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LakeQuality

Koontz Lake

Starke County, Indiana324 acresView mapDirections

NR
Not rated

Not Rated: one monitoring station are on record, but they measured water clarity only. LakeQuality’s A–F method grades total phosphorus, total nitrogen, chlorophyll-a, and turbidity; clarity is shown, not scored.

Water temp
No reading
No gauge
Clarity
9.8 ft
Secchi · sampled 2020
Level
No reading
No gauge
Trend
Declining
5 years of samples
  • Impaired · Nutrients (phosphorus, nitrogen)
  • Public access
  • Limited data

Koontz Lake in Starke County, Indiana is not rated for water quality — its monitoring record does not meet the evidence bar. Water clarity: 9.8 ft visibility. Surface area: 324.43 acres.

Clarity
9.8 ft
Area
324 acres
Trend
Declining
Public access
Yes
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Watch Koontz Lake’s letter

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Why Koontz Lake has no grade

Koontz Lake has monitoring on record from one station, but only water clarity was measured. LakeQuality’s A–F letter uses total phosphorus, total nitrogen, chlorophyll-a, and turbidity against EPA National Lakes Assessment condition classes. With none of those grading measurements on record, Koontz Lake is Not Rated — not an F. Its 9.8-foot median from 1 readings collected 2020 is still shown as clarity, but clarity alone cannot earn a letter.

Not Rated is EPA Integrated Reporting Category 3 — insufficient information. Everything below that has been measured is still reported on this page.

Sampling is run by IDEM and volunteer programs, and published through the EPA Water Quality Portal. Read the full grading methodology.

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. Grade methodology: LakeQuality methodology.

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 Safety

Not rated

Limited data

The letter is 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.

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Water quality measurements for Koontz Lake

These readings exist but are not enough for an A–F grade — see why.

Moderate clarity, visible to about 9.8 ft. TSI 44.

MetricValueGrade
Water Clarity (Secchi Depth)9.8 ftNot graded
PhosphorusNo recent samples
Chlorophyll-a (Algae)No recent samples
Trophic State Index (TSI)44Mesotrophic

Moderate nutrients, good water quality

Lake Details

CharacteristicValue
Surface Area324 acres
Public AccessYes

No bathymetric survey has been published for Koontz Lake, so its depth is not documented here.

Recreation & Access

1
Boat Landings
Yes
Public 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

Fishing Koontz Lake

Based on 5 years of monitoring data (2020-2025).

MetricTrendChange/YearYears
Water Clarity Declining-0.12 m/yr5
Phosphorus Declining+13.2 µg/L/yr5
Chlorophyll-a Declining+6.5 µg/L/yr5
See year-by-year chart →

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

Nutrients (phosphorus, nitrogen)

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 District
    Koontz Lake · 0.4 mi away · NPDES IN0063606
    Recent violation
  • Dollar General In Walkerton In
    Walkerton · 1 mi away · NPDES INR10L939
  • Materna Mint Distillery Facility
    Walkerton · 3.3 mi away · NPDES IN0063746
  • In Dot Des 1400263 R 37797 Road Rehabilitation
    Walkerton · 3.9 mi away · NPDES INRA15091
  • In Dot Des 1400263 R 37797 Road Rehabilitation
    Walkerton · 3.9 mi away · NPDES INRA04469
  • In Dot Des 1400265 R 37797 Road Rehabilitation
    Walkerton · 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. LakeQuality has not rated this lake (UNRATED) — no nutrient or algae measurement meets the evidence bar (at least 3 samples within 10 years).

What is the water quality grade for Koontz Lake?

Koontz Lake in Starke County, Indiana is not rated for water quality — its monitoring record does not meet the evidence bar. Water clarity: 9.8 ft visibility. Surface area: 324.43 acres.

Is Koontz Lake safe to swim in?

The letter is 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.

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 SocietyNALMS1 sample · 2020
Monitoring station identifiers (1)

Grade thresholds from the EPA National Lakes Assessment (EPA 841-R-24-006, Table 6-3), applied by ecoregion. See how grades are calculated 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