Dutchman Lake is a productive, nutrient-rich eutrophic lake in Johnson County, Illinois. Water quality is graded D based on 2 sampling years through 2021. Limited fish-species data available. Public access is available with 1 public boat landing. Compared to the 1 other monitored lakes in Johnson County, Dutchman Lake ranks #2 for water quality.
Source: EPA Water Quality Portal sampling records, Illinois DNR, last sampled 2021-10-14. 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
Very murky, less than 2.1 ft of visibility. Phosphorus level: 37.5 µg/L. Trophic State Index: 61.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 2.1 ft | F |
| Phosphorus | 37.5 µg/L | C |
| Chlorophyll-a (Algae) | No data | |
| Trophic State Index (TSI) | 61 | Eutrophic |
High nutrients, frequent algae, reduced clarity
Where to stay near Dutchman Lake
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Fishing Dutchman Lake
Invasive & Introduced Species
Red chips are ecologically harmful invasive species. Gray chips are stocked or introduced fish that aren't a current ecological concern.
Source: USGS Nonindigenous Aquatic Species (NAS) Database. Hover a chip to see scientific name, ecological context, status, and first-observed year.
Recreation & Access
Water Temperature
Dutchman Lake averages about 73°F at the surface in summer, usually warmest in Jul (about 77°F) and coldest in Apr (about 59°F). These are typical values by month — not a live reading.
Typical surface water temperature by month, from 161 field readings (2016–2021) via the EPA Water Quality Portal. See the full Dutchman Lake water temperature breakdown →
Location
County Ranking
Ranked #2 of 2 lakes in Johnson County
Cleaner Lakes Within 30 Miles
Dutchman Lake holds Grade D. 4 nearby lakes hold higher grades.
- BGlendale LakePope County · 15.4 mi · Two grade letters higher (D → B)
- BOne Horse Gap LakePope County · 26.1 mi · Two grade letters higher (D → B)
- CVienna Correctional Center LakeJohnson County · 10.1 mi · Higher grade (D → C)
- CLake of EgyptWilliamson County · 7.6 mi · Higher grade (D → C)
Nearby Lakes in Johnson County
Explore Dutchman Lake across LakeGrade
More Illinois Lake Rankings
Other Grade D Lakes in Illinois
Eutrophic Lakes in Illinois
More records, surveys & data sources
EPA Impairment Status
Dutchman Lake is officially listed as impaired under Clean Water Act §303(d) in the 2024 EPA reporting cycle (IR category 5).
Causes of impairment
A Total Maximum Daily Load (TMDL) plan has been approved.
Source: EPA ATTAINS assessment unit IL_RAM · Official waterbody report
Lake Size & Watershed
Size, shoreline, and watershed area from HydroLAKES (HydroSHEDS). Mean depth is a modeled estimate.
Regulated Pollution Sources Nearby
2 EPA-permitted facilities operate within about 5 miles of Dutchman Lake under Clean Water Act (NPDES) discharge permits. 1 facility has a reported Clean Water Act violation in the past three years.
- Buncombe Stp, Village OfBuncombe · 3.5 mi away · NPDES IL0067148Recent violation
- Illinois Department Of Natural ResourcesGoreville · 4.5 mi away · NPDES IL0051845
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: 2021-10-14
Monitoring stations: 3