Northdeep Lake
Chautauqua County, New YorkLimited DataMesotrophic
Northdeep Lake is a mesotrophic lake in Chautauqua County, New York. Water quality is graded C based on 1 sampling years through 2025. Compared to the 15 other monitored lakes in Chautauqua County, Northdeep Lake ranks #6 for water quality.
Source: EPA Water Quality Portal sampling records, New York DNR, last sampled 2025-05-08. 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 7.1 ft. Trophic State Index: 49.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 7.1 ft | C |
| Phosphorus | No data | |
| Chlorophyll-a (Algae) | No data | |
| Trophic State Index (TSI) | 49 | Mesotrophic |
Moderate nutrients, good water quality
Location
County Ranking
Ranked #6 of 16 lakes in Chautauqua County
Nearby Lakes in Chautauqua County
More New York Lake Rankings
Other Grade C Lakes in New York
Mesotrophic Lakes in New York
EPA Impairment Status
Northdeep 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 NY0202-0072 · Official waterbody report · Matched by proximity (1.37 km)
Data Sources
Water quality data from the EPA Water Quality Portal
Impairment status from EPA ATTAINS 303(d) database
Grading methodology based on Metropolitan Council standards
Most recent sample: 2025-05-08
Monitoring stations: 1