Cushetunk Lake
Hunterdon County, New Jersey30 acresView mapDirections
NJDEP publishes the water-quality measurements for Cushetunk Lake. Here is what has been measured.
- Eutrophic
- Impaired · Impaired biota (cause unknown)
Cushetunk Lake in Hunterdon County, New Jersey has water-quality measurements published by NJDEP, shown here as reported. Water clarity: 0.8 ft visibility. Phosphorus: 81.8 µg/L. Chlorophyll-a (algae): 27.3 µg/L. Surface area: 30 acres.
Cushetunk Lake is a 30-acre productive, nutrient-rich eutrophic lake in Hunterdon County, New Jersey. Compared to the 3 other monitored lakes in Hunterdon County, Cushetunk Lake ranks #3 for water quality.
Source: EPA Water Quality Portal sampling records, your state environmental agency, last sampled 2023-09-21. Methodology: how these readings are compared.
Swimming conditions
Readings onlyBacteria advisory
Based on clarity and algae readings from past sampling — there is no live water temperature and a current cyanobacteria reading for this lake. Check your state or county health department before you swim.
Nutrient and algae readings are not a swimming clearance. Cushetunk Lake is listed impaired under Clean Water Act §303(d) (IR 5) for impaired biota (cause unknown), nutrients (phosphorus, nitrogen), pathogens (E. coli, fecal), temperature, turbidity. Check local advisories before you swim.
Whether Cushetunk Lake is safe to swim in today is a call for the New Jersey Department of Environmental Protection and the county health department, who post current advisories. LakeQuality does not issue swimming clearances.
Water quality measurements for Cushetunk Lake
These are the measurements NJDEP publishes for Cushetunk Lake, shown as reported. The condition class beside each reading is the EPA National Lakes Assessment class for this lake’s ecoregion.
Very murky, less than 0.8 ft of visibility. Phosphorus 81.8 µg/L. Chlorophyll-a 27.3 µg/L. TSI 70.
| Measure | Reading | Where it sits |
|---|---|---|
| Water clarity (Secchi depth) | 0.8ft | Measured, not scored How deep a black-and-white disk stays visible from the surface. Higher is clearer. |
| Total phosphorus | 81.8µg/L | Measured, not scored The nutrient that most limits algae growth in freshwater. More phosphorus, more algae potential. |
| Chlorophyll-a (algae) | 27.3µg/L | Poor GoodFairPoor |
| Trophic state (TSI)Carlson's 0–100 index of how much algae a lake can support, from clarity, phosphorus and chlorophyll-a. | 70 | Eutrophic OligotrophicMesotrophicEutrophicHypereutrophic |
High nutrients, frequent algae, reduced clarity
Ask about Cushetunk Lake
Answers come straight from the public measurements and survey records on this page.
Lake Details
Surface area
30 acres
No bathymetric survey has been published for Cushetunk Lake, so its depth is not documented here.
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Stays near Cushetunk Lake
Compare lakeside cabins, hotels, and vacation rentals near Cushetunk Lake in Hunterdon County, New Jersey — live availability and prices for your trip. Switch the map to Satellite to see the lake and how close each stay is to the water. The water-quality readings cover nutrients and algae, not lodging. Cabins and rentals around Cushetunk Lake are listed below.
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Fishing Cushetunk Lake
Reservoir Info (USACE NID)
Cushetunk Lake is a man-made reservoir impounded by the Lake Cushetunk Dam (completed 1928), built primarily for recreation on the South Branch Rockaway Creek; earth-type dam, 20 ft tall and 594 ft long.
- Surface area
- 30 ac
- Normal storage
- 212 ac-ft
- Max storage
- 365 ac-ft
- Drainage area
- 12.5 sq mi
- Hazard class
- Significant
- Owner
- Township of Readington
Source: USACE National Inventory of Dams, NID ID NJ00347 · Operator website
EPA Impairment Status
Cushetunk 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: Aquatic life, Recreation.
A Total Maximum Daily Load (TMDL) plan has been approved.
Source: EPA ATTAINS assessment unit NJ02030105050100-01 · Official waterbody report
Nearby Lakes in Hunterdon County
Frequently asked questions about Cushetunk Lake
Where is Cushetunk Lake?
- Cushetunk Lake is a lake in Hunterdon County, New Jersey. Its water-quality measurements are published by NJDEP and shown on this page as reported.
What is the water quality of Cushetunk Lake?
- Cushetunk Lake in Hunterdon County, New Jersey has water-quality measurements published by NJDEP, shown here as reported. Water clarity: 0.8 ft visibility. Phosphorus: 81.8 µg/L. Chlorophyll-a (algae): 27.3 µg/L. Surface area: 30 acres.
Is Cushetunk Lake safe to swim in?
- Nutrient and algae readings are not a swimming clearance. Cushetunk Lake is listed impaired under Clean Water Act §303(d) (IR 5) for impaired biota (cause unknown), nutrients (phosphorus, nitrogen), pathogens (E. coli, fecal), temperature, turbidity. Check local advisories before you swim.
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Where this data comes from
77 measurements from 3 monitoring stations, 2022–2023. Retrieved from the EPA Water Quality Portal on 2026-08-21.
Collected and reported by
- NJDEP Bureau of Freshwater and Biological Monitoring
NJDEP_BFBM77 samples · 2022–2023
Analytical methods
- Phosphorus by Colorimetry
- 445.0 ~ EPA; Chlorophyll and Pheophytin in Algae by Fluorescence
Monitoring station identifiers (3)
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