Washington reservoir · state assessment record
Anderson Lake
Assessment decisions reported by Washington to EPA under Clean Water Act sections 303(d) and 305(b), last assessed in the 2022 reporting cycle.
- 57
- Assessed acres
- Lake / Reservoir / Pond
- Water type
This waterbody in one line
Anderson Lake, a reservoir in Washington, is assessed as not supporting one or more designated uses, with 3 listed impairment causes in the state's most recent Integrated Report cycle (2022). By assessed acreage it sits above the national median by assessed acreage (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
- P58
- 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.
Anderson Lake 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: 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 filed use falls short
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.
Anderson Lake: Category 5, TMDL still owed
Category 5 is the Integrated Report band where a TMDL (or equivalent) is still expected for Anderson Lake. 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 Anderson Lake is Not Supporting. That tile summarizes the assessment unit; the designated-use rows and cause list are the evidence behind it.
Mid-pack inside Washington
Size rank 228 of 385 inside Washington is mid-pack; the national percentile is the better scale comparison for this unit.
According to the U.S. Environmental Protection Agency's ATTAINS program, Washington carries 832 filed lake-type waterbodies in the August 2026 extract, and this page renders the assessment record EPA assigned to Anderson Lake 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 - Core Summer Salmonid Habitat | Aquatic-life or related | Not Supporting |
| Aquatic Life - General | Aquatic-life or related | Not Supporting |
| Recreation - Primary Contact | Recreation | Not 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 |
|---|---|---|---|
| Phosphorus, Total | Aquatic Life - General | 2018 | TMDL priority: Low |
| Harmful Algal Blooms | Recreation - Primary Contact | 2022 | TMDL priority: Low |
| pH | Aquatic Life - Core Summer Salmonid Habitat | 2022 | TMDL priority: Low |
Reading the record
Where Anderson Lake sits among peers
22 of 22 Washington lakes assessed this deeply also had no use supported (every lake judged to this depth, so the outcome does not set this record apart)
Washington ruled definitively on 3 designated uses at Anderson Lake and found none of them supported. The dataset shows 22 Washington lakes judged to that same depth.
Washington's assessed lakes are most often judged on 1 use; this one was judged on 3.
| 1 | 2 | 3 | 4 | 5+ | |
|---|---|---|---|---|---|
| All supported | 0 | 0 | 0 | 0 | 0 |
| Mixed | Not possible | 0 | 0 | 0 | 0 |
| None supported | 272 | 89 | 22 (this record) | 8 | 2 |
Ringed cell: Anderson Lake. Source: EPA ATTAINS, Reporting cycles 1987–2026.
Scale and rank
Anderson Lake is one of 832 lake-type waterbodies reported to EPA from Washington, and one of 385 whose reported record carries enough populated assessment or gauge data for this site to list and index it. At 57 assessed acres it ranks 16,312th 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 16,311 lakes with a larger one.
Open in the register
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 Anderson Lake 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
57 Top 42% larger than 58% 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 Anderson Lake. Hover or tap any bar for its full count and share.
In context
Washington context
ATTAINS carries 832 lake-type waterbodies in Washington, 393 assessed as not supporting at least one use and 0 fully supporting. Among the 385 indexed units there, Anderson Lake ranks 61st by listed-cause count (3 listed causes) and 228th by assessed size among the 385 with an area filed; it sits in the not-supporting set (393 statewide) . Its listed causes include Phosphorus, Total; and pH, which also appear among Washington's most-filed impairment causes (led by Non-Native Aquatic Plants). It also lists Harmful Algal Blooms, outside that top-five list.
| Other large assessed lakes in Washington | Assessed acres |
|---|---|
| Bumping Lake Not Assessed | 1,354 |
| Sullivan Lake Not Supporting | 1,298 |
| Deer Lake Not Supporting | 1,146 |
| Loon Lake Not Supporting | 1,094 |
| American Lake Not Supporting | 1,092 |
| Newman Lake Not Supporting | 1,091 |
Peers near Anderson Lake's size or cause load
Similar assessed acres
Nearest filed extents (57 acres here).
- Beaver · 57 acres · MN
- Hunter Ranch Reservoir · 57 acres · OR
- Warner's Lake · 57 acres · MI
- Camp · 57 acres · MN
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 WA17110019001078_001_001. 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.