Forest Lake is a mesotrophic lake in Rensselaer County, New York. Water quality is graded C based on 1 sampling years through 2020. Limited fish-species data available. Public access is available. Compared to the 6 other monitored lakes in Rensselaer County, Forest Lake ranks #4 for water quality.
Source: EPA Water Quality Portal sampling records, New York DNR, last sampled 2020-09-06. Grade methodology: LakeGrade methodology.
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Swimming Safety
Generally safe for swimming, moderate water quality
Water Quality Grade: C, Fair
Moderate clarity, visible to about 8.4 ft. Trophic State Index: 46.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 8.4 ft | C |
| Phosphorus | No data | |
| Chlorophyll-a (Algae) | No data | |
| Trophic State Index (TSI) | 46 | Mesotrophic |
Moderate nutrients, good water quality
Where to stay near Forest Lake
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Fishing Forest Lake
Location
County Ranking
Ranked #4 of 7 lakes in Rensselaer County
Nearby Lakes in Rensselaer County
Explore Forest Lake across LakeGrade
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Species activity outlook by water temperature and season
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Moderate nutrients, good water quality
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EPA Impairment Status
Forest Lake is officially listed as impaired under Clean Water Act §303(d) in the 2022 EPA reporting cycle (IR category 4A).
Causes of impairment
A Total Maximum Daily Load (TMDL) plan has been approved.
Source: EPA ATTAINS assessment unit NY1301-0262 · Official waterbody report · Matched by proximity (2.78 km)
Regulated Pollution Sources Nearby
2 EPA-permitted facilities operate within about 5 miles of Forest Lake under Clean Water Act (NPDES) discharge permits. 1 facility has a reported Clean Water Act violation in the past three years.
- Grafton QuarryGrafton · 3.8 mi away · NPDES NY0261025Recent violation
- Fane Cropseyville QuarryBrunswick · 4.3 mi away · NPDES NY0223794
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)
Grading methodology based on Metropolitan Council standards
Most recent sample: 2020-09-06
Monitoring stations: 1