West Loon Lake
Lake County, IllinoisView mapDirections
Illinois EPA publishes the water-quality measurements for West Loon Lake. Here is what has been measured.
- Eutrophic
- Impaired · Mercury
- Limited data
Ask about West Loon Lake
Answers come straight from the public measurements and survey records on this page.
West Loon Lake in Lake County, Illinois has water-quality measurements published by Illinois EPA, shown here as reported. Chlorophyll-a (algae): 9.3 µg/L.
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West Loon Lake is a productive, nutrient-rich eutrophic lake in Lake County, Illinois. Compared to the 18 other monitored lakes in Lake County, West Loon Lake ranks #8 for water quality.
Source: EPA Water Quality Portal sampling records, Illinois EPA, last sampled 2022-08-10. Grade methodology: LakeQuality methodology.
Swimming conditions
Readings onlyLimited data
Based on clarity and algae readings from past sampling — there is no live water temperature and a current cyanobacteria reading for this lake. Check your state or county health department before you swim.
Nutrient and algae readings are not a swimming clearance. West Loon Lake is listed impaired under Clean Water Act §303(d) (IR 5) for mercury. Check local advisories before you swim.
Whether West Loon Lake is safe to swim in today is a call for the Illinois Environmental Protection Agency and the county health department, who post current advisories. LakeQuality does not issue swimming clearances.
Water quality measurements for West Loon Lake
These are the measurements Illinois EPA publishes for West Loon Lake, shown as reported. The condition class beside each reading is the EPA National Lakes Assessment class for this lake’s ecoregion.
No clarity data. Chlorophyll-a 9.3 µg/L. TSI 53.
| Metric | Value | EPA condition class |
|---|---|---|
| Water Clarity (Secchi Depth) | No recent samples | |
| Phosphorus | No recent samples | |
| Chlorophyll-a (Algae) | 9.3 µg/L | Good |
| Trophic State Index (TSI) | 53 | Eutrophic |
High nutrients, frequent algae, reduced clarity
Fishing West Loon Lake
EPA Impairment Status
West Loon 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_RTZB · Official waterbody report
Nearby Lakes in Lake County
Frequently asked questions about West Loon Lake
Where is West Loon Lake?
- West Loon Lake is a lake in Lake County, Illinois. Its water-quality measurements are published by Illinois EPA and shown on this page as reported.
What is the water quality of West Loon Lake?
- West Loon Lake in Lake County, Illinois has water-quality measurements published by Illinois EPA, shown here as reported. Chlorophyll-a (algae): 9.3 µg/L.
Is West Loon Lake safe to swim in?
- Nutrient and algae readings are not a swimming clearance. West Loon Lake is listed impaired under Clean Water Act §303(d) (IR 5) for mercury. Check local advisories before you swim.
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Where this data comes from
8 measurements from 1 monitoring station, 2022. Retrieved from the EPA Water Quality Portal on 2026-08-02.
Collected and reported by
- illinois epa
IL_EPA_WQX8 samples · 2022
Analytical methods
- 10200 H 2 ~ Chlorophyll a-b-c Determination by spectrophotometer
Monitoring station identifiers (1)
EPA condition classes from the National Lakes Assessment (EPA 841-R-24-006, Table 6-3), applied by ecoregion. See where the data comes from and data sources.
Other records on this page
Impairment status from EPA ATTAINS 303(d) database