Sepasco Lake
Dutchess County, New YorkView mapDirections
NY DEC publishes the water-quality measurements for Sepasco Lake. Here is what has been measured.
- Impaired · Nutrients (phosphorus, nitrogen)
- Limited data
Sepasco Lake in Dutchess County, New York has water-quality measurements published by NY DEC, shown here as reported. Water clarity: 8.7 ft visibility.
Sepasco Lake is a lake in Dutchess County, New York.
Source: EPA Water Quality Portal sampling records, NYSDEC, last sampled 2020-09-20. Methodology: how these readings are compared.
Swimming conditions
No readingRecreation use not supported
Nutrient and algae readings are not a swimming clearance. Sepasco Lake is listed impaired under Clean Water Act §303(d) (IR 5) for nutrients (phosphorus, nitrogen). Check local advisories before you swim.
Whether Sepasco Lake is safe to swim in today is a call for the New York Department of Environmental Conservation and the county health department, who post current advisories. LakeQuality does not issue swimming clearances.
Water quality measurements for Sepasco Lake
These are the measurements NY DEC publishes for Sepasco Lake, shown as reported. The condition class beside each reading is the EPA National Lakes Assessment class for this lake’s ecoregion.
Moderate clarity, visible to about 8.7 ft. TSI 46.
| Measure | Reading | Where it sits |
|---|---|---|
| Water clarity (Secchi depth) | 8.7ft | Measured, not scored How deep a black-and-white disk stays visible from the surface. Higher is clearer. |
| Total phosphorus | No reading The nutrient that most limits algae growth in freshwater. More phosphorus, more algae potential. | |
| Chlorophyll-a (algae) | No reading The green pigment in algae — a direct measure of how much algae is in the water. | |
| Trophic state (TSI)Carlson's 0–100 index of how much algae a lake can support, from clarity, phosphorus and chlorophyll-a. | 46 | Mesotrophic OligotrophicMesotrophicEutrophicHypereutrophic |
Moderate nutrients, good water quality
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Fishing Sepasco Lake
EPA Impairment Status
Sepasco Lake is officially listed as impaired under Clean Water Act §303(d) in the 2022 EPA reporting cycle (IR category 5).
Causes of impairment
Designated uses not supporting: Recreation.
Source: EPA ATTAINS assessment unit NY1301-0214 · Official waterbody report
Regulated Pollution Sources Nearby
9 EPA-permitted facilities operate within about 5 miles of Sepasco Lake under Clean Water Act (NPDES) discharge permits. 2 facilities have a reported Clean Water Act violation in the past three years.
- Village Of Redhook WwtpRed Hook · 3.3 mi away · NPDES NY0271420Recent violation
- Rhinebeck (V) WwtfRhinebeck · 4.8 mi away · NPDES NY0110281Recent violation
- Bard CollegeAnnandale On Hudson · 2.6 mi away · NPDES NY0031925
- Rhinebeck Mhp WwtpRhinebeck, Town Of · 2.9 mi away · NPDES NY0102172
- Eddie A Parker Youth CenterRed Hook · 2.9 mi away · NPDES NY0141925
- Rikert Commercial DevelopmentRhinebeck · 3.1 mi away · NPDES NY0148903
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.
Nearby Lakes in Dutchess County
Frequently asked questions about Sepasco Lake
Where is Sepasco Lake?
- Sepasco Lake is a lake in Dutchess County, New York. Its water-quality measurements are published by NY DEC and shown on this page as reported.
What is the water quality of Sepasco Lake?
- Sepasco Lake in Dutchess County, New York has water-quality measurements published by NY DEC, shown here as reported. Water clarity: 8.7 ft visibility.
Is Sepasco Lake safe to swim in?
- Nutrient and algae readings are not a swimming clearance. Sepasco Lake is listed impaired under Clean Water Act §303(d) (IR 5) for nutrients (phosphorus, nitrogen). Check local advisories before you swim.
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Where this data comes from
7 measurements from 1 monitoring station, 2020. Retrieved from the EPA Water Quality Portal on 2026-08-02.
Collected and reported by
- North American Lake Management Society
NALMS7 samples · 2020
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
Regulated discharger data from EPA ECHO (ICIS-NPDES)