Minnesota lake · state assessment record
Waconia
Assessment decisions reported by Minnesota to EPA under Clean Water Act sections 303(d) and 305(b), last assessed in the 2017 reporting cycle.
- 3,066
- Assessed acres
- Lake, Freshwater
- Water type
This waterbody in one line
Waconia, 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 (2017). By assessed acreage it sits among the largest 5% 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
- P98
- 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.
Where Waconia stands in the filed register
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: assessed size
The number that most separates Waconia nationally is assessed size: 3,066 acres, larger than 98% of the 38,628 lake-type units with an area on file.
Every ruled-on use is not supporting
On the uses this filer ruled on, fish consumption, aquatic life, every determination is Not Supporting. That is a use-by-use reading of the filed record, not a single overall lake grade.
Waconia: Category 5, TMDL still owed
Category 5 is the Integrated Report band where a TMDL (or equivalent) is still expected for Waconia. Read the listed causes and any cleanup actions filed beside them before treating the overall status tile as a finished restoration story.
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.
Overall status: not supporting
The filer's overall status for Waconia is Not Supporting. That tile summarizes the assessment unit; the designated-use rows and cause list are the evidence behind it.
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 Waconia 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 | Insufficient Information |
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 | 1998 | TMDL approved |
| Fish Bioassessments | Aquatic Life | 2018 | TMDL priority: Medium |
Reading the record
Where Waconia sits among peers
19% of Minnesota's lakes assessed this deeply also had no use supported
Minnesota ruled definitively on 2 designated uses at Waconia and found none of them supported. The dataset shows 854 Minnesota lakes judged to that same depth.
Minnesota's assessed lakes are most often judged on 1 use; this one was judged on 2.
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 | 17 | 10 |
| None supported | 682 | 159 (this record) | 62 | 0 | 0 |
Ringed cell: Waconia. Source: EPA ATTAINS, Reporting cycles 1987–2026.
Scale and rank
Waconia 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 3,066 assessed acres it ranks 980th 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 979 lakes with a larger one.
Not yet on record
The state has not yet filed a definitive recreation verdict for this record; that field populates when it reports it in a future Integrated Report cycle.
In context
Where Waconia 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
3,066 Top 2% larger than 98% 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 Waconia. 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, Waconia ranks 88th by listed-cause count (2 listed causes) and 72nd 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 Waconia's size or cause load
Similar assessed acres
Nearest filed extents (3,066 acres here).
- Lake Ray Hubbard · 3,069 acres · TX
- First Connecticut Lake · 3,063 acres · NH
- Conowingo Reservoir · 3,070 acres · MD
- Lake Gaston · 3,072 acres · VA
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 MN10-0059-00. 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.