Loch Lomond Lake is a 72-acre cold, clear oligotrophic lake in Lake County, Illinois. Water quality is graded A based on 1 sampling years through 2020. Limited fish-species data available. Public access is available with 1 public boat landing. Compared to the 15 other monitored lakes in Lake County, Loch Lomond Lake ranks #1 for water quality.
Source: EPA Water Quality Portal sampling records, Illinois DNR, last sampled 2020-09-19. Grade methodology: LakeGrade methodology.
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Swimming Safety
Excellent for swimming, crystal clear water with minimal algae
Water Quality Grade: A, Excellent
Crystal clear, you can see 16.5 ft down. Trophic State Index: 37.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 16.5 ft | A |
| Phosphorus | No data | |
| Chlorophyll-a (Algae) | No data | |
| Trophic State Index (TSI) | 37 | Oligotrophic |
Low nutrients, clear water, excellent for swimming
Lake Details
| Characteristic | Value |
|---|---|
| Surface Area | 72 acres |
| Public Access | Yes |
Where to stay near Loch Lomond Lake
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Fishing Loch Lomond Lake
Recreation & Access
Location
County Ranking
Ranked #1 of 16 lakes in Lake County
Nearby Lakes in Lake County
Explore Loch Lomond Lake across LakeGrade
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
Low nutrients, clear water, excellent for swimming
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More records, surveys & data sources
Reservoir Info (USACE NID)
Loch Lomond Lake is a man-made reservoir impounded by the Loch Lomond Dam (completed 1958), built primarily for recreation on the BULL CREEK; earth-type dam, 14 ft tall and 550 ft long.
- Surface area
- 72 ac
- Normal storage
- 140 ac-ft
- Max storage
- 821 ac-ft
- Drainage area
- 1.8 sq mi
- Hazard class
- Significant
- Owner
- LOCH LOMOND PROPERTY OWNERS ASSOCIATION
Source: USACE National Inventory of Dams, NID ID IL00652 · Operator website
EPA Impairment Status
Loch Lomond 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_RGU · Official waterbody report
Lake Size & Watershed
Size, shoreline, and watershed area from HydroLAKES (HydroSHEDS). Mean depth is a modeled estimate.
Regulated Pollution Sources Nearby
10 EPA-permitted facilities operate within about 5 miles of Loch Lomond Lake under Clean Water Act (NPDES) discharge permits, including 3 classified by the EPA as major dischargers. 7 facilities have a reported Clean Water Act violation in the past three years.
- Libertyville Stp, Village OfLibertyville · 3.9 mi away · NPDES IL0029530MajorRecent violation
- Mundelein Stp, Village OfLibertyville · 4 mi away · NPDES IL0022501MajorRecent violation
- Lcpwd-New Century Town WrfVernon Hills · 4.9 mi away · NPDES IL0022071MajorRecent violation
- University Of St Mary Of The Lake / Mundelein Seminary StpMundelein · 1 mi away · NPDES IL0024350Recent violation
- Dayspring Bible College And Seminary StpMundelein · 1.2 mi away · NPDES IL0050661Recent violation
- Fremont School District 79 - StpMundelein · 2.8 mi away · NPDES IL0034746Recent 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.
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: 2020-09-19
Monitoring stations: 1