Is Loch Lomond Lake Polluted?
Yes — Loch Lomond Lake in Lake County, Illinois is on the EPA's Clean Water Act 303(d) impaired-waters list (2024 assessment cycle). It is cited for Nutrients (phosphorus, nitrogen), Pathogens (E. coli, fecal), Turbidity. No cleanup plan (TMDL) has been completed yet. "Impaired" is a legal designation, separate from the lake's A–F water-quality grade: it means at least one designated use (such as swimming, aquatic life, or fish consumption) does not meet state standards for the listed pollutant.
EPA 303(d) Listing
| On 303(d) impaired list | Yes |
| Cleanup plan (TMDL) | Not yet written |
| Assessment cycle | 2024 |
| EPA IR category | 5 |
| Location | Lake County, Illinois |
Pollutants Cited
- Nutrients (phosphorus, nitrogen) — Excess phosphorus and nitrogen fuel algae growth and summer blooms. This is the classic agricultural-runoff and shoreline-development impairment, and the one most likely to affect swimming via blue-green algae.
- Pathogens (E. coli, fecal) — listed by EPA as exceeding water-quality standards for at least one designated use.
- Turbidity — listed by EPA as exceeding water-quality standards for at least one designated use.
Specific parameters in the EPA record: FECAL COLIFORM, PHOSPHORUS, TOTAL, TOTAL SUSPENDED SOLIDS (TSS).
What this means for using Loch Lomond Lake
Because Loch Lomond Lake is listed for Nutrients (phosphorus, nitrogen) and Pathogens (E. coli, fecal), swimming can be affected — check for posted beach advisories, especially after heavy rain or during visible algae. An impairment listing does not mean the lake is closed — most impaired lakes remain open for boating and swimming. It means a specific pollutant exceeds a standard for a specific use. Loch Lomond Lake carries an overall water-quality grade of A — see the full breakdown on the lake report. The official EPA assessment is available in the ATTAINS waterbody report.