Monee Lake
Will County, IllinoisView mapDirections
Illinois EPA publishes the water-quality measurements for Monee Lake. Here is what has been measured.
- Eutrophic
- Impaired · Mercury
- Public access
- Limited data
Monee Lake in Will County, Illinois has water-quality measurements published by Illinois EPA, shown here as reported. Water clarity: 4.9 ft visibility. Phosphorus: 139 µg/L. Chlorophyll-a (algae): 16.7 µg/L.
Monee Lake is a productive, nutrient-rich eutrophic lake in Will County, Illinois. Limited fish-species data available. Public access is available with 1 public boat landing.
Source: EPA Water Quality Portal sampling records, Illinois EPA, last sampled 2022-10-27. Methodology: how these readings are compared.
What Monee 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. Monee Lake is listed impaired under Clean Water Act §303(d) (IR 5) for mercury, nutrients (phosphorus, nitrogen), pesticides. Check local advisories before you swim.
Whether Monee 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 Monee Lake
These are the measurements Illinois EPA publishes for Monee Lake, shown as reported. The condition class beside each reading is the EPA National Lakes Assessment class for this lake’s ecoregion.
Murky, only visible to about 4.9 ft. Phosphorus 139 µg/L. Chlorophyll-a 16.7 µg/L. TSI 63.
| Measure | Reading | Where it sits |
|---|---|---|
| Water clarity (Secchi depth) | 4.9ft | Measured, not scored How deep a black-and-white disk stays visible from the surface. Higher is clearer. |
| Total phosphorus | 139µg/L | Poor GoodFairPoor |
| Chlorophyll-a (algae) | 16.7µg/L | Fair GoodFairPoor |
| Trophic state (TSI)Carlson's 0–100 index of how much algae a lake can support, from clarity, phosphorus and chlorophyll-a. | 63 | Eutrophic OligotrophicMesotrophicEutrophicHypereutrophic |
High nutrients, frequent algae, reduced clarity
Ask about Monee Lake
Answers come straight from the public measurements and survey records on this page.
Water Temperature
Monee Lake typically sits around 59°F at the surface in October. Summer average is about 75°F. Usually warmest in Jul (about 77°F) and coldest in Oct (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 349 field readings (2010–2022) via the EPA Water Quality Portal. See the full Monee Lake water temperature breakdown →
Recreation & Access
- Monee ReservoirPublic
Named access points in the USGS National Boat Ramps inventory, within about 3 miles. More lakes with boat ramps
Stays via Stay22
Stays near Monee Lake
Compare lakeside cabins, hotels, and vacation rentals near Monee Lake in Will 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 Monee Lake are listed below.
Top-rated places to stay near Monee Lake
Prices for Oct 30–Nov 1, 4 adults. Change dates on the map below.
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Planning a whole trip? See where to stay at Illinois’s top lakes →
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Fishing Monee Lake
Reservoir Info (USACE NID)
Monee Lake is a man-made reservoir impounded by the Monee Reservoir Dam (completed 1900), built primarily for recreation on the TRIB ROCK CREEK; earth-type dam, 29 ft tall and 2,400 ft long.
- Normal storage
- 320 ac-ft
- Max storage
- 650 ac-ft
- Hazard class
- Significant
- Owner
- FOREST PRESERVE DISTRICT OF WILL COUNTY
Source: USACE National Inventory of Dams, NID ID IL00566 · Operator website
EPA Impairment Status
Monee 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.
Source: EPA ATTAINS assessment unit IL_RFH · Official waterbody report
Regulated Pollution Sources Nearby
1 EPA-permitted facility operate within about 5 miles of Monee Lake under Clean Water Act (NPDES) discharge permits. 1 facility has a reported Clean Water Act violation in the past three years.
- Idot - I-57 Rest AreaPeotone · 0.4 mi away · NPDES IL0032051Recent violation
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 Will County
Frequently asked questions about Monee Lake
Where is Monee Lake?
- Monee Lake is a lake in Will County, Illinois. Its water-quality measurements are published by Illinois EPA and shown on this page as reported.
What is the water quality of Monee Lake?
- Monee Lake in Will County, Illinois has water-quality measurements published by Illinois EPA, shown here as reported. Water clarity: 4.9 ft visibility. Phosphorus: 139 µg/L. Chlorophyll-a (algae): 16.7 µg/L.
Is Monee Lake safe to swim in?
- Nutrient and algae readings are not a swimming clearance. Monee Lake is listed impaired under Clean Water Act §303(d) (IR 5) for mercury, nutrients (phosphorus, nitrogen), pesticides. Check local advisories before you swim.
What is the water temperature of Monee Lake?
- Monee Lake typically sits around 59°F at the surface in October, from 349 EPA Water Quality Portal field readings (2010–2022). That is a typical value for the month, not a live reading.
Are there boat ramps on Monee Lake?
- Monee Lake has 1 documented boat landing in the USGS National Boat Ramps inventory. Named access points include Monee Reservoir. Public access is listed as yes.
Can I fish at Monee Lake?
- Monee 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 Monee Lake across LakeQuality
Planning a trip around Indiana Dunes?
Monee Lake is about 38 miles from Indiana Dunes National Park. Crowds there swing hard by season, so the month you pick changes both how busy the park is and what lodging costs.
Best time to visit Indiana Dunes →More lakes in Illinois
Other Lakes in Illinois
Eutrophic Lakes in Illinois
Where this data comes from
31 measurements from 3 monitoring stations, 2022. Retrieved from the EPA Water Quality Portal on 2026-08-02.
Collected and reported by
- illinois epa
IL_EPA_WQX31 samples · 2022
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)
Named boat-access points from the USGS National Boat Ramps inventory