Lk Ontario Lake
Monroe County, WisconsinEutrophic
Lk Ontario Lake is a productive, nutrient-rich eutrophic lake in Monroe County, NY. Water quality is graded D based on 2 sampling years through 2023. Compared to the 4 other monitored lakes in Monroe County, Lk Ontario Lake ranks #4 for water quality.
Source: EPA Water Quality Portal sampling records, local state DNR records, last sampled 2023-10-24. Grade methodology: LakeGrade methodology.
Swimming Safety
Swimming not recommended, poor water quality with high algae risk
Water Quality Grade: D, Poor
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 | F |
| Chlorophyll-a (Algae) | 17.1 µg/L | C |
| Trophic State Index (TSI) | 66 | Eutrophic |
High nutrients, frequent algae, reduced clarity
Location
County Ranking
Ranked #4 of 5 lakes in Monroe County
Cleaner Lakes Within 30 Miles
Lk Ontario Lake holds Grade D. One nearby lake has a higher grade.
See full comparison →Nearby Lakes in Monroe County
More Wisconsin Lake Rankings
Other Grade D Lakes in Wisconsin
Eutrophic Lakes in Wisconsin
EPA Impairment Status
Lk Ontario Lake 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)
Data Sources
Water quality data from the EPA Water Quality Portal
Impairment status from EPA ATTAINS 303(d) database
Grading methodology based on Metropolitan Council standards
Most recent sample: 2023-10-24
Monitoring stations: 1