Round Lake
Lake County, Illinois242 acresView mapDirections
Clarity, phosphorus, and algae sit in the clean band for this region.
- Eutrophic
- Impaired · Nutrients (phosphorus, nitrogen)
- #5 of 19 in the county
- 32 ft max depth
- Public access
- Limited data
Round Lake in Lake County, Illinois has a water quality grade of B (Good). Water clarity: 7.4 ft visibility. Phosphorus: 20.5 µg/L. Chlorophyll-a (algae): 7.1 µg/L. Surface area: 242 acres.
- Clarity
- 7.4 ft
- Typical in August
- 72°F
- Max depth
- ~32 ft est.
- Area
- 242 acres
- Type
- Eutrophic
- Public access
- Yes
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Round Lake is a 242-acre productive, nutrient-rich eutrophic lake in Lake County, Illinois with an estimated average depth of about 32 feet. Water quality is graded B based on 2 sampling years through 2022. Limited fish-species data available. Public access is available with 1 public boat landing. Compared to the 18 other monitored lakes in Lake County, Round Lake ranks #5 for water quality.
Source: EPA Water Quality Portal sampling records, Illinois EPA, last sampled 2022-10-12. Grade methodology: LakeQuality methodology.
What Round 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 B is nutrients and algae, not a swimming clearance. Round Lake is listed impaired under Clean Water Act §303(d) (IR 5) for nutrients (phosphorus, nitrogen). Check local advisories before you swim.
Water Quality Grade: B (Good)
Moderate clarity, visible to about 7.4 ft. Phosphorus 20.5 µg/L. Chlorophyll-a 7.1 µg/L. TSI 49. The letter is not a swimming clearance.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 7.4 ft | Not graded |
| Phosphorus | 20.5 µg/L | Good |
| Chlorophyll-a (Algae) | 7.1 µg/L | Good |
| Trophic State Index (TSI) | 49 | Eutrophic |
High nutrients, frequent algae, reduced clarity
Water Temperature
Round Lake typically sits around 72°F at the surface in August. Summer average is about 72°F. Usually warmest in Jul (about 75°F) and coldest in May (about 59°F). These are typical values by month — not a live reading.
Typical surface water temperature by month, from 380 field readings (2012–2022) via the EPA Water Quality Portal. See the full Round Lake water temperature breakdown →
Lake Details
| Characteristic | Value |
|---|---|
| Maximum Depth | ~32 ft est. |
| Average Depth | ~12 ft est. |
| Surface Area | 242 acres |
| Public Access | Yes |
Depth marked “est.” is a modeled maximum from GLOBathy (Khazaei et al. 2022, CC0), not a measured survey. Illinois has not published bathymetry for Round Lake.
Lake Size & Watershed
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
- Lakefront ParkPublic
Named access points in the USGS National Boat Ramps inventory, within about 3 miles. More lakes with boat ramps
Fishing Round Lake
Reservoir Info (USACE NID)
Round Lake is a man-made reservoir impounded by the Round Lake Dam (completed 1945), built primarily for recreation on the TRIB SQUAW CREEK; earth-type dam, 9 ft tall and 140 ft long.
- Surface area
- 242 ac
- Normal storage
- 976 ac-ft
- Max storage
- 1,484 ac-ft
- Drainage area
- 2.5 sq mi
- Hazard class
- Significant
- Owner
- VILLAGE OF ROUND LAKE BEACH
Source: USACE National Inventory of Dams, NID ID IL00593 · Operator website
EPA Impairment Status
Round 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_RTZP · Official waterbody report · Matched by proximity (1.29 km)
Regulated Pollution Sources Nearby
1 EPA-permitted facility operate within about 5 miles of Round Lake under Clean Water Act (NPDES) discharge permits. 1 facility has a reported Clean Water Act violation in the past three years.
- Fonks Home Center, Inc. - Hickory HavenKansasville · 3.4 mi away · NPDES WI0030660Recent 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 #5 of 19 lakes in Lake County
Nearby Lakes in Lake County
Frequently asked questions about Round Lake
Where is Round Lake?
- Round Lake is a lake in Lake County, Illinois. LakeQuality grades it B for nutrients and algae. The letter is not a swimming clearance.
What is the water quality grade for Round Lake?
- Round Lake in Lake County, Illinois has a water quality grade of B (Good). Water clarity: 7.4 ft visibility. Phosphorus: 20.5 µg/L. Chlorophyll-a (algae): 7.1 µg/L. Surface area: 242 acres.
Is Round Lake safe to swim in?
- The B is nutrients and algae, not a swimming clearance. Round Lake is listed impaired under Clean Water Act §303(d) (IR 5) for nutrients (phosphorus, nitrogen). Check local advisories before you swim.
What is the water temperature of Round Lake?
- Round Lake typically sits around 72°F at the surface in August, from 380 EPA Water Quality Portal field readings (2012–2022). That is a typical value for the month, not a live reading.
How deep is Round Lake?
- No published bathymetric survey covers Round Lake, so its depth has not been measured. The HydroLAKES global model estimates an average depth of about 32 feet, but that is a modelled estimate derived from surrounding terrain rather than a measurement on the water, so treat it as approximate. The lake covers 242 acres.
Are there boat ramps on Round Lake?
- Round Lake has 1 documented boat landing in the USGS National Boat Ramps inventory. Named access points include Lakefront Park. Public access is listed as yes.
Explore Round Lake across LakeQuality
Depth, room, public access, and the state wake-sport rules
Species activity outlook by water temperature and season
Top lakes and where to stay in the Chain O'Lakes area
Where to stay at Illinois's top lakes, each with its grade
High nutrients, frequent algae, reduced clarity
Illinois's cleanest and most-polluted lakes, ranked
More Illinois Lake Rankings
Other Grade B Lakes in Illinois
Eutrophic Lakes in Illinois
Where this data comes from
42 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_WQX42 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)
Lake size & watershed from HydroLAKES (HydroSHEDS)
Named boat-access points from the USGS National Boat Ramps inventory