Sleepy Hollow Lake
Greene County, New York324 acresView mapDirections
NY DEC publishes the water-quality measurements for Sleepy Hollow Lake. Here is what has been measured.
- Impaired · Nutrients (phosphorus, nitrogen)
- 57 ft max depth
- Limited data
Sleepy Hollow Lake in Greene County, New York has water-quality measurements published by NY DEC, shown here as reported. Water clarity: 5.9 ft visibility. Surface area: 324 acres.
Sleepy Hollow Lake is a 324-acre lake in Greene County, New York with an estimated average depth of about 57 feet.
Source: EPA Water Quality Portal sampling records, NYSDEC, last sampled 2020-09-22. Methodology: how these readings are compared.
Sleepy Hollow Lake covers about 320 acres in Greene County. For a place on the water, look through cabin and lake-house rentals near Sleepy Hollow Lake on Vrbo. For a hotel or motel room, Booking.com and Expedia both search around the lake.
Swimming conditions
No readingRecreation use not supported
Nutrient and algae readings are not a swimming clearance. Sleepy Hollow Lake is listed impaired under Clean Water Act §303(d) (IR 5) for nutrients (phosphorus, nitrogen). Check local advisories before you swim.
Whether Sleepy Hollow 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 Sleepy Hollow Lake
These are the measurements NY DEC publishes for Sleepy Hollow Lake, shown as reported. The condition class beside each reading is the EPA National Lakes Assessment class for this lake’s ecoregion.
Murky, only visible to about 5.9 ft. TSI 52.
| Measure | Reading | Where it sits |
|---|---|---|
| Water clarity (Secchi depth) | 5.9ft | 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. | 52 | Eutrophic OligotrophicMesotrophicEutrophicHypereutrophic |
High nutrients, frequent algae, reduced clarity
Ask about Sleepy Hollow Lake
Answers come straight from the public measurements and survey records on this page.
Lake Details
Max depth
~57 ft est.
Surface area
324 acres
Depth marked “est.” is a modeled maximum from GLOBathy (Khazaei et al. 2022, CC0), not a measured survey. New York has not published bathymetry for Sleepy Hollow Lake.
Lake Size & Watershed
Watershed (drainage) area
9 sq mi
HydroLAKES / HydroSHEDS
Shoreline
6.2 mi
HydroLAKES / HydroSHEDS
Elevation
69 ft
Size, shoreline, and watershed area from HydroLAKES (HydroSHEDS). Mean depth here is modelled, not surveyed — HydroLAKES v1.0 estimates lake depth from surrounding terrain rather than from soundings. Treat it as an approximation, and prefer a state bathymetric survey where one exists.
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Stays near Sleepy Hollow Lake
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Fishing Sleepy Hollow Lake
Reservoir Info (USACE NID)
Sleepy Hollow Lake is a man-made reservoir impounded by the Sleepy Hollow Dam (completed 1972), built primarily for recreation on the MURDERERS CREEK; earth-type dam, 83 ft tall and 753 ft long.
- Surface area
- 324 ac
- Normal storage
- 8,400 ac-ft
- Max storage
- 13,500 ac-ft
- Drainage area
- 13.3 sq mi
- Hazard class
- High
- Owner
- ASSOC OF PROPERTY OWNERS OF SLEEPY HOLLOW LAKE, INC.
All listed purposes: Recreation;Water Supply.
Source: USACE National Inventory of Dams, NID ID NY00142 · Operator website
EPA Impairment Status
Sleepy Hollow 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 NY1301-0059 · Official waterbody report
Regulated Pollution Sources Nearby
22 EPA-permitted facilities operate within about 5 miles of Sleepy Hollow Lake under Clean Water Act (NPDES) discharge permits, including 4 classified by the EPA as major dischargers. 11 facilities have a reported Clean Water Act violation in the past three years.
- Hudson (C) StpHudson · 2.5 mi away · NPDES NY0022039MajorRecent violation
- Town Of Greenport StpHudson · 3.4 mi away · NPDES NY0030988MajorRecent violation
- Coxsackie (V) StpCoxsackie · 3.9 mi away · NPDES NY0033545MajorRecent violation
- New Athens Generating Co, LlcAthens · 4 mi away · NPDES NY0261009MajorRecent violation
- Sleepy Hollow Lake StpAthens · 1.1 mi away · NPDES NY0025291Recent violation
- Brick Row StpAthens · 1.3 mi away · NPDES NY0020877Recent violation
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 Greene County
Frequently asked questions about Sleepy Hollow Lake
Where is Sleepy Hollow Lake?
- Sleepy Hollow Lake is a lake in Greene 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 Sleepy Hollow Lake?
- Sleepy Hollow Lake in Greene County, New York has water-quality measurements published by NY DEC, shown here as reported. Water clarity: 5.9 ft visibility. Surface area: 324 acres.
Is Sleepy Hollow Lake safe to swim in?
- Nutrient and algae readings are not a swimming clearance. Sleepy Hollow Lake is listed impaired under Clean Water Act §303(d) (IR 5) for nutrients (phosphorus, nitrogen). Check local advisories before you swim.
How deep is Sleepy Hollow Lake?
- No published bathymetric survey covers Sleepy Hollow Lake, so its depth has not been measured. The HydroLAKES global model estimates an average depth of about 57 feet, but that is a modelled estimate derived from surrounding terrain rather than a measurement on the water, so treat it as approximate. The lake covers 324 acres.
Explore Sleepy Hollow Lake across LakeQuality
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Where this data comes from
8 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
NALMS8 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)
Lake size & watershed from HydroLAKES (HydroSHEDS)