Grays Lake
Lake County, WisconsinEutrophic
Grays Lake is a productive, nutrient-rich eutrophic lake in Lake County, IL. Water quality is graded B based on 2 sampling years through 2021. Compared to the 15 other monitored lakes in Lake County, Grays Lake ranks #5 for water quality.
Source: EPA Water Quality Portal sampling records, local state DNR records, last sampled 2021-10-12. Grade methodology: LakeGrade methodology.
Swimming Safety
Good for swimming, clear water with low algae levels
Water Quality Grade: B, Good
Murky, only visible to about 3.5 ft. Phosphorus level: 18 µg/L. Trophic State Index: 52.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 3.5 ft | D |
| Phosphorus | 18 µg/L | A |
| Chlorophyll-a (Algae) | No data | |
| Trophic State Index (TSI) | 52 | Eutrophic |
High nutrients, frequent algae, reduced clarity
Location
County Ranking
Ranked #5 of 16 lakes in Lake County
Cleaner Lakes Within 30 Miles
Grays Lake holds Grade B. One nearby lake has a higher grade.
See full comparison →Nearby Lakes in Lake County
More Wisconsin Lake Rankings
Other Grade B Lakes in Wisconsin
Eutrophic Lakes in Wisconsin
EPA Impairment Status
Grays Lake is officially listed as impaired under Clean Water Act §303(d) in the 2024 EPA reporting cycle (IR category 5).
Causes of impairment
Source: EPA ATTAINS assessment unit IL_UTL · Official waterbody report · Matched by proximity (2.22 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: 2021-10-12
Monitoring stations: 3