Dutchman Lake
Johnson County, IllinoisView mapDirections
Illinois EPA publishes the water-quality measurements for Dutchman Lake. Here is what has been measured.
- Hypereutrophic
- Impaired · Mercury
- 31 ft max depth
- Public access
- Limited data
Dutchman Lake in Johnson County, Illinois has water-quality measurements published by Illinois EPA, shown here as reported. Water clarity: 2.1 ft visibility. Phosphorus: 59.5 µg/L. Chlorophyll-a (algae): 35.9 µg/L.
Dutchman Lake is a highly nutrient-loaded hypereutrophic lake in Johnson County, Illinois with an estimated average depth of about 31 feet. 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 EPA, last sampled 2021-10-14. Methodology: how these readings are compared.
What Dutchman Lake is good for
From access and monitoring records, not editorial picks.
- Boat launch1 documented ramp
Swimming conditions
Readings onlyLimited data
Based on clarity and algae readings from past sampling — there is no live water temperature and a current cyanobacteria reading for this lake. Check your state or county health department before you swim.
Nutrient and algae readings are not a swimming clearance. Dutchman Lake is listed impaired under Clean Water Act §303(d) (IR 5) for mercury, nutrients (phosphorus, nitrogen). Check local advisories before you swim.
Whether Dutchman Lake is safe to swim in today is a call for the Illinois Environmental Protection Agency and the county health department, who post current advisories. LakeQuality does not issue swimming clearances.
Water quality measurements for Dutchman Lake
These are the measurements Illinois EPA publishes for Dutchman Lake, shown as reported. The condition class beside each reading is the EPA National Lakes Assessment class for this lake’s ecoregion.
Very murky, less than 2.1 ft of visibility. Phosphorus 59.5 µg/L. Chlorophyll-a 35.9 µg/L. TSI 65.
| Measure | Reading | Where it sits |
|---|---|---|
| Water clarity (Secchi depth) | 2.1ft | Measured, not scored How deep a black-and-white disk stays visible from the surface. Higher is clearer. |
| Total phosphorus | 59.5µg/L | Poor GoodFairPoor |
| Chlorophyll-a (algae) | 35.9µg/L | Poor GoodFairPoor |
| Trophic state (TSI)Carlson's 0–100 index of how much algae a lake can support, from clarity, phosphorus and chlorophyll-a. | 65 | Hypereutrophic OligotrophicMesotrophicEutrophicHypereutrophic |
Very high nutrients, dense algae, poor clarity
Ask about Dutchman Lake
Answers come straight from the public measurements and survey records on this page.
Water Temperature
Dutchman Lake typically sits around 71°F at the surface in October. Summer average is about 73°F. Usually warmest in Jul (about 77°F) and coldest in Apr (about 59°F). These are typical values by month — not a live reading.
Column height runs from this lake’s coldest month (59°F) to its warmest (77°F).
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 →
Lake Details
Max depth
~31 ft est.
Public access
Yes
Listed by Illinois EPA
Depth marked “est.” is a modeled maximum from GLOBathy (Khazaei et al. 2022, CC0), not a measured survey. Illinois has not published bathymetry for Dutchman Lake.
Lake Size & Watershed
Watershed (drainage) area
10 sq mi
HydroLAKES / HydroSHEDS
Surface area
86 acres
HydroLAKES / HydroSHEDS
Shoreline
2.6 mi
HydroLAKES / HydroSHEDS
Elevation
433 ft
Size, shoreline, and watershed area from HydroLAKES (HydroSHEDS). Mean depth here is modelled, not surveyed — HydroLAKES v1.0 estimates lake depth from surrounding terrain rather than from soundings. Treat it as an approximation, and prefer a state bathymetric survey where one exists.
Recreation & Access
- Dutchman LakePublic
Named access points in the USGS National Boat Ramps inventory, within about 3 miles. More lakes with boat ramps
Stays via Stay22
Stays near Dutchman Lake
Compare lakeside cabins, hotels, and vacation rentals near Dutchman Lake in Johnson County, Illinois — 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. The water-quality readings cover nutrients and algae, not lodging. Cabins and rentals around Dutchman Lake are listed below.
Top-rated places to stay near Dutchman Lake
Prices for Oct 23–25, 4 adults. Change dates on the map below.
Availability and prices from Stay22 partners (Booking.com, Vrbo, Expedia). We may earn a commission from bookings, at no extra cost to you.
Planning a whole trip? See where to stay at Illinois’s top lakes →
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Fishing Dutchman Lake
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
Designated uses not supporting: Fish consumption, Other.
A Total Maximum Daily Load (TMDL) plan has been approved.
Source: EPA ATTAINS assessment unit IL_RAM · Official waterbody report
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.
Nearby Lakes in Johnson County
Frequently asked questions about Dutchman Lake
Where is Dutchman Lake?
- Dutchman Lake is a lake in Johnson County, Illinois. Its water-quality measurements are published by Illinois EPA and shown on this page as reported.
What is the water quality of Dutchman Lake?
- Dutchman Lake in Johnson County, Illinois has water-quality measurements published by Illinois EPA, shown here as reported. Water clarity: 2.1 ft visibility. Phosphorus: 59.5 µg/L. Chlorophyll-a (algae): 35.9 µg/L.
Is Dutchman Lake safe to swim in?
- Nutrient and algae readings are not a swimming clearance. Dutchman Lake is listed impaired under Clean Water Act §303(d) (IR 5) for mercury, nutrients (phosphorus, nitrogen). Check local advisories before you swim.
What is the water temperature of Dutchman Lake?
- Dutchman Lake typically sits around 71°F at the surface in October, from 161 EPA Water Quality Portal field readings (2016–2021). That is a typical value for the month, not a live reading.
How deep is Dutchman Lake?
- No published bathymetric survey covers Dutchman Lake, so its depth has not been measured. The HydroLAKES global model estimates an average depth of about 31 feet, but that is a modelled estimate derived from surrounding terrain rather than a measurement on the water, so treat it as approximate.
Are there boat ramps on Dutchman Lake?
- Dutchman Lake has 1 documented boat landing in the USGS National Boat Ramps inventory. Named access points include Dutchman Lake. Public access is listed as yes.
Can I fish at Dutchman Lake?
- Dutchman 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 Illinois's fish and wildlife agency, so check its current regulations before you go.
Explore Dutchman Lake across LakeQuality
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Where this data comes from
52 measurements from 3 monitoring stations, 2021. Retrieved from the EPA Water Quality Portal on 2026-08-02.
Collected and reported by
- illinois epa
IL_EPA_WQX52 samples · 2021
Analytical methods
- MEASURED IN FIELD
- Phosphorus by Colorimetry
- 10200 H 2 ~ Chlorophyll a-b-c Determination by spectrophotometer
Monitoring station identifiers (3)
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)
Lake size & watershed from HydroLAKES (HydroSHEDS)
Named boat-access points from the USGS National Boat Ramps inventory