Illinois lake · state assessment record
Vermilion
Assessment decisions reported by Illinois to EPA under Clean Water Act sections 303(d) and 305(b), last assessed in the 2018 reporting cycle.
- 878
- Assessed acres
- Lake, Freshwater
- Water type
- Eutrophic
- Reported trophic class
This waterbody in one line
Vermilion, a lake in Illinois, is assessed as not supporting one or more designated uses, with 3 listed impairment causes in the state's most recent Integrated Report cycle (2018). By assessed acreage it sits among the largest 10% by assessed acreage nationally (38,628 lakes); its impairment list is among the longest nationally (3 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
- P94
- Assessed size nationally
- P5
- 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 Vermilion'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: monitoring lag
The signature tension is currency: the reporting cycle is 2018 while monitoring evidence runs through 2010, a 8-year gap. Cycle year and last-monitored year move independently in ATTAINS; this page shows both.
Large assessed unit
At 878 acres, Vermilion clears the upper tercile of assessed lake-type units with an area on file (2,473 still larger). Size comparisons use the portal's deduplicated lake ranking population, not raw ATTAINS row counts.
Every filed use falls short
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.
Longer than most cause lists
3 listed causes puts this unit above 90% 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.
Vermilion: Category 5, TMDL still owed
Category 5 is the Integrated Report band where a TMDL (or equivalent) is still expected for Vermilion. Read the listed causes and any cleanup actions filed beside them before treating the overall status tile as a finished restoration story.
According to the U.S. Environmental Protection Agency's ATTAINS program, Illinois carries 783 filed lake-type waterbodies in the August 2026 extract, and this page renders the assessment record EPA assigned to Vermilion 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. Monitoring behind at least one of these designated-use verdicts ran through 2010, as Illinois filed it. Illinois filed its own confidence on the 3 definitive verdicts it rated: Good. That rating is the filer's, in EPA's own field, and EPA publishes no definition of the four words it offers.
| Designated use | Group | Verdict |
|---|---|---|
| Aesthetic Quality | Other | Not Supporting Filer confidence: Good |
| Aquatic Life | Aquatic-life or related | Not Supporting Filer confidence: Good |
| Fish Consumption | Fish-consumption or fishery | Not Supporting Filer confidence: Good |
| Primary Contact | Recreation | Not Assessed |
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 | Fish Consumption | 2008 | TMDL priority: Medium |
| Phosphorus, Total | Aquatic Life, Aesthetic Quality | 2008 | TMDL approved |
| Dissolved Oxygen | Aquatic Life | 2014 | TMDL priority: Medium |
Reading the record
How current is Vermilion's evidence?
8 years between the 2018 reporting cycle and monitoring through 2010
Monitoring behind at least one of these designated-use verdicts ran through 2010, as Illinois filed it.
The cycle is when the state reported; the monitoring year, where filed, is when it measured. How to read assessment currency.
Scale and rank
Vermilion is one of 783 lake-type waterbodies reported to EPA from Illinois, and one of 439 whose reported record carries enough populated assessment or gauge data for this site to list and index it. At 878 assessed acres it ranks 2,474th 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 2,473 lakes with a larger one.
Still unfiled
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.
Reported trophic class
Eutrophic is the trophic class the filing agency reported to EPA ATTAINS for this assessment unit. It describes nutrient enrichment, not whether the water is safe, and it is not a PlainLakes inference. What the trophic scale measures.
In context
Where Vermilion 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
878 Top 6% larger than 94% 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
3 Longer than most more listed causes than 90% 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 Vermilion. Hover or tap any bar for its full count and share.
In context
Illinois context
ATTAINS carries 783 lake-type waterbodies in Illinois, 434 assessed as not supporting at least one use and 63 fully supporting. Among the 439 indexed units there, Vermilion ranks 81st by listed-cause count (3 listed causes) and 35th by assessed size among the 388 with an area filed; it sits in the not-supporting set (434 statewide) . Its listed causes include Mercury; and Phosphorus, Total, which also appear among Illinois's most-filed impairment causes (led by Phosphorus, Total). It also lists Dissolved Oxygen, outside that top-five list.
| Other large assessed lakes in Illinois | Assessed acres |
|---|---|
| Lake Michigan Nearshore Not Supporting | 125,440 |
| Carlyle Not Supporting | 24,580 |
| Rend Not Supporting | 18,900 |
| Shelbyville Not Supporting | 11,000 |
| Crab Orchard Not Supporting | 6,965 |
| Clinton Not Supporting | 4,895 |
Peers near Vermilion's size or cause load
Similar assessed acres
Nearest filed extents (878 acres here).
- NEUSE RIVER (Falls Lake below normal pool elevation) · 878 acres · NC
- Quemehoning Reservoir-05010007001427 · 878 acres · PA
- Cedar · 879 acres · MN
- Upper Sakatah · 879 acres · MN
Similar cause load
Nearest listed-cause counts (3 here). Peers already in the acreage column are omitted.
- Abiquiu Reservoir · 3 causes · NM
- Absecon Creek (AC Reserviors) (gage to SB) · 3 causes · NJ
- Absecon Creek (below gage) · 3 causes · NJ
- Agate Reservoir · 3 causes · OR
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 IL_RBD. 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.