New York Great Lakes waterbody · state assessment record
Saint Lawrence River, Main Stem (30.80 mi)
Assessment decisions reported by New York to EPA under Clean Water Act sections 303(d) and 305(b), last assessed in the 2022 reporting cycle, a cycle that carries an interim EPA action.
- 30.80
- Miles of shoreline
- Great Lakes Shoreline
- Water type
This waterbody in one line
Saint Lawrence River, Main Stem, a Great Lakes waterbody in New York, 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), a cycle that carries an interim EPA action. 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
- 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.
Saint Lawrence River, Main Stem 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, aquatic life, every determination is Not Supporting. That is a use-by-use reading of the filed record, not a single overall lake grade.
Saint Lawrence River, Main Stem: Category 5, TMDL still owed
Category 5 is the Integrated Report band where a TMDL (or equivalent) is still expected for Saint Lawrence River, Main Stem. 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 Saint Lawrence River, Main Stem 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, New York carries 2,231 filed lake-type waterbodies in the August 2026 extract, and this page renders the assessment record EPA assigned to Saint Lawrence River, Main Stem 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 |
|---|---|---|
| Fishing | Aquatic-life or related | Not Supporting |
| Primary Contact Recreation | Recreation | Insufficient Information |
| Secondary Contact Recreation | Recreation | Insufficient Information |
| Water Supply | Drinking-water supply designation | Insufficient Information |
The record
Listed impairment causes
Causes the state listed as impairing designated uses of this Great Lakes waterbody, with the cycle each was first listed and the Clean Water Act action recorded against it.
| Cause | Affected uses | First listed | Cleanup standing |
|---|---|---|---|
| Dioxin | Fishing Also assessed as meeting: Water Supply, Primary Contact Recreation, Secondary Contact Recreation | 2010 | TMDL priority: Medium |
| Mirex | Fishing Also assessed as meeting: Primary Contact Recreation, Water Supply, Secondary Contact Recreation | 2010 | TMDL priority: Medium |
| Polychlorinated Biphenyls (PCBs) | Fishing Also assessed as meeting: Secondary Contact Recreation, Water Supply, Primary Contact Recreation | 2010 | TMDL priority: Medium |
Reading the record
Where Saint Lawrence River, Main Stem sits among peers
94% of New York's lakes assessed this deeply also had no use supported (the standard result at this depth, not a distinction)
New York ruled definitively on a single designated use at Saint Lawrence River, Main Stem and found it not supported. The dataset shows 434 New York lakes judged to that same depth.
New York's assessed lakes are most often judged on 1 use, 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 | 35 | 16 | 0 | 0 |
| Mixed | Not possible | 1 | 10 | 6 | 0 |
| None supported | 406 (this record) | 86 | 32 | 10 | 0 |
Ringed cell: Saint Lawrence River, Main Stem. Source: EPA ATTAINS, Reporting cycles 1987–2026.
Scale and rank
Saint Lawrence River, Main Stem is one of 2,231 lake-type waterbodies reported to EPA from New York, and one of 428 whose reported record carries enough populated assessment or gauge data for this site to list and index it. New York reports this unit as 30.80 miles of shoreline rather than a surface area, so it is not ranked against the acreage figures elsewhere on this site.
Still unfiled
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 Saint Lawrence River, Main Stem sits nationally
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 Saint Lawrence River, Main Stem. Hover or tap any bar for its full count and share.
In context
New York context
ATTAINS carries 2,231 lake-type waterbodies in New York, 563 assessed as not supporting at least one use and 79 fully supporting. Among the 428 indexed units there, Saint Lawrence River, Main Stem ranks 50th by listed-cause count (3 listed causes) ; it sits in the not-supporting set (563 statewide) . Its listed causes include Polychlorinated Biphenyls (PCBs), which also appears among New York's most-filed impairment causes (led by pH). It also lists Dioxin and Mirex, outside that top-five list.
| Other large assessed lakes in New York | Assessed acres |
|---|---|
| Lake Champlain, Main Lake, Middle Not Supporting | 54,972 |
| Oneida Lake Not Supporting | 51,269 |
| Seneca Lake, Main Lake, Middle Fully Supporting | 40,290 |
| Cayuga Lake, Main Lake, Mid-South Fully Supporting | 33,083 |
| Lake George Not Supporting | 28,523 |
| Great Sacandaga Lake Not Supporting | 24,722 |
Lakes near Saint Lawrence River, Main Stem's cause load
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 NY0901-0015. 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.