California lake · state assessment record
Salton Sea
Assessment decisions reported by California to EPA under Clean Water Act sections 303(d) and 305(b), last assessed in the 2026 reporting cycle.
- 233,045
- Assessed acres
- Lake, Saline
- Water type
- -243.9 ft
- Water Surface Elevation (provisional)
This waterbody in one line
Salton Sea, a lake in California, is assessed as not supporting one or more designated uses, with 11 listed impairment causes in the state's most recent Integrated Report cycle (2026). 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 (11 listed causes vs 23,610 assessed lakes). Aquatic life is assessed as not supporting. California assesses commercial and sport fishing as not supported; it reported no verdict on fish consumption itself. A USGS gauge tracks its water surface elevation daily.
- Not Supporting
- overall status
- P100
- Assessed size nationally
- P0
- 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.
Reading Salton Sea'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 Salton Sea nationally is assessed size: 233,045 acres, larger than 100% of the 38,628 lake-type units with an area on file.
Longer than most cause lists
11 listed causes puts this unit above 100% 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.
Every filed use falls short
On the uses this filer ruled on, fish consumption, aquatic life, every determination is Not Supporting. That is a use-by-use reading of the filed record, not a single overall lake grade.
Salton Sea: Category 5, TMDL still owed
Category 5 is the Integrated Report band where a TMDL (or equivalent) is still expected for Salton Sea. 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 Salton Sea 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, California carries 607 filed lake-type waterbodies in the August 2026 extract, and this page renders the assessment record EPA assigned to Salton Sea 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 |
|---|---|---|
| Commercial and Sport Fishing | Fish-consumption or fishery | Not Supporting |
| Warm Freshwater Habitat | Aquatic-life or related | Not Supporting |
| Aquaculture | Other | Insufficient Information |
| Non-Contact Water Recreation | Recreation | Insufficient Information |
| Water Contact Recreation | Recreation | 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 |
|---|---|---|---|
| Arsenic | Commercial and Sport Fishing Also assessed as meeting: Warm Freshwater Habitat | 2010 | TMDL priority: Low |
| Chlorpyrifos | Warm Freshwater Habitat Also assessed as meeting: Commercial and Sport Fishing | 2010 | TMDL priority: Low |
| DDE (Dichlorodiphenyldichloroethylene) | Warm Freshwater Habitat | 2010 | TMDL priority: Low |
| Malathion | Warm Freshwater Habitat | 2010 | TMDL priority: Low |
| Chloride | Warm Freshwater Habitat | 2012 | TMDL priority: Low |
| Cyfluthrin | Warm Freshwater Habitat | 2012 | TMDL priority: Low |
| Cypermethrin | Warm Freshwater Habitat | 2012 | TMDL priority: Low |
| Lambda-Cyhalothrin | Warm Freshwater Habitat | 2012 | TMDL priority: Low |
| DDT (Dichlorodiphenyltrichloroethane) | Commercial and Sport Fishing Also assessed as meeting: Warm Freshwater Habitat | 2014 | TMDL priority: Low |
| Pyrethroids | Warm Freshwater Habitat | 2014 | TMDL priority: Low |
| Imidacloprid | Warm Freshwater Habitat | 2026 | TMDL priority: Low |
Probable sources
California 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 Salton Sea sits among peers
91% of California's lakes assessed this deeply also had no use supported (the standard result at this depth, not a distinction)
California ruled definitively on 2 designated uses at Salton Sea and found none of them supported. The dataset shows 118 California lakes judged to that same depth.
California'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 | 11 | 8 | 0 | 0 | 3 |
| Mixed | Not possible | 3 | 10 | 8 | 8 |
| None supported | 46 | 107 (this record) | 11 | 7 | 2 |
Ringed cell: Salton Sea. Source: EPA ATTAINS, Reporting cycles 1987–2026.
