Long Lake
Lake County, WisconsinEutrophic
Long Lake is a productive, nutrient-rich eutrophic lake in Lake County, IL. Water quality is graded D based on 2 sampling years through 2022. Compared to the 15 other monitored lakes in Lake County, Long Lake ranks #11 for water quality.
Source: EPA Water Quality Portal sampling records, local state DNR records, last sampled 2022-10-12. Grade methodology: LakeGrade methodology.
Swimming Safety
Swimming not recommended, poor water quality with high algae risk
Water Quality Grade: D, Poor
Very murky, less than 2.9 ft of visibility. Phosphorus level: 41.5 µg/L. Trophic State Index: 60.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 2.9 ft | F |
| Phosphorus | 41.5 µg/L | C |
| Chlorophyll-a (Algae) | No data | |
| Trophic State Index (TSI) | 60 | Eutrophic |
High nutrients, frequent algae, reduced clarity
Location
County Ranking
Ranked #11 of 16 lakes in Lake County
Cleaner Lakes Within 30 Miles
Long Lake holds Grade D. 2 nearby lakes hold higher grades.
- BRound LakeLake County · 2.6 mi · Two grade letters higher (D → B)
- BGrays LakeLake County · 4.6 mi · Two grade letters higher (D → B)
Nearby Lakes in Lake County
More Wisconsin Lake Rankings
Other Grade D Lakes in Wisconsin
Eutrophic Lakes in Wisconsin
EPA Impairment Status
Long Lake is officially listed as impaired under Clean Water Act §303(d) in the 2024 EPA reporting cycle (IR category 4A).
Causes of impairment
A Total Maximum Daily Load (TMDL) plan has been approved.
Source: EPA ATTAINS assessment unit IL_RTJ · Official waterbody report
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: 2022-10-12
Monitoring stations: 3