Winona Lake is a productive, nutrient-rich eutrophic lake in Kosciusko County, Indiana. Water quality is graded F based on 1 sampling years through 2021. Water clarity is improving over recent sampling years. The lake supports 6 documented fish species including Bluegill, Catfish, and Crappie. Public access is available. Compared to the 18 other monitored lakes in Kosciusko County, Winona Lake ranks #14 for water quality.
Source: EPA Water Quality Portal sampling records, Indiana DNR, last sampled 2021-08-09. Grade methodology: LakeGrade methodology.
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Swimming Safety
Based on E. coli testing, Winona Lake routinely exceeded the EPA safe-swimming threshold (235 MPN/100mL) — on 29.2% of 24 samples across 3 seasons.
This is a historical summary of past testing, not a current condition — bacteria levels change quickly, especially after rain. Always check Indiana’s current beach and health-department advisories before swimming.
Water Quality Grade: F, Very Poor
Very murky, less than 2.8 ft of visibility. Trophic State Index: 62.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 2.8 ft | F |
| Phosphorus | No data | |
| Chlorophyll-a (Algae) | No data | |
| Trophic State Index (TSI) | 62 | Eutrophic |
High nutrients, frequent algae, reduced clarity
Where to stay near Winona Lake
Compare lakeside cabins, hotels, and vacation rentals near Winona Lake in Kosciusko County, Indiana — live availability and prices for your trip. Switch the map to Satellite to see the lake and how close each stay is to the water.
Top-rated places to stay near Winona Lake
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Fish Species
Click a species to see every graded lake where it is documented.
Fishing Winona Lake
Water Quality Trend: → Stable
Based on 3 years of monitoring data (2020-2025).
| Metric | Trend | Change/Year | Years |
|---|---|---|---|
| Water Clarity | ↑ Improving | +0.125 m/yr | 3 |
| Chlorophyll-a | ↓ Declining | +3.55 µg/L/yr | 2 |
Location
County Ranking
Ranked #14 of 19 lakes in Kosciusko County
Nearby Lakes in Kosciusko County
Explore Winona Lake across LakeGrade
Fish species and top-graded lakes across Indiana
Fish species and best lakes in Kosciusko County
Species activity outlook by water temperature and season
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High nutrients, frequent algae, reduced clarity
Indiana's cleanest and most-polluted lakes, ranked
More Indiana Lake Rankings
Other Grade F Lakes in Indiana
Eutrophic Lakes in Indiana
More records, surveys & data sources
EPA Impairment Status
Winona 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 INB06P1007_00 · Official waterbody report
Lake Size & Watershed
Size, shoreline, and watershed area from HydroLAKES (HydroSHEDS). Mean depth is a modeled estimate.
Regulated Pollution Sources Nearby
19 EPA-permitted facilities operate within about 5 miles of Winona Lake under Clean Water Act (NPDES) discharge permits.
- Winona Lake Municipal WwtpWinona Lake · 0.5 mi away · NPDES IN0024881
- Crystal Lake Egg Products IncWarsaw · 0.7 mi away · NPDES IN0046191
- Associated Milk Producers IncWarsaw · 0.9 mi away · NPDES IN0001554
- Grace College Residence HallWinona Lake · 0.9 mi away · NPDES INR10K711
- Grace College Athletic Track And FieldWinona Lake · 1.2 mi away · NPDES INR10L867
- Lake City Greenway - Park Avenue To Grace CollegeWinona Lake · 1.2 mi away · NPDES INR10H036
Facilities permitted to discharge under the Clean Water Act within ~5 miles; proximity does not by itself mean a facility affects this lake. Source: EPA ECHO (ICIS-NPDES), as of 2026-07.
Data Sources
Water quality data from the EPA Water Quality Portal
Impairment status from EPA ATTAINS 303(d) database
Regulated discharger data from EPA ECHO (ICIS-NPDES)
Lake size & watershed from HydroLAKES (HydroSHEDS)
Grading methodology based on Metropolitan Council standards
Most recent sample: 2021-08-09
Monitoring stations: 1