Forge Quarry Lake
Cook County, IllinoisView mapDirections
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.
- Limited data
Forge Quarry Lake in Cook County, Illinois is not rated for water quality — its monitoring record does not meet the evidence bar. Water clarity: 8.5 ft visibility.
- Clarity
- 8.5 ft
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Watch Forge Quarry Lake’s letter
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Why Forge Quarry Lake has no grade
Forge Quarry 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, Forge Quarry Lake is Not Rated — not an F. Its 8.5-foot median from 1 readings collected 2022 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.
Forge Quarry Lake is a lake in Cook County, Illinois.
Source: EPA Water Quality Portal sampling records, Illinois EPA, last sampled 2022-09-07. Grade methodology: LakeQuality methodology.
Swimming Safety
Not ratedLimited data
The letter is not a swimming clearance. Check local advisories before you swim.
Water quality measurements for Forge Quarry Lake
These readings exist but are not enough for an A–F grade — see why.
Moderate clarity, visible to about 8.5 ft. TSI 46.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 8.5 ft | Not graded |
| Phosphorus | No recent samples | |
| Chlorophyll-a (Algae) | No recent samples | |
| Trophic State Index (TSI) | 46 | Mesotrophic |
Moderate nutrients, good water quality
Fishing Forge Quarry Lake
Graded lakes near Forge Quarry Lake
Forge Quarry Lake has no grade, but these lakes within a short drive do.
Nearby Lakes in Cook County
Frequently asked questions about Forge Quarry Lake
Where is Forge Quarry Lake?
- Forge Quarry Lake is a lake in Cook County, Illinois. LakeQuality has not rated this lake (UNRATED) — no nutrient or algae measurement meets the evidence bar (at least 3 samples within 10 years).
What is the water quality grade for Forge Quarry Lake?
- Forge Quarry Lake in Cook County, Illinois is not rated for water quality — its monitoring record does not meet the evidence bar. Water clarity: 8.5 ft visibility.
Is Forge Quarry Lake safe to swim in?
- The letter is not a swimming clearance. Check local advisories before you swim.
Explore Forge Quarry Lake across LakeQuality
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Where this data comes from
1 measurement from 1 monitoring station, 2022. Retrieved from the EPA Water Quality Portal on 2026-08-02.
Collected and reported by
- USGS Illinois Water Science Center
USGS-IL1 sample · 2022
Analytical methods
- Secchi disk method
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.