Koontz Lake is a 324-acre productive, nutrient-rich eutrophic lake in Starke County, Indiana. Water quality is graded D based on 1 sampling years through 2020. Overall water quality is declining over recent sampling years. The lake supports 4 documented fish species including Bluegill, Crappie, and Largemouth Bass. Public access is available with 1 public boat landing. Compared to the 2 other monitored lakes in Starke County, Koontz Lake ranks #2 for water quality.
Source: EPA Water Quality Portal sampling records, Indiana DNR, last sampled 2020-07-10. Grade methodology: LakeGrade methodology.
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Swimming Safety
Swimming not recommended, poor water quality with high algae risk
Water Quality Grade: D, Poor
Murky, only visible to about 4.9 ft. Trophic State Index: 54.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 4.9 ft | D |
| Phosphorus | No data | |
| Chlorophyll-a (Algae) | No data | |
| Trophic State Index (TSI) | 54 | Eutrophic |
High nutrients, frequent algae, reduced clarity
Lake Details
| Characteristic | Value |
|---|---|
| Surface Area | 324 acres |
| Public Access | Yes |
Where to stay near Koontz Lake
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Fish Species
Click a species to see every graded lake where it is documented.
Fishing Koontz Lake
Water Quality Trend: ↓ Declining
Based on 5 years of monitoring data (2020-2025).
| Metric | Trend | Change/Year | Years |
|---|---|---|---|
| Water Clarity | ↓ Declining | -0.12 m/yr | 5 |
| Chlorophyll-a | ↓ Declining | +6.5 µg/L/yr | 5 |
Recreation & Access
Location
County Ranking
Ranked #2 of 3 lakes in Starke County
Nearby Lakes in Starke County
Explore Koontz Lake across LakeGrade
More Indiana Lake Rankings
Other Grade D Lakes in Indiana
Eutrophic Lakes in Indiana
More records, surveys & data sources
Reservoir Info (USACE NID)
Koontz Lake is a man-made reservoir impounded by the Koontz Lake Dam (completed 1849), built primarily for recreation on the LAWRENCE PONTIUS DITCH; concrete-type dam, 24 ft tall and 271 ft long.
- Surface area
- 324.43 ac
- Normal storage
- 2,980 ac-ft
- Max storage
- 4,820 ac-ft
- Drainage area
- 6.25 sq mi
- Hazard class
- High
- Owner
- DEPARTMENT OF NATURAL RESOURCES
Source: USACE National Inventory of Dams, NID ID IN00782 · Operator website
EPA Impairment Status
Koontz 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 INK01P1036_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
9 EPA-permitted facilities operate within about 5 miles of Koontz Lake under Clean Water Act (NPDES) discharge permits. 1 facility has a reported Clean Water Act violation in the past three years.
- Koontz Lake Regional Sewer DistrictKoontz Lake · 0.4 mi away · NPDES IN0063606Recent violation
- Dollar General In Walkerton InWalkerton · 1 mi away · NPDES INR10L939
- Materna Mint Distillery FacilityWalkerton · 3.3 mi away · NPDES IN0063746
- In Dot Des 1400263 R 37797 Road RehabilitationWalkerton · 3.9 mi away · NPDES INRA15091
- In Dot Des 1400263 R 37797 Road RehabilitationWalkerton · 3.9 mi away · NPDES INRA04469
- In Dot Des 1400265 R 37797 Road RehabilitationWalkerton · 4 mi away · NPDES INRA04470
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
Public boat-access points from the USGS National Boat Ramps inventory
Most recent sample: 2020-07-10
Monitoring stations: 1