Lilly Lake
Kenosha County, WisconsinMesotrophic
Lilly Lake earns an A — every scored parameter (clarity and phosphorus) rates among the best monitored waters in Kenosha County. With clarity and phosphorus scored, the sub-grades cluster within a letter of each other, pointing to stable conditions rather than one specific stressor.
Mesotrophic conditions dominate at Lilly Lake: enough nutrients for a healthy fishery, not so much that algal blooms become a chronic problem. A maximum depth of 22 ft puts Lilly Lake in the middle of Wisconsin's depth distribution. At 85 acres, Lilly Lake sits below the Wisconsin median: a small water where shoreline activity has an outsized effect on water quality. Among the 13 graded lakes in Kenosha County, Lilly Lake ranks 3 — in the top quartile locally.
Lilly Lake carries an invasive watermilfoil record — boat-launch decontamination and shoreline care matter more here than at uninfested lakes. The fishery is bass-led, with 3 documented species across the lake's records. The grade is based on limited monitoring — fewer than three independent measurement years contribute, so future updates may shift the letter.
Source: EPA Water Quality Portal sampling records, Wisconsin DNR Surface Water, last sampled 2025-09-20. Grade methodology: LakeGrade methodology.
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Swimming Safety
Excellent for swimming, crystal clear water with minimal algae
Water Quality Grade: A, Excellent
Good clarity, visible to about 13.5 ft. Phosphorus level: 13.6 µg/L. Trophic State Index: 41.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 13.5 ft | B |
| Phosphorus | 13.6 µg/L | A |
| Chlorophyll-a (Algae) | No data | |
| Trophic State Index (TSI) | 41 | Mesotrophic |
Moderate nutrients, good water quality
Lake Details
| Characteristic | Value |
|---|---|
| Maximum Depth | 22 ft |
| Surface Area | 85 acres |
Fish Species
Click a species to see all Wisconsin and Minnesota lakes where it is found.
→ Best fishing times for Lilly Lake (14-day solunar calendar)
→ Is it safe to eat fish from Lilly Lake? (mercury & PFAS guide)
→ Lilly Lake fishing regulations (limits, seasons, special rules)
Invasive & Introduced Species
Red chips are ecologically harmful invasive species. Gray chips are stocked or introduced fish that aren't a current ecological concern.
Water Quality Trend: ↑ Improving
Based on 6 years of monitoring data (2020-2025).
| Metric | Trend | Change/Year | Years |
|---|---|---|---|
| Water Clarity | ↑ Improving | +0.339 m/yr | 6 |
| Phosphorus | ↑ Improving | -0.54 µg/L/yr | 6 |
Location
County Ranking
Ranked #3 of 13 lakes in Kenosha County
Nearby Lakes in Kenosha County
More Wisconsin Lake Rankings
State Parks Near Lilly Lake
Other Grade A Lakes in Wisconsin
Washington County · Clarity: 11.8 ft
Washington County · Clarity: 12.6 ft
Walworth County · Clarity: 11 ft
Waukesha County · Clarity: 11.3 ft
Walworth County · Clarity: 20.2 ft
Oconto County · Clarity: 11 ft
Mesotrophic Lakes in Wisconsin
WI DNR Lake Profile
Authoritative data from the Wisconsin DNR LakePages. Monitored by volunteers since 2002. 3 stations on file (most recent sample 2026).
Fish Species (DNR-rated)
Data Sources
Water quality data from the EPA Water Quality Portal
Grading methodology based on Metropolitan Council standards
Most recent sample: 2025-09-20
Monitoring stations: 1