Scale and rank
Salton Sea is one of 607 lake-type waterbodies reported to EPA from California, and one of 195 whose reported record carries enough populated assessment or gauge data for this site to list and index it. At 233,045 assessed acres it ranks 12th 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 11 lakes with a larger one.
Water level
A USGS gauge tracks this lake's water surface elevation daily, and the latest reading is 0.04 ft above the reading 30 days earlier, against a 365-day observed range of 1.1 ft. The state has not yet filed a definitive recreation verdict for this record; that field populates when it reports it in a future Integrated Report cycle.
Water level: 365-day record
Daily water surface elevation values, feet above the National Geodetic Vertical Datum of 1929 (NGVD 29), from USGS gauge 10254005 (Salton Sea Nr Westmorland Ca), shown weekly. Readings are daily-batch snapshots, not real-time conditions.
- Latest reading
- -243.9 ft 0.03999999999999204ft vs 30 days earlier
- 2026-08-15 · Provisional, subject to USGS revision
Water level: 365-day record
Subscribe to water level updates for Salton Sea (RSS)
125 of the 365 daily values in this window (34%) are provisional and subject to USGS revision; USGS has approved this gauge's record through 2026-04-12.
Of the 365 daily values in this record, 1 was estimated by USGS rather than measured. USGS marks these individually; approval and estimation are separate judgements and a value can carry both.
Full gauge record: USGS monitoring location 10254005
In context
Where Salton Sea 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
233,045 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
11 Longer than most more listed causes than 99%+ 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 Salton Sea. Hover or tap any bar for its full count and share.
In context
California context
ATTAINS carries 607 lake-type waterbodies in California, 202 assessed as not supporting at least one use and 22 fully supporting. Among the 195 indexed units there, Salton Sea ranks 1st by listed-cause count (11 listed causes) and 1st by assessed size among the 195 with an area filed; it sits in the not-supporting set (202 statewide) . Its listed causes include DDT (Dichlorodiphenyltrichloroethane), which also appears among California's most-filed impairment causes (led by Mercury). It also lists Arsenic, Chlorpyrifos, DDE (Dichlorodiphenyldichloroethylene), Malathion, Chloride, Cyfluthrin, Cypermethrin, Lambda-Cyhalothrin, Pyrethroids, and Imidacloprid, outside that top-five list.
| Other large assessed lakes in California | Assessed acres |
|---|---|
| Tahoe, Lake Not Supporting | 84,092 |
| Goose Lake (Modoc County) Not reported | 62,385 |
| Honey Lake Not Supporting | 55,526 |
| Klamath River HU, Tule Lake and Lower Klamath Lake National Wildlife Refuge Not Supporting | 48,791 |
| Mono Lake Not Supporting | 45,299 |
| Clear Lake Not Supporting | 39,582 |
Peers near Salton Sea's size or cause load
Similar assessed acres
Nearest filed extents (233,045 acres here).
- Fort Peck Reservoir · 233,296 acres · MT
- Lake Erie Sandusky Basin Open Water (>3m) · 231,494 acres · OH
- Toledo Bend Reservoir-From Texas-Louisiana state line to Toledo Bend Dam · 165,487 acres · LA
- Lake of the Woods (Main) · 301,348 acres · MN
Similar cause load
Nearest listed-cause counts (11 here). Peers already in the acreage column are omitted.
- Branchport Creek · 11 causes · NJ
- Cooper River (Rt 130 to Wallworth gage) · 11 causes · NJ
- Cooper River (Wallworth gage to Evesham Rd) · 11 causes · NJ
- Hackensack R (Amtrak bridge to Rt 3) · 11 causes · NJ
What to do with this record
- The listing here is on a fishery use, not on fish consumption, and this state reported no consumption verdict for this lake. Your state fish-advisory program is the source for whether the catch is safe to eat. Consumption status guide
- Water levels shown are daily snapshots. Seasonal drawdown and datum conventions matter when comparing levels. How to read level data
- 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 CAS7280000019990205133504. 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.