Texas reservoir · state assessment record
Sam Rayburn Reservoir (28,238 acres)
Assessment decisions reported by Texas to EPA under Clean Water Act sections 303(d) and 305(b), last assessed in the 2024 reporting cycle.
- 28,238
- Assessed acres
- Reservoir
- Water type
This waterbody in one line
Sam Rayburn Reservoir, a reservoir in Texas, 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 among the largest 1% of assessed lakes nationally (38,628 lakes with a filed area); its impairment list is among the longest nationally (3 listed causes vs 23,610 assessed lakes). Aquatic life is assessed as fully supporting. Fish consumption is assessed as not supporting.
- Not Supporting
- overall status
- P100
- Assessed size nationally
- P5
- 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.
Where Sam Rayburn 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: assessed size
The number that most separates Sam Rayburn Reservoir nationally is assessed size: 28,238 acres, larger than 100% of the 38,628 lake-type units with an area on file.
A split ruling across uses
This record splits: Not Supporting on fish consumption, Fully Supporting on recreation, aquatic life. The divergence is inside the designated-use matrix, not a single all-or-nothing label.
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.
Sam Rayburn Reservoir: Category 5, TMDL still owed
Category 5 is the Integrated Report band where a TMDL (or equivalent) is still expected for Sam Rayburn 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 Sam Rayburn Reservoir is Not Supporting. That tile summarizes the assessment unit; the designated-use rows and cause list are the evidence behind it.
According to the U.S. Environmental Protection Agency's ATTAINS program, Texas carries 489 filed lake-type waterbodies in the August 2026 extract, and this page renders the assessment record EPA assigned to Sam Rayburn 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 Life Use | Aquatic-life or related | Fully Supporting |
| Domestic Water Supply - Public Water Supply | Drinking-water supply designation | Fully Supporting |
| Fish Consumption Use | Fish-consumption or fishery | Not Supporting |
| General Use | Other | Not Supporting |
| Recreation Use | Recreation | Fully Supporting |
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 - Fish Consumption Advisory | Fish Consumption Use | 1996 | TMDL priority: Low |
| Dioxin - Fish Consumption Advisory | Fish Consumption Use | 2014 | TMDL priority: Low |
| Algae | General Use | 2022 | 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 - Fish Consumption Advisory
- Atmospheric Deposition - Toxics (suspected)
- Dioxin - Fish Consumption Advisory
- Industrial Point Source Discharge (suspected) Upstream Source (suspected)
- Algae
- Non-Point Source (suspected) Upstream Source (suspected)
Texas also recorded the source of at least one listing here as unknown, including for Mercury - Fish Consumption Advisory.
Reading the record
Where Sam Rayburn Reservoir sits among peers
49% of Texas's lakes assessed this deeply also came out mixed
Texas ruled definitively on 5 designated uses at Sam Rayburn Reservoir and found 2 of 5 not supported. The dataset shows 67 Texas lakes judged to that same depth.
Texas's assessed lakes are most often judged on 4 uses; this one was judged on 5.
Computed share from EPA ATTAINS filed records, not an official EPA rating or safety grade.
| 1 | 2 | 3 | 4 | 5+ | |
|---|---|---|---|---|---|
| All supported | 7 | 76 | 42 | 149 | 34 |
| Mixed | Not possible | 18 | 19 | 38 | 33 (this record) |
| None supported | 14 | 3 | 0 | 0 | 0 |
Ringed cell: Sam Rayburn Reservoir. Source: EPA ATTAINS, Reporting cycles 1987–2026.
Scale and rank
Sam Rayburn Reservoir is one of 489 lake-type waterbodies reported to EPA from Texas, and one of 323 whose reported record carries enough populated assessment or gauge data for this site to list and index it. At 28,238 assessed acres it ranks 110th 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 109 lakes with a larger one.
In context
Where Sam Rayburn 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
28,238 Top 1% larger than 99%+ 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 Sam Rayburn Reservoir. Hover or tap any bar for its full count and share.
In context
Texas context
ATTAINS carries 489 lake-type waterbodies in Texas, 125 assessed as not supporting at least one use and 331 fully supporting. Among the 323 indexed units there, Sam Rayburn Reservoir ranks 3rd by listed-cause count (3 listed causes) and 4th by assessed size among the 323 with an area filed; it sits in the not-supporting set (125 statewide) . Its listed causes include Mercury - Fish Consumption Advisory, Dioxin - Fish Consumption Advisory, and Algae, which also appear among Texas's most-filed impairment causes (led by Algae).
| Other large assessed lakes in Texas | Assessed acres |
|---|---|
| Lake Texoma Fully Supporting | 49,400 |
| Toledo Bend Reservoir Not Supporting | 41,046 |
| International Falcon Reservoir Fully Supporting | 36,817 |
| International Amistad Reservoir Fully Supporting | 21,328 |
| Lake Livingston Not Supporting | 18,238 |
| Caddo Lake Not Assessed | 16,750 |
Peers near Sam Rayburn Reservoir's size or cause load
Similar assessed acres
Nearest filed extents (28,238 acres here).
- Lake George · 28,523 acres · NY
- Lake Koocanusa · 28,875 acres · MT
- Old Hickory Reservoir · 27,439 acres · TN
- Klamath River HU, Lost River HA, Clear Lake, Boles HSAs · 29,220 acres · CA
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
- The fish-consumption use is assessed as not supporting. Before eating fish from this reservoir, 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 TX-0610_02. 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.