Vermont lake · state assessment record
Halfmoon
Assessment decisions reported by Vermont to EPA under Clean Water Act sections 303(d) and 305(b), last assessed in the 2007 reporting cycle.
- 21
- Assessed acres
- Lake, Freshwater
- Water type
This waterbody in one line
Halfmoon, a lake in Vermont, is assessed as not supporting one or more designated uses, with one listed impairment cause in the state's most recent Integrated Report cycle (2007). By assessed acreage it sits below the national median by assessed acreage (38,628 lakes); its impairment list is among the longest nationally (one listed cause vs 23,610 assessed lakes). Aquatic life is assessed as fully supporting. Fish consumption is assessed as fully supporting.
- Not Supporting
- overall status
- P34
- Assessed size nationally
- P20
- Shorter cause list
- Fully 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 Halfmoon'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 Vermont, cause-list rank is the local separator: Halfmoon is 125 of 712 indexed units by listed-cause count, toward the top of that state's filed lists.
Halfmoon: Category 5, TMDL still owed
Category 5 is the Integrated Report band where a TMDL (or equivalent) is still expected for Halfmoon. Read the listed causes and any cleanup actions filed beside them before treating the overall status tile as a finished restoration story.
Every ruled-on use is fully supporting
The filed use determinations for fish consumption, recreation, aquatic life are all Fully Supporting. Where an overall IR category still flags the unit, look at the cause list and report standing rather than treating the use row as empty.
Overall status: not supporting
The filer's overall status for Halfmoon is Not Supporting. That tile summarizes the assessment unit; the designated-use rows and cause list are the evidence behind it.
Mid-pack assessed size
21 acres lands in the middle tercile of units with an area filed. Acreage is not what distinguishes this record from its peers.
According to the U.S. Environmental Protection Agency's ATTAINS program, Vermont carries 712 filed lake-type waterbodies in the August 2026 extract, and this page renders the assessment record EPA assigned to Halfmoon 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 Biota and Wildlife That May Utilize or Are Present in the Waters | Aquatic-life or related | Fully Supporting |
| Aquatic Habitat to Support Aquatic Biota, Wildlife, or Plant Life | Aquatic-life or related | Fully Supporting |
| Fish Consumption | Fish-consumption or fishery | Fully Supporting |
| The Use of Waters for Boating and Related Recreational Uses | Recreation | Fully Supporting |
| The Use of Waters for Fishing and Related Recreational Uses | Recreation | Fully Supporting |
| The Use of Waters for Swimming and Other Primary Contact Recreation | Recreation | Fully Supporting |
| The Use of Waters for the Enjoyment of Aesthetic Conditions | Other | Not Supporting |
| The Use of Water for Irrigation of Crops and Other Agricultural Uses | Other | Not Assessed |
| The Use of the Water for Public Water Source | Drinking-water supply designation | 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 |
|---|---|---|---|
| Phosphorus, Total | The Use of Waters for the Enjoyment of Aesthetic Conditions | 2018 | 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.
- Phosphorus, Total
- Agriculture (suspected)
Reading the record
Where Halfmoon sits among peers
22% of Vermont's lakes assessed this deeply also came out mixed
Vermont ruled definitively on 7 designated uses at Halfmoon and found 1 of 7 not supported. The dataset shows 700 Vermont lakes judged to that same depth.
Vermont's assessed lakes are most often judged on 5 or more uses, as this one was.
Computed share from EPA ATTAINS filed records, not an official EPA rating or safety grade.
| 1 | 2 | 3 | 4 | 5+ | |
|---|---|---|---|---|---|
| All supported | 0 | 6 | 5 | 0 | 547 |
| Mixed | Not possible | 1 | 0 | 0 | 153 (this record) |
| None supported | 0 | 0 | 0 | 0 | 0 |
Ringed cell: Halfmoon. Source: EPA ATTAINS, Reporting cycles 1987–2026.
Scale and rank
Halfmoon is one of 712 lake-type waterbodies reported to EPA from Vermont, and one of 712 whose reported record carries enough populated assessment or gauge data for this site to list and index it. At 21 assessed acres it ranks 25,669th 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 25,668 lakes with a larger one.
Reported trophic class
Vermont carried the trophic field for this assessment unit and filed it as unclassified, which records that no class was determined rather than that the water is unenriched. What the trophic scale measures.
In context
Where Halfmoon 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
21 Top 66% larger than 34% 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 Halfmoon. Hover or tap any bar for its full count and share.
In context
Vermont context
ATTAINS carries 712 lake-type waterbodies in Vermont, 154 assessed as not supporting at least one use and 558 fully supporting. Among the 712 indexed units there, Halfmoon ranks 125th by listed-cause count (one listed cause) and 339th by assessed size among the 712 with an area filed; it sits in the not-supporting set (154 statewide) . Its listed causes (Phosphorus, Total) sit outside Vermont's top-five list, which is led by Eurasian Water Milfoil, Myriophyllum Spicatum.
| Other large assessed lakes in Vermont | Assessed acres |
|---|---|
| Champ-Northeast Arm Not Supporting | 57,022 |
| Champ-Main Lake Not Supporting | 37,809 |
| Champ-Isle La Motte Not Supporting | 20,962 |
| Champ-Malletts Bay Not Supporting | 12,049 |
| Champ-Port Henry Not Supporting | 8,372 |
| Champ-Missisquoi Bay Not Supporting | 6,398 |
Peers near Halfmoon's size or cause load
Similar assessed acres
Nearest filed extents (21 acres here).
- Anderson Ditch - Unnamed Lake · 21 acres · IN
- Austin Community Lake · 21 acres · MO
- Bakers Meadow Pond · 21 acres · MA
- Barbara, Lake · 21 acres · IN
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 VT07-03L01. 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.