Monroe County, New York · Water Quality Report Card
Lake Ontario
Lake Ontario in Monroe County, New York is not rated for water quality — its monitoring record does not meet the evidence bar. Phosphorus: 126 µg/L. Chlorophyll-a (algae): 17.1 µg/L.
- Mean depth
- ~278 ft est.
- Type
- Eutrophic
Lake Ontario is a productive, nutrient-rich eutrophic lake in Monroe County, New York with an estimated average depth of about 278 feet.
Source: EPA Water Quality Portal sampling records, NYSDEC, last sampled 2023-10-24. Grade methodology: LakeGrade methodology.
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Swimming Safety
Not rated for swimming — there is not enough monitoring data to judge this lake
Water Quality Grade: Not rated
No clarity data. Phosphorus level: 126 µg/L. Chlorophyll-a: 17.1 µg/L. Trophic State Index: 66.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | No data | |
| Phosphorus | 126 µg/L | |
| Chlorophyll-a (Algae) | 17.1 µg/L | |
| Trophic State Index (TSI) | 66 | Eutrophic |
High nutrients, frequent algae, reduced clarity
Lake Details
| Characteristic | Value |
|---|---|
| Average Depth | ~278 ft est. |
Depth marked “est.” is a modeled estimate from HydroLAKES, not a measured survey. New York has not published bathymetry for Lake Ontario.
Where to stay near Lake Ontario
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Fishing Lake Ontario
Location
Nearby Lakes in Monroe County
Explore Lake Ontario across LakeGrade
More New York Lake Rankings
Other Lakes in New York
Eutrophic Lakes in New York
More records, surveys & data sources
EPA Impairment Status
Lake Ontario is officially listed as impaired under Clean Water Act §303(d) in the 2022 EPA reporting cycle (IR category 5).
Causes of impairment
Source: EPA ATTAINS assessment unit NY0301-0016 · Official waterbody report · Matched by proximity (0.98 km)
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.
Where this data comes from
15 measurements from 1 monitoring station, 2023. Retrieved from the EPA Water Quality Portal on 2026-08-02.
Collected and reported by
- USGS New York Water Science Center
USGS-NY15 samples · 2023
Analytical methods
- P, wu, WCA, persulfate CF color
- Plant pigments, sonication & 445
- YSI EXO turbidity sensor, FNU
Monitoring station identifiers (1)
Grade thresholds come from the U.S. EPA National Lakes Assessment 2022 Technical Support Document (EPA 841-R-24-006, Table 6-3), applied by ecoregion. See how grades are calculated.
Data Sources
Water quality data from the EPA Water Quality Portal
Impairment status from EPA ATTAINS 303(d) database
Lake size & watershed from HydroLAKES (HydroSHEDS)
Grade thresholds from the EPA National Lakes Assessment (EPA 841-R-24-006, Table 6-3), applied by ecoregion
Most recent sample: 2023-10-24
Monitoring stations: 1