Lily Lake
McHenry County, WisconsinEutrophic
Lily Lake is a productive, nutrient-rich eutrophic lake in McHenry County, IL. Water quality is graded B based on 2 sampling years through 2021. Compared to the 4 other monitored lakes in McHenry County, Lily Lake ranks #3 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
Very murky, less than 3.3 ft of visibility. Phosphorus level: 16 µg/L. Trophic State Index: 52.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 3.3 ft | D |
| Phosphorus | 16 µg/L | A |
| Chlorophyll-a (Algae) | No data | |
| Trophic State Index (TSI) | 52 | Eutrophic |
High nutrients, frequent algae, reduced clarity
Location
County Ranking
Ranked #3 of 5 lakes in McHenry County
Cleaner Lakes Within 30 Miles
Lily Lake holds Grade B. 2 nearby lakes hold higher grades.
- BSilver LakeMcHenry County · 6.2 mi · Higher overall water quality score
- BRound LakeLake County · 7 mi · Higher overall water quality score
Nearby Lakes in McHenry County
More Wisconsin Lake Rankings
Other Grade B Lakes in Wisconsin
Eutrophic Lakes in Wisconsin
EPA Impairment Status
Lily 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_RTZJ · 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: 2021-10-12
Monitoring stations: 3