Cossayuna Lake
Washington County, New YorkView mapDirections
Not Rated: one monitoring station are on record, but they measured water clarity only. LakeQuality’s A–F method grades total phosphorus, total nitrogen, chlorophyll-a, and turbidity; clarity is shown, not scored.
- Impaired · Nutrients (phosphorus, nitrogen)
- 48 ft max depth
- Public access
- Limited data
Cossayuna Lake in Washington County, New York is not rated for water quality — its monitoring record does not meet the evidence bar. Water clarity: 8.8 ft visibility.
- Clarity
- 8.8 ft
- Max depth
- ~48 ft est.
- Public access
- Yes
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Stays near Cossayuna Lake
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Watch Cossayuna Lake’s letter
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Why Cossayuna Lake has no grade
Cossayuna Lake has monitoring on record from one station, but only water clarity was measured. LakeQuality’s A–F letter uses total phosphorus, total nitrogen, chlorophyll-a, and turbidity against EPA National Lakes Assessment condition classes. With none of those grading measurements on record, Cossayuna Lake is Not Rated — not an F. Its 8.8-foot median from 8 readings collected 2020 is still shown as clarity, but clarity alone cannot earn a letter.
Not Rated is EPA Integrated Reporting Category 3 — insufficient information. Everything below that has been measured is still reported on this page.
Sampling is run by NYSDEC and volunteer programs, and published through the EPA Water Quality Portal. Read the full grading methodology.
Cossayuna Lake is a lake in Washington County, New York with an estimated average depth of about 48 feet. Limited fish-species data available. Public access is available with 1 public boat landing.
Source: EPA Water Quality Portal sampling records, NYSDEC, last sampled 2020-09-22. Grade methodology: LakeQuality methodology.
What Cossayuna Lake is good for
From access and monitoring records, not editorial picks.
- Boat launch1 documented ramp
Swimming Safety
Not ratedLimited data
The letter is not a swimming clearance. Cossayuna Lake is listed impaired under Clean Water Act §303(d) (IR 4A) for nutrients (phosphorus, nitrogen). Check local advisories before you swim.
Water quality measurements for Cossayuna Lake
These readings exist but are not enough for an A–F grade — see why.
Moderate clarity, visible to about 8.8 ft. TSI 46.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 8.8 ft | Not graded |
| Phosphorus | No recent samples | |
| Chlorophyll-a (Algae) | No recent samples | |
| Trophic State Index (TSI) | 46 | Mesotrophic |
Moderate nutrients, good water quality
Lake Details
| Characteristic | Value |
|---|---|
| Maximum Depth | ~48 ft est. |
| Average Depth | ~37 ft est. |
| Public Access | Yes |
Depth marked “est.” is a modeled maximum from GLOBathy (Khazaei et al. 2022, CC0), not a measured survey. New York has not published bathymetry for Cossayuna Lake.
Lake Size & Watershed
Size, shoreline, and watershed area from HydroLAKES (HydroSHEDS). Mean depth here is modelled, not surveyed — HydroLAKES v1.0 estimates lake depth from surrounding terrain rather than from soundings. Treat it as an approximation, and prefer a state bathymetric survey where one exists.
Recreation & Access
- Cossayuna LakePublic
Named access points in the USGS National Boat Ramps inventory, within about 3 miles. More lakes with boat ramps
Fishing Cossayuna Lake
EPA Impairment Status
Cossayuna Lake is officially listed as impaired under Clean Water Act §303(d) in the 2022 EPA reporting cycle (IR category 4A).
Causes of impairment
A Total Maximum Daily Load (TMDL) plan has been approved.
Source: EPA ATTAINS assessment unit NY1103-0002 · Official waterbody report
Regulated Pollution Sources Nearby
2 EPA-permitted facilities operate within about 5 miles of Cossayuna Lake under Clean Water Act (NPDES) discharge permits.
- Argyle Central High SchoolArgyle · 3.9 mi away · NPDES NY0023663
- Covidien LpArgyle · 4.7 mi away · NPDES NY0110141
Facilities permitted to discharge under the Clean Water Act within ~5 miles; proximity does not by itself mean a facility affects this lake. Source: EPA ECHO (ICIS-NPDES), as of 2026-07.
Graded lakes near Cossayuna Lake
Cossayuna Lake has no grade, but these lakes within a short drive do.
Nearby Lakes in Washington County
Frequently asked questions about Cossayuna Lake
Where is Cossayuna Lake?
- Cossayuna Lake is a lake in Washington County, New York. LakeQuality has not rated this lake (UNRATED) — the only measurement available is water clarity, which is not a water-quality indicator on its own — EPA's National Lakes Assessment does not grade clarity.
What is the water quality grade for Cossayuna Lake?
- Cossayuna Lake in Washington County, New York is not rated for water quality — its monitoring record does not meet the evidence bar. Water clarity: 8.8 ft visibility.
Is Cossayuna Lake safe to swim in?
- The letter is not a swimming clearance. Cossayuna Lake is listed impaired under Clean Water Act §303(d) (IR 4A) for nutrients (phosphorus, nitrogen). Check local advisories before you swim.
How deep is Cossayuna Lake?
- No published bathymetric survey covers Cossayuna Lake, so its depth has not been measured. The HydroLAKES global model estimates an average depth of about 48 feet, but that is a modelled estimate derived from surrounding terrain rather than a measurement on the water, so treat it as approximate.
Are there boat ramps on Cossayuna Lake?
- Cossayuna Lake has 1 documented boat landing in the USGS National Boat Ramps inventory. Named access points include Cossayuna Lake. Public access is listed as yes.
Explore Cossayuna Lake across LakeQuality
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Where this data comes from
8 measurements from 1 monitoring station, 2020. Retrieved from the EPA Water Quality Portal on 2026-08-02.
Collected and reported by
- North American Lake Management Society
NALMS8 samples · 2020
Monitoring station identifiers (1)
Grade thresholds from the EPA National Lakes Assessment (EPA 841-R-24-006, Table 6-3), applied by ecoregion. See how grades are calculated and data sources.
Other records on this page
Impairment status from EPA ATTAINS 303(d) database
Regulated discharger data from EPA ECHO (ICIS-NPDES)
Lake size & watershed from HydroLAKES (HydroSHEDS)
Named boat-access points from the USGS National Boat Ramps inventory