Plymouth Reservoir is a 77-acre productive, nutrient-rich eutrophic lake in Chenango County, New York. Water quality is graded D based on 1 sampling years through 2020. Compared to the 6 other monitored lakes in Chenango County, Plymouth Reservoir ranks #6 for water quality.
Source: EPA Water Quality Portal sampling records, New York DNR, last sampled 2020-09-12. Grade methodology: LakeGrade methodology.
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Swimming Safety
Swimming not recommended, poor water quality with high algae risk
Water Quality Grade: D, Poor
Murky, only visible to about 6.2 ft. Trophic State Index: 51.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 6.2 ft | D |
| Phosphorus | No data | |
| Chlorophyll-a (Algae) | No data | |
| Trophic State Index (TSI) | 51 | Eutrophic |
High nutrients, frequent algae, reduced clarity
Lake Details
| Characteristic | Value |
|---|---|
| Surface Area | 77 acres |
Where to stay near Plymouth Reservoir
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Fishing Plymouth Reservoir
Location
County Ranking
Ranked #6 of 7 lakes in Chenango County
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High nutrients, frequent algae, reduced clarity
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Reservoir Info (USACE NID)
Plymouth Reservoir is a man-made reservoir impounded by the Plymouth Reservoir Dam (completed 1827), built primarily for recreation on the RESERVOIR CREEK; rockfill-type dam, 12 ft tall and 150 ft long.
- Surface area
- 77 ac
- Normal storage
- 320 ac-ft
- Max storage
- 400 ac-ft
- Drainage area
- 1.05 sq mi
- Hazard class
- Significant
- Owner
- PLYMOUTH RESERVOIR ASSOCIATION
Source: USACE National Inventory of Dams, NID ID NY01481 · Operator website
EPA Impairment Status
Plymouth Reservoir is officially listed as impaired under Clean Water Act §303(d) in the 2022 EPA reporting cycle (IR category 5).
Causes of impairment
Source: EPA ATTAINS assessment unit NY0602-0014 · Official waterbody report
Lake Size & Watershed
Size, shoreline, and watershed area from HydroLAKES (HydroSHEDS). Mean depth is a modeled estimate.
Regulated Pollution Sources Nearby
1 EPA-permitted facility operate within about 5 miles of Plymouth Reservoir under Clean Water Act (NPDES) discharge permits.
- Camp PharsaliaPharsalia · 5 mi away · NPDES NY0103781
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)
Lake size & watershed from HydroLAKES (HydroSHEDS)
Grading methodology based on Metropolitan Council standards
Most recent sample: 2020-09-12
Monitoring stations: 1