting.
- Not Supporting
- overall status
- P80
- Assessed size nationally
- P10
- Shorter cause list
- Not Supporting
- aquatic life
Assessment verdicts are the state agency's decisions as reported to EPA ATTAINS; PlainLakes renders them without modification.
A composite of this record's EPA ATTAINS designated-use verdicts, filed impairment count, and assessment currency, weighted and benchmarked against the national corpus of assessed active waterbodies. This is a water-quality standing, not a human-recreation or property-value judgment, and dimensions with no filed verdict drop out rather than count against the score.
Reading Mary's filed record
Paragraphs are selected by this unit's percentiles and use matrix: different lakes lead with different dimensions. Figures are ATTAINS / portal register arithmetic, not advice.
The signature stat: in-state cause rank
Inside Minnesota, cause-list rank is the local separator: Mary is 278 of 1,939 indexed units by listed-cause count, toward the top of that state's filed lists.
The uses disagree
This record splits: Not Supporting on fish consumption, aquatic life, Fully Supporting on recreation. The divergence is inside the designated-use matrix, not a single all-or-nothing label.
Mary: Category 5, TMDL still owed
Category 5 is the Integrated Report band where a TMDL (or equivalent) is still expected for Mary. Read the listed causes and any cleanup actions filed beside them before treating the overall status tile as a finished restoration story.
Large assessed unit
At 187.8 acres, Mary clears the upper tercile of assessed lake-type units with an area on file (7,592 still larger). Size comparisons use the portal's deduplicated lake ranking population, not raw ATTAINS row counts.
Longer than most cause lists
2 listed causes puts this unit above 80% of assessed lake-type records by list length. Treat that as a coding-and-sampling signal: states that split pollutants finely mint longer lists without proving worse water.
According to the U.S. Environmental Protection Agency's ATTAINS program, Minnesota carries 13,176 filed lake-type waterbodies in the August 2026 extract, and this page renders the assessment record EPA assigned to Mary without modification. See our methodology for reporting-unit limits and gauge linking rules.
The record
Designated-use assessments
Fully Supporting and Not Supporting are the state's definitive verdicts; other entries mean the use was not conclusively assessed in this cycle.
| Designated use | Group | Verdict |
|---|---|---|
| Aquatic Consumption | Fish-consumption or fishery | Not Supporting |
| Aquatic Life | Aquatic-life or related | Not Supporting |
| Aquatic Recreation | Recreation | Fully Supporting |
The record
Listed impairment causes
Causes the state listed as impairing designated uses of this lake, with the cycle each was first listed and the Clean Water Act action recorded against it.
| Cause | Affected uses | First listed | Cleanup standing |
|---|---|---|---|
| Mercury in Fish Tissue | Aquatic Consumption | 2020 | TMDL approved |
| Fish Bioassessments | Aquatic Life | 2022 | TMDL priority: Medium |
Reading the record
Where Mary sits among peers
83% of Minnesota's lakes assessed this deeply also came out mixed
Minnesota ruled definitively on 3 designated uses at Mary and found 2 of 3 not supported. The dataset shows 410 Minnesota lakes judged to that same depth.
Minnesota's assessed lakes are most often judged on 1 use; this one was judged on 3.
Computed share from EPA ATTAINS filed records, not an official EPA rating or safety grade.
| 1 | 2 | 3 | 4 | 5+ | |
|---|---|---|---|---|---|
| All supported | 1.4k | 169 | 7 | 1 | 16 |
| Mixed | Not possible | 526 | 341 (this record) | 17 | 10 |
| None supported | 682 | 159 | 62 | 0 | 0 |
Ringed cell: Mary. Source: EPA ATTAINS, Reporting cycles 1987–2026.
Scale and rank
Mary is one of 13,176 lake-type waterbodies reported to EPA from Minnesota, and one of 1,939 whose reported record carries enough populated assessment or gauge data for this site to list and index it. At 188 assessed acres it ranks 7,593rd by assessed size among the 38,628 lakes the dataset carries an area for, counting a state’s repeated filings of one water once, behind 7,592 lakes with a larger one.
In context
Where Mary sits nationally
Assessed size among U.S. lakes
Distribution of assessed acreage across ATTAINS lakes filed with an area, counting a state’s repeated filings of one water once
188 Top 20% larger than 80% of 38,628 lakes
lakes the dataset carries an area for, counting a state’s repeated filings of one water once, bucketed by value
Source EPA ATTAINS · Reporting cycles 1987–2026
Listed causes vs waterbodies carrying a verdict
How many impairment causes U.S. waterbodies with a reported verdict carry
2 Longer than most more listed causes than 80% of 23,610 waterbodies carrying a verdict
named waterbodies carrying a verdict, bucketed by value
Source EPA ATTAINS · Reporting cycles 1987–2026
In both charts each bar is a band and taller bars hold more waterbodies; the dashed line and filled bar mark Mary. Hover or tap any bar for its full count and share.
In context
Minnesota context
ATTAINS carries 13,176 lake-type waterbodies in Minnesota, 1,798 assessed as not supporting at least one use and 1,566 fully supporting. Among the 1,939 indexed units there, Mary ranks 278th by listed-cause count (2 listed causes) and 1,144th by assessed size among the 1,930 with an area filed; it sits in the not-supporting set (1,798 statewide) . Its listed causes include Mercury in Fish Tissue and Fish Bioassessments, which also appear among Minnesota's most-filed impairment causes (led by Mercury in Fish Tissue).
| Other large assessed lakes in Minnesota | Assessed acres |
|---|---|
| Superior Not Supporting | 13,182,720 |
| Lake of the Woods Not Supporting | 301,348 |
| Red (Lower Red) Not reported | 164,699 |
| Lower Red Lake Fully Supporting | 164,689 |
| Mille Lacs Not Supporting | 128,076 |
| Red (Upper Red) Not Supporting | 119,279 |
Peers near Mary's size or cause load
Similar assessed acres
Nearest filed extents (188 acres here).
- LITTLE LAKE - Western Half · 188 acres · MI
- Hoopes Reservoir · 188 acres · DE
- Granite Lake · 188 acres · ID
- Parker Pond · 188 acres · NY
Similar cause load
Nearest listed-cause counts (2 here). Peers already in the acreage column are omitted.
- 12th St. Beach · 2 causes · IL
- 31st St. Beach · 2 causes · IL
- 49th St. Beach · 2 causes · IL
- 57th St. Beach · 2 causes · IL
What to do with this record
- The fish-consumption use is assessed as not supporting. Before eating fish from this lake, check your state fish-advisory program for species-specific meal limits. Consumption status guide
- Impairment listings follow the Clean Water Act 303(d) process; a listing is a regulatory finding, not a closure notice. 303(d) explained
PlainLakes renders state assessment decisions and federal gauge observations without modification. It does not issue advisories.
Assessment decisions on this page are rendered directly from state Integrated Report records in EPA's ATTAINS system; gauge figures are daily-value observations from the USGS National Water Information System, no number is typed in by an editor. Overall status, use verdicts, and causes are the state's reported decisions for assessment unit MN86-0156-00. Counts and percentiles are computed across all lake-type records PlainLakes ingests from ATTAINS. 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.