Monee Lake
Will County, IllinoisView mapDirections
Nutrients and algae run above the regional average.
- Eutrophic
- Impaired · Mercury
- #1 of 1 in the county
- Public access
- Limited data
Monee Lake in Will County, Illinois has a water quality grade of D (Nutrient-rich). Water clarity: 4.9 ft visibility. Phosphorus: 139 µg/L. Chlorophyll-a (algae): 16.7 µg/L.
- Clarity
- 4.9 ft
- Typical in August
- 77°F
- Type
- Eutrophic
- Phosphorus
- 139 µg/L
- Chlorophyll-a
- 16.7 µg/L
- Public access
- Yes
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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 grade measures nutrients and algae, not lodging — cabins and rentals around Monee Lake are listed below.
Top-rated places to stay near Monee Lake
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Monee Lake is a productive, nutrient-rich eutrophic lake in Will County, Illinois. Water quality is graded D based on 2 sampling years through 2022. 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. Grade methodology: LakeQuality methodology.
What Monee Lake is good for
From access and monitoring records, not editorial picks.
- Boat launch1 documented ramp
Swimming Safety
Grade onlyLimited data
Based on clarity and algae grades from past sampling — we do not hold live water temperature and a current cyanobacteria reading for this lake. Check your state or county health department before you swim.
The D is nutrients and algae, 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.
Water Quality Grade: D (Nutrient-rich)
Murky, only visible to about 4.9 ft. Phosphorus 139 µg/L. Chlorophyll-a 16.7 µg/L. TSI 63. The letter is not a swimming clearance.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 4.9 ft | Not graded |
| Phosphorus | 139 µg/L | Poor |
| Chlorophyll-a (Algae) | 16.7 µg/L | Fair |
| Trophic State Index (TSI) | 63 | Eutrophic |
High nutrients, frequent algae, reduced clarity
Water Temperature
Monee Lake typically sits around 77°F at the surface in August. 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.
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
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
Source: EPA ATTAINS assessment unit IL_RFH · Official waterbody report · Matched by proximity (0.05 km)
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.
County Ranking
Ranked #1 of 1 lakes in Will County
Nearby Lakes in Will County
Frequently asked questions about Monee Lake
Where is Monee Lake?
- Monee Lake is a lake in Will County, Illinois. LakeQuality grades it D for nutrients and algae. The letter is not a swimming clearance.
What is the water quality grade for Monee Lake?
- Monee Lake in Will County, Illinois has a water quality grade of D (Nutrient-rich). Water clarity: 4.9 ft visibility. Phosphorus: 139 µg/L. Chlorophyll-a (algae): 16.7 µg/L.
Is Monee Lake safe to swim in?
- The D is nutrients and algae, 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 77°F at the surface in August, 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.
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 Illinois Lake Rankings
Other Grade D 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)
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