Koontz Lake
Starke County, Indiana324 acresView mapDirections
IDEM publishes the water-quality measurements for Koontz Lake. Here is what has been measured.
- Impaired · Nutrients (phosphorus, nitrogen)
- Public access
- Limited data
Koontz Lake in Starke County, Indiana has water-quality measurements published by IDEM, shown here as reported. Water clarity: 9.8 ft visibility. Surface area: 324.43 acres.
Koontz Lake is a 324-acre lake in Starke County, Indiana. Overall water quality is declining over recent sampling years. Limited fish-species data available. Public access is available with 1 public boat landing.
Source: EPA Water Quality Portal sampling records, IDEM, last sampled 2020-07-10. Methodology: how these readings are compared.
Koontz Lake covers about 320 acres in Starke County. It has one public boat landing. For a place on the water, look through cabin and lake-house rentals near Koontz Lake on Vrbo. For a hotel or motel room, Booking.com and Expedia both search around the lake.
What Koontz Lake is good for
From access and monitoring records, not editorial picks.
- Clear water9.8 ft of visibility
- Boat launch1 documented ramp
Swimming conditions
No readingRecreation use not supported
Nutrient and algae readings are not a swimming clearance. Koontz Lake is listed impaired under Clean Water Act §303(d) (IR 5) for nutrients (phosphorus, nitrogen). Check local advisories before you swim.
Whether Koontz Lake is safe to swim in today is a call for the Indiana Department of Environmental Management and the county health department, who post current advisories. LakeQuality does not issue swimming clearances.
Water quality measurements for Koontz Lake
These are the measurements IDEM publishes for Koontz Lake, shown as reported. The condition class beside each reading is the EPA National Lakes Assessment class for this lake’s ecoregion.
Moderate clarity, visible to about 9.8 ft. TSI 44.
| Measure | Reading | Where it sits |
|---|---|---|
| Water clarity (Secchi depth) | 9.8ft | Measured, not scored How deep a black-and-white disk stays visible from the surface. Higher is clearer. |
| Total phosphorus | No reading The nutrient that most limits algae growth in freshwater. More phosphorus, more algae potential. | |
| Chlorophyll-a (algae) | No reading The green pigment in algae — a direct measure of how much algae is in the water. | |
| Trophic state (TSI)Carlson's 0–100 index of how much algae a lake can support, from clarity, phosphorus and chlorophyll-a. | 44 | Mesotrophic OligotrophicMesotrophicEutrophicHypereutrophic |
Moderate nutrients, good water quality
Ask about Koontz Lake
Answers come straight from the public measurements and survey records on this page.
Lake Details
Surface area
324 acres
Public access
Yes
Listed by IDEM
No bathymetric survey has been published for Koontz Lake, so its depth is not documented here.
Recreation & Access
- Tri-County Fish & Wildlife AreaPublic
Named access points in the USGS National Boat Ramps inventory, within about 3 miles. More lakes with boat ramps
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Stays near Koontz Lake
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Fishing Koontz Lake
Water Quality Trend: Worsening
Based on 5 years of monitoring (2020–2024).
Water clarity
Worsening5 years
Phosphorus
Worsening+13.2 µg/L/yr5 years
Chlorophyll-a
Worsening+6.5 µg/L/yr5 years
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
Designated uses not supporting: Recreation.
Source: EPA ATTAINS assessment unit INK01P1036_00 · Official waterbody report
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.
Nearby Lakes in Starke County
Frequently asked questions about Koontz Lake
Where is Koontz Lake?
- Koontz Lake is a lake in Starke County, Indiana. Its water-quality measurements are published by IDEM and shown on this page as reported.
What is the water quality of Koontz Lake?
- Koontz Lake in Starke County, Indiana has water-quality measurements published by IDEM, shown here as reported. Water clarity: 9.8 ft visibility. Surface area: 324.43 acres.
Is Koontz Lake safe to swim in?
- Nutrient and algae readings are not a swimming clearance. Koontz Lake is listed impaired under Clean Water Act §303(d) (IR 5) for nutrients (phosphorus, nitrogen). Check local advisories before you swim.
Are there boat ramps on Koontz Lake?
- Koontz Lake has 1 documented boat landing in the USGS National Boat Ramps inventory. Named access points include Tri-County Fish & Wildlife Area. Public access is listed as yes.
Can I fish at Koontz Lake?
- Koontz Lake has 1 documented boat landing in the USGS National Boat Ramps inventory. Seasons, size and bag limits, and whether you need a license are set by Indiana's fish and wildlife agency, so check its current regulations before you go.
Explore Koontz Lake across LakeQuality
Depth, room, public access, and the state wake-sport rules
Species activity outlook by water temperature and season
Where to stay at Indiana's top lakes, each with its readings
Indiana's cleanest lakes, ranked on agency measurements
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Where this data comes from
1 measurement from 1 monitoring station, 2020. Retrieved from the EPA Water Quality Portal on 2026-08-02.
Collected and reported by
- North American Lake Management Society
NALMS1 sample · 2020
Monitoring station identifiers (1)
EPA condition classes from the National Lakes Assessment (EPA 841-R-24-006, Table 6-3), applied by ecoregion. See where the data comes from and data sources.
Other records on this page
Impairment status from EPA ATTAINS 303(d) database
Regulated discharger data from EPA ECHO (ICIS-NPDES)
Named boat-access points from the USGS National Boat Ramps inventory