Seven Hills Lake
Putnam County, New York56 acresView mapDirections
Not Rated: one monitoring station are on record, but they measured water clarity only. LakeQuality’s A–F method grades total phosphorus, total nitrogen, chlorophyll-a, and turbidity; clarity is shown, not scored.
- Impaired · Mercury
- 36 ft max depth
- Public access
- Limited data
Seven Hills Lake in Putnam County, New York is not rated for water quality — its monitoring record does not meet the evidence bar. Water clarity: 4.8 ft visibility. Surface area: 56 acres.
- Clarity
- 4.8 ft
- Max depth
- ~36 ft est.
- Area
- 56 acres
- Public access
- Yes
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Watch Seven Hills Lake’s letter
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Why Seven Hills Lake has no grade
Seven Hills Lake has monitoring on record from one station, but only water clarity was measured. LakeQuality’s A–F letter uses total phosphorus, total nitrogen, chlorophyll-a, and turbidity against EPA National Lakes Assessment condition classes. With none of those grading measurements on record, Seven Hills Lake is Not Rated — not an F. Its 4.8-foot median from 8 readings collected 2020 is still shown as clarity, but clarity alone cannot earn a letter.
Not Rated is EPA Integrated Reporting Category 3 — insufficient information. Everything below that has been measured is still reported on this page.
Sampling is run by NYSDEC and volunteer programs, and published through the EPA Water Quality Portal. Read the full grading methodology.
Seven Hills Lake is a 56-acre lake in Putnam County, New York with an estimated average depth of about 36 feet. Limited fish-species data available. Public access is available.
Source: EPA Water Quality Portal sampling records, NYSDEC, last sampled 2020-09-14. Grade methodology: LakeQuality methodology.
Swimming Safety
Not ratedLimited data
The letter is not a swimming clearance. Seven Hills Lake is listed impaired under Clean Water Act §303(d) (IR 4A) for mercury, nutrients (phosphorus, nitrogen). Check local advisories before you swim.
Water quality measurements for Seven Hills Lake
These readings exist but are not enough for an A–F grade — see why.
Murky, only visible to about 4.8 ft. TSI 54.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 4.8 ft | Not graded |
| Phosphorus | No recent samples | |
| Chlorophyll-a (Algae) | No recent samples | |
| Trophic State Index (TSI) | 54 | Eutrophic |
High nutrients, frequent algae, reduced clarity
Lake Details
| Characteristic | Value |
|---|---|
| Maximum Depth | ~36 ft est. |
| Average Depth | ~21 ft est. |
| Surface Area | 56 acres |
| Public Access | Yes |
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 Seven Hills Lake.
Lake Size & Watershed
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.
Fishing Seven Hills Lake
Reservoir Info (USACE NID)
Seven Hills Lake is a man-made reservoir impounded by the Seven Hills Realty CO INC Dam (completed 1957), built primarily for recreation on the TR-W BRANCH CROTON RIVER; earth-type dam, 15 ft tall and 345 ft long.
- Surface area
- 56 ac
- Normal storage
- 380 ac-ft
- Max storage
- 570 ac-ft
- Drainage area
- 5.5 sq mi
- Hazard class
- Low
- Owner
- NYCDEP DAMS EAST OF THE HUDSON RIVER;SEVEN HILLS LAKE PROPERTY OWNERS ASSOC.
Source: USACE National Inventory of Dams, NID ID NY01143 · Operator website · Matched by proximity (0.62 km)
EPA Impairment Status
Seven Hills 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 NY1302-0045 · Official waterbody report · Matched by proximity (2.91 km)
Regulated Pollution Sources Nearby
3 EPA-permitted facilities operate within about 5 miles of Seven Hills Lake under Clean Water Act (NPDES) discharge permits. 1 facility has a reported Clean Water Act violation in the past three years.
- Package Pavement CompanyStormville · 3.5 mi away · NPDES NY0087840Recent violation
- Carmel Sch Dist Bus GaragePatterson · 2.3 mi away · NPDES NY0264466
- Camp Edward Isaacs StfEast Fishkill · 4.1 mi away · NPDES NY0101974
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 Putnam County
Frequently asked questions about Seven Hills Lake
Where is Seven Hills Lake?
- Seven Hills Lake is a lake in Putnam County, New York. LakeQuality has not rated this lake (UNRATED) — the only measurement available is water clarity, which is not a water-quality indicator on its own — EPA's National Lakes Assessment does not grade clarity.
What is the water quality grade for Seven Hills Lake?
- Seven Hills Lake in Putnam County, New York is not rated for water quality — its monitoring record does not meet the evidence bar. Water clarity: 4.8 ft visibility. Surface area: 56 acres.
Is Seven Hills Lake safe to swim in?
- The letter is not a swimming clearance. Seven Hills Lake is listed impaired under Clean Water Act §303(d) (IR 4A) for mercury, nutrients (phosphorus, nitrogen). Check local advisories before you swim.
How deep is Seven Hills Lake?
- No published bathymetric survey covers Seven Hills Lake, so its depth has not been measured. The HydroLAKES global model estimates an average depth of about 36 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 56 acres.
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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)
Grade thresholds from the EPA National Lakes Assessment (EPA 841-R-24-006, Table 6-3), applied by ecoregion. See how grades are calculated 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)