Utah lake · state assessment record
Silver Lake Flat Reservoir
Assessment decisions reported by Utah to EPA under Clean Water Act sections 303(d) and 305(b), last assessed in the 2026 reporting cycle.
- 33
- Assessed acres
- Lake, Freshwater
- Water type
This waterbody in one line
Silver Lake Flat Reservoir, a lake in Utah, is assessed as not supporting one or more designated uses, with one listed impairment cause in the state's most recent Integrated Report cycle (2026). 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 not supporting.
- Not Supporting
- overall status
- P44
- Assessed size nationally
- P20
- 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.
Silver Lake Flat Reservoir against the ATTAINS 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: in-state cause rank
Inside Utah, this unit sits toward the short-list end: cause-list rank 71 of 84 indexed units.
Every filed use falls short
On the uses this filer ruled on, aquatic life, every determination is Not Supporting. That is a use-by-use reading of the filed record, not a single overall lake grade.
Silver Lake Flat Reservoir: Category 5, TMDL still owed
Category 5 is the Integrated Report band where a TMDL (or equivalent) is still expected for Silver Lake Flat 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 Silver Lake Flat Reservoir is Not Supporting. That tile summarizes the assessment unit; the designated-use rows and cause list are the evidence behind it.
Small within Utah
State size rank 70 of 84 puts Silver Lake Flat Reservoir toward the small end of Utah's indexed lake-type units with an area.
According to the U.S. Environmental Protection Agency's ATTAINS program, Utah carries 143 filed lake-type waterbodies in the August 2026 extract, and this page renders the assessment record EPA assigned to Silver Lake Flat 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.
| Designated use | Group | Verdict |
|---|---|---|
| Agricultural | Other | Fully Supporting |
| Aquatic Wildlife (Cold Water) | Aquatic-life or related | Not Supporting |
| Recreation and Aesthetics (Infrequent 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 |
|---|---|---|---|
| Dissolved Oxygen | Aquatic Wildlife (Cold Water) | 2020 | TMDL priority: Low |
Probable sources
Utah listed the source of the impairment as unknown. That is the state's own filed value, not a gap in this record: the cause has been identified, the origin has not.
Reading the record
Where Silver Lake Flat Reservoir sits among peers
50% of Utah's lakes assessed this deeply also came out mixed
Utah ruled definitively on 2 designated uses at Silver Lake Flat Reservoir and found 1 of 2 not supported. The dataset shows 58 Utah lakes judged to that same depth.
Utah's assessed lakes are most often judged on 2 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 | 28 | 27 | 2 | 3 | 0 |
| Mixed | Not possible | 29 (this record) | 21 | 9 | 1 |
| None supported | 14 | 2 | 1 | 0 | 0 |
Ringed cell: Silver Lake Flat Reservoir. Source: EPA ATTAINS, Reporting cycles 1987–2026.
Scale and rank
Silver Lake Flat Reservoir is one of 143 lake-type waterbodies reported to EPA from Utah, and one of 84 whose reported record carries enough populated assessment or gauge data for this site to list and index it. At 33 assessed acres it ranks 21,520th 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 21,519 lakes with a larger one.
Open in the register
The state has not yet filed a definitive fish-consumption verdict and a definitive recreation verdict for this record; those fields populate when it reports them in a future Integrated Report cycle.
In context
Where Silver Lake Flat 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
33 Top 56% larger than 44% 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 Silver Lake Flat Reservoir. Hover or tap any bar for its full count and share.
In context
Utah context
ATTAINS carries 143 lake-type waterbodies in Utah, 77 assessed as not supporting at least one use and 60 fully supporting. Among the 84 indexed units there, Silver Lake Flat Reservoir ranks 71st by listed-cause count (one listed cause) and 70th by assessed size among the 84 with an area filed; it sits in the not-supporting set (77 statewide) . Its listed causes include Dissolved Oxygen, which also appears among Utah's most-filed impairment causes (led by pH).
| Other large assessed lakes in Utah | Assessed acres |
|---|---|
| Gilbert Bay Fully Supporting | 559,424 |
| Gunnison Bay Not Assessed | 384,588 |
| Lake Powell Fully Supporting | 149,885 |
| Utah Lake other than Provo Bay Not Supporting | 87,984 |
| Farmington Bay Not Assessed | 77,243 |
| Bear River Bay Not Assessed | 71,681 |
Peers near Silver Lake Flat Reservoir's size or cause load
Similar assessed acres
Nearest filed extents (33 acres here).
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 UT-L-16020201-006_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.