Utah lake · state assessment record
Mill Meadow Reservoir
Assessment decisions reported by Utah to EPA under Clean Water Act sections 303(d) and 305(b), last assessed in the 2024 reporting cycle.
- 160
- Assessed acres
- Lake, Freshwater
- Water type
This waterbody in one line
Mill Meadow Reservoir, a lake in Utah, is assessed as not supporting one or more designated uses, with 3 listed impairment causes in the state's most recent Integrated Report cycle (2024). By assessed acreage it sits in the upper quartile 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.
- Not Supporting
- overall status
- P78
- 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.
Where Mill Meadow Reservoir 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: cause-list length
The standout filed fact is cause-list length: 3 listed impairment causes, a longer list than 90% of assessed lake-type units (n=23,610). List length tracks how states sample and code, not a severity score.
Every ruled-on use is not supporting
On the uses this filer ruled on, recreation, aquatic life, every determination is Not Supporting. That is a use-by-use reading of the filed record, not a single overall lake grade.
Mill Meadow Reservoir: Category 5, TMDL still owed
Category 5 is the Integrated Report band where a TMDL (or equivalent) is still expected for Mill Meadow 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 Mill Meadow Reservoir is Not Supporting. That tile summarizes the assessment unit; the designated-use rows and cause list are the evidence behind it.
Large assessed unit
At 160.4 acres, Mill Meadow Reservoir clears the upper tercile of assessed lake-type units with an area on file (8,512 still larger). Size comparisons use the portal's deduplicated lake ranking population, not raw ATTAINS row counts.
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 Mill Meadow 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 |
|---|---|---|
| Aquatic Wildlife (Cold Water) | Aquatic-life or related | Not Supporting |
| Recreation and Aesthetics (Infrequent Primary Contact) | Recreation | Not Supporting |
| Agricultural | Other | 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 |
|---|---|---|---|
| Phosphorus, Total | Aquatic Wildlife (Cold Water) | 1998 | TMDL approved |
| Harmful Algal Blooms | Recreation and Aesthetics (Infrequent Primary Contact) | 2024 | TMDL priority: Low |
| Eutrophication | Aquatic Wildlife (Cold Water) | 2026 | 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 Mill Meadow Reservoir sits among peers
3% of Utah's lakes assessed this deeply also had no use supported
Utah ruled definitively on 2 designated uses at Mill Meadow Reservoir and found none of them 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 | 21 | 9 | 1 |
| None supported | 14 | 2 (this record) | 1 | 0 | 0 |
Ringed cell: Mill Meadow Reservoir. Source: EPA ATTAINS, Reporting cycles 1987–2026.
Scale and rank
Mill Meadow 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 160 assessed acres it ranks 8,513th 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 8,512 lakes with a larger one.
Awaiting a filing
The state has not yet filed a definitive fish-consumption verdict for this record; that field populates when it reports it in a future Integrated Report cycle.
In context
Where Mill Meadow 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
160 Top 22% larger than 78% 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 Mill Meadow 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, Mill Meadow Reservoir ranks 27th by listed-cause count (3 listed causes) and 44th by assessed size among the 84 with an area filed; it sits in the not-supporting set (77 statewide) . Its listed causes include Phosphorus, Total; and Harmful Algal Blooms, which also appear among Utah's most-filed impairment causes (led by pH). It also lists Eutrophication, outside that top-five list.
| 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 Mill Meadow Reservoir's size or cause load
Similar assessed acres
Nearest filed extents (160 acres here).
- Dutch · 160 acres · MN
- Rancho Seco Lake (Sacramento County) · 160 acres · CA
- Little Portage Lake · 160 acres · WI
- Lost Lake · 160 acres · WI
Similar cause load
Nearest listed-cause counts (3 here). Peers already in the acreage column are omitted.
- 67th St. Beach · 3 causes · IL
- Abiquiu Reservoir · 3 causes · NM
- Absecon Creek (AC Reserviors) (gage to SB) · 3 causes · NJ
- Absecon Creek (below gage) · 3 causes · NJ
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-14070003-015_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.