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LakeQuality

Loch Lomond Lake

Lake County, Illinois72 acresView mapDirections

NR
Not rated

Not Rated: one monitoring station are on record, but they measured water clarity only. LakeQuality’s A–F method grades total phosphorus, total nitrogen, chlorophyll-a, and turbidity; clarity is shown, not scored.

Water temp
No reading
No gauge
Clarity
16.5 ft
Secchi · sampled 2020
Level
No reading
No gauge
Trend
No reading
Not enough history
  • Impaired · Nutrients (phosphorus, nitrogen)
  • 38 ft max depth
  • Public access
  • Limited data

Loch Lomond Lake in Lake County, Illinois is not rated for water quality — its monitoring record does not meet the evidence bar. Water clarity: 16.5 ft visibility. Surface area: 72 acres.

Clarity
16.5 ft
Max depth
~38 ft est.
Area
72 acres
Public access
Yes
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Watch Loch Lomond Lake’s letter

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Why Loch Lomond Lake has no grade

Loch Lomond Lake has monitoring on record from one station, but only water clarity was measured. LakeQuality’s A–F letter uses total phosphorus, total nitrogen, chlorophyll-a, and turbidity against EPA National Lakes Assessment condition classes. With none of those grading measurements on record, Loch Lomond Lake is Not Rated — not an F. Its 16.5-foot median from 4 readings collected 2020 is still shown as clarity, but clarity alone cannot earn a letter.

Not Rated is EPA Integrated Reporting Category 3 — insufficient information. Everything below that has been measured is still reported on this page.

Sampling is run by Illinois EPA and volunteer programs, and published through the EPA Water Quality Portal. Read the full grading methodology.

Loch Lomond Lake is a 72-acre lake in Lake County, Illinois with an estimated average depth of about 38 feet. Limited fish-species data available. Public access is available.

Source: EPA Water Quality Portal sampling records, Illinois EPA, last sampled 2020-09-19. Grade methodology: LakeQuality methodology.

What Loch Lomond Lake is good for

From access and monitoring records, not editorial picks.

  • Clear water16.5 ft of visibility

Swimming Safety

Not rated

Bacteria advisory

The letter is not a swimming clearance. Loch Lomond Lake is listed impaired under Clean Water Act §303(d) (IR 5) for nutrients (phosphorus, nitrogen), pathogens (E. coli, fecal), turbidity. Check local advisories before you swim.

Compare the safest swimming lakes near Chicago

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Water quality measurements for Loch Lomond Lake

These readings exist but are not enough for an A–F grade — see why.

Crystal clear, you can see 16.5 ft down. TSI 37.

MetricValueGrade
Water Clarity (Secchi Depth)16.5 ftNot graded
PhosphorusNo recent samples
Chlorophyll-a (Algae)No recent samples
Trophic State Index (TSI)37Oligotrophic

Low nutrients, clear water. The letter is not a swimming clearance.

Lake Details

CharacteristicValue
Maximum Depth~38 ft est.
Average Depth~11 ft est.
Surface Area72 acres
Public AccessYes

Depth marked “est.” is a modeled maximum from GLOBathy (Khazaei et al. 2022, CC0), not a measured survey. Illinois has not published bathymetry for Loch Lomond Lake.

Lake Size & Watershed

Watershed (drainage) area
1 sq mi
Shoreline
1.7 mi
Elevation
741 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.

Fishing Loch Lomond Lake

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

Nutrients (phosphorus, nitrogen)Pathogens (E. coli, fecal)Turbidity

Source: EPA ATTAINS assessment unit IL_RGU · Official waterbody report

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 Of
    Libertyville · 3.9 mi away · NPDES IL0029530
    MajorRecent violation
  • Mundelein Stp, Village Of
    Libertyville · 4 mi away · NPDES IL0022501
    MajorRecent violation
  • Lcpwd-New Century Town Wrf
    Vernon Hills · 4.9 mi away · NPDES IL0022071
    MajorRecent violation
  • University Of St Mary Of The Lake / Mundelein Seminary Stp
    Mundelein · 1 mi away · NPDES IL0024350
    Recent violation
  • Dayspring Bible College And Seminary Stp
    Mundelein · 1.2 mi away · NPDES IL0050661
    Recent violation
  • Fremont School District 79 - Stp
    Mundelein · 2.8 mi away · NPDES IL0034746
    Recent 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.

Graded lakes near Loch Lomond Lake

Loch Lomond Lake has no grade, but these lakes within a short drive do.

Nearby Lakes in Lake County

Frequently asked questions about Loch Lomond Lake

Where is Loch Lomond Lake?

Loch Lomond Lake is a lake in Lake County, Illinois. LakeQuality has not rated this lake (UNRATED) — the only measurement available is water clarity, which is not a water-quality indicator on its own — EPA's National Lakes Assessment does not grade clarity.

What is the water quality grade for Loch Lomond Lake?

Loch Lomond Lake in Lake County, Illinois is not rated for water quality — its monitoring record does not meet the evidence bar. Water clarity: 16.5 ft visibility. Surface area: 72 acres.

Is Loch Lomond Lake safe to swim in?

The letter is not a swimming clearance. Loch Lomond Lake is listed impaired under Clean Water Act §303(d) (IR 5) for nutrients (phosphorus, nitrogen), pathogens (E. coli, fecal), turbidity. Check local advisories before you swim.

How deep is Loch Lomond Lake?

No published bathymetric survey covers Loch Lomond Lake, so its depth has not been measured. The HydroLAKES global model estimates an average depth of about 38 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 72 acres.

Where this data comes from

4 measurements from 1 monitoring station, 2020. Retrieved from the EPA Water Quality Portal on 2026-08-02.

Collected and reported by

  • North American Lake Management SocietyNALMS4 samples · 2020
Monitoring station identifiers (1)

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)