Tennessee reservoir · state assessment record
Chilhowee Reservoir
Assessment decisions reported by Tennessee to EPA under Clean Water Act sections 303(d) and 305(b), last assessed in the 2022 reporting cycle.
- 1,749
- Assessed acres
- Lake / Reservoir / Pond
- Water type
This waterbody in one line
Chilhowee Reservoir, a reservoir in Tennessee, is assessed as not supporting one or more designated uses, with one listed impairment cause in the state's most recent Integrated Report cycle (2022). By assessed acreage it sits among the largest 5% by assessed acreage nationally (38,628 lakes); its impairment list is among the longest nationally (one listed cause vs 23,610 assessed lakes).
- Not Supporting
- overall status
- P96
- Assessed size nationally
- P20
- Shorter cause list
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 Chilhowee Reservoir'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: assessed size
The number that most separates Chilhowee Reservoir nationally is assessed size: 1,749 acres, larger than 96% of the 38,628 lake-type units with an area on file.
Every filed use falls short
On the uses this filer ruled on, recreation, every determination is Not Supporting. That is a use-by-use reading of the filed record, not a single overall lake grade.
Chilhowee Reservoir: Category 5, TMDL still owed
Category 5 is the Integrated Report band where a TMDL (or equivalent) is still expected for Chilhowee Reservoir. Read the listed causes and any cleanup actions filed beside them before treating the overall status tile as a finished restoration story.
Overall status: not supporting
The filer's overall status for Chilhowee Reservoir is Not Supporting. That tile summarizes the assessment unit; the designated-use rows and cause list are the evidence behind it.
Typical cause-list length
1 listed cause is a middle-tercile list length among assessed lake-type units. Look to IR category and use outcomes for the distinctive reading.
According to the U.S. Environmental Protection Agency's ATTAINS program, Tennessee carries 117 filed lake-type waterbodies in the August 2026 extract, and this page renders the assessment record EPA assigned to Chilhowee Reservoir 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. Tennessee filed its own confidence on the one definitive verdict 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 |
|---|---|---|
| Recreation | Recreation | Not Supporting Filer confidence: Good |
| Domestic Water Supply | Drinking-water supply designation | Not Assessed |
| Fish and Aquatic Life | Aquatic-life or related | Not Assessed |
| Irrigation | Other | Not Assessed |
| Livestock Watering and Wildlife | Other | Not Assessed |
The record
Listed impairment causes
Causes the state listed as impairing designated uses of this reservoir, 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 | Recreation | 2026 | TMDL priority: Low |
Probable sources named by the state
Each source below is listed under the cause the state filed it against, and carries the word the state filed with it — confirmed, or suspected.
- Mercury in Fish Tissue
- Atmospheric Deposition (suspected)
Reading the record
Where Chilhowee Reservoir sits among peers
10 of 10 Tennessee lakes assessed this deeply also had no use supported (every lake judged to this depth, so the outcome does not set this record apart)
Tennessee ruled definitively on a single designated use at Chilhowee Reservoir and found it not supported. The dataset shows 10 Tennessee lakes judged to that same depth.
Tennessee's assessed lakes are most often judged on 5 or more uses; this one was judged on 1.
| 1 | 2 | 3 | 4 | 5+ | |
|---|---|---|---|---|---|
| All supported | 0 | 0 | 0 | 5 | 13 |
| Mixed | Not possible | 0 | 3 | 11 | 31 |
| None supported | 10 (this record) | 2 | 1 | 0 | 0 |
Ringed cell: Chilhowee Reservoir. Source: EPA ATTAINS, Reporting cycles 1987–2026.
Scale and rank
Chilhowee Reservoir is one of 117 lake-type waterbodies reported to EPA from Tennessee, and one of 73 whose reported record carries enough populated assessment or gauge data for this site to list and index it. At 1,749 assessed acres it ranks 1,508th 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 1,507 lakes with a larger one.
Open in the register
The state has not yet filed a definitive fish-consumption verdict and a definitive aquatic-life verdict for this record; those fields populate when it reports them in a future Integrated Report cycle.
In context
Where Chilhowee Reservoir 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
1,749 Top 4% larger than 96% 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
1 Longer than most more listed causes than 49% 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 Chilhowee Reservoir. Hover or tap any bar for its full count and share.
In context
Tennessee context
ATTAINS carries 117 lake-type waterbodies in Tennessee, 60 assessed as not supporting at least one use and 16 fully supporting. Among the 73 indexed units there, Chilhowee Reservoir ranks 45th by listed-cause count (one listed cause) and 38th by assessed size among the 73 with an area filed; it sits in the not-supporting set (60 statewide) . Its listed causes include Mercury in Fish Tissue, which also appears among Tennessee's most-filed impairment causes (led by Mercury in Fish Tissue).
| Other large assessed lakes in Tennessee | Assessed acres |
|---|---|
| Kentucky Reservoir Fully Supporting | 99,500 |
| Chickamauga Reservoir Fully Supporting | 35,400 |
| Watts Bar Reservoir Not Supporting | 34,075 |
| Douglas Reservoir Fully Supporting | 30,400 |
| Old Hickory Reservoir Fully Supporting | 27,439 |
| Cherokee Reservoir Not Supporting | 25,964 |
Peers near Chilhowee Reservoir's size or cause load
Similar assessed acres
Nearest filed extents (1,749 acres here).
- Newton · 1,750 acres · IL
- Tombigbee River (Demopolis Lake) · 1,750 acres · AL
- Cross Lake Reservoir (Main Basin) · 1,751 acres · MN
- Moore Reservoir · 1,747 acres · NH
Similar cause load
Nearest listed-cause counts (1 here). Peers already in the acreage column are omitted.
- Aaron · 1 causes · MN
- Aaron River Reservoir · 1 causes · MA
- Abbotts Creek (including Lexington-Thomasville Water Supply Reservoir at normal reservoir elevation, Tom-A-Lex Lake) · 1 causes · NC
- Abeniki Lake · 1 causes · NH
What to do with this record
- Assessment verdicts are cycle-based, not real-time. For fish-consumption decisions, your state advisory program is the binding source. 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 TN06010204CHILHOWEE_1000. 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.