South End Lake
Sussex County, New JerseyView mapDirections
NJDEP publishes the water-quality measurements for South End Lake. Here is what has been measured.
- Eutrophic
- Impaired · Impaired biota (cause unknown)
- Limited data
South End Lake in Sussex County, New Jersey has water-quality measurements published by NJDEP, shown here as reported. Water clarity: 4.4 ft visibility. Phosphorus: 30 µg/L.
South End Lake is a productive, nutrient-rich eutrophic lake in Sussex County, New Jersey. Compared to the 17 other monitored lakes in Sussex County, South End Lake ranks #7 for water quality.
Source: EPA Water Quality Portal sampling records, your state environmental agency, last sampled 2020-10-28. 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. South End Lake is listed impaired under Clean Water Act §303(d) (IR 5) for impaired biota (cause unknown), metals (other than mercury), pathogens (E. coli, fecal), temperature. Check local advisories before you swim.
Whether South End 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 South End Lake
These are the measurements NJDEP publishes for South End 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 4.4 ft. Phosphorus 30 µg/L. TSI 54.
| Measure | Reading | Where it sits |
|---|---|---|
| Water clarity (Secchi depth) | 4.4ft | Measured, not scored How deep a black-and-white disk stays visible from the surface. Higher is clearer. |
| Total phosphorus | 30µg/L | Poor GoodFairPoor |
| 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. | 54 | Eutrophic OligotrophicMesotrophicEutrophicHypereutrophic |
High nutrients, frequent algae, reduced clarity
Ask about South End Lake
Answers come straight from the public measurements and survey records on this page.
Stays via Stay22
Stays near South End Lake
Compare lakeside cabins, hotels, and vacation rentals near South End Lake in Sussex 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 South End Lake are listed below.
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Fishing South End Lake
Reservoir Info (USACE NID)
South End Lake is a man-made reservoir impounded by the West Shore Trail Dam on the Wallkill River; earth-type dam.
- Hazard class
- High
- Owner
- Estate of Bernard A. Handler
Source: USACE National Inventory of Dams, NID ID NJ01018 · Operator website · Matched by proximity (0.4 km)
EPA Impairment Status
South End 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: Drinking water, Aquatic life, Recreation.
A Total Maximum Daily Load (TMDL) plan has been approved.
Source: EPA ATTAINS assessment unit NJ02020007010010-01 · Official waterbody report
Nearby Lakes in Sussex County
Frequently asked questions about South End Lake
Where is South End Lake?
- South End Lake is a lake in Sussex County, New Jersey. Its water-quality measurements are published by NJDEP and shown on this page as reported.
What is the water quality of South End Lake?
- South End Lake in Sussex County, New Jersey has water-quality measurements published by NJDEP, shown here as reported. Water clarity: 4.4 ft visibility. Phosphorus: 30 µg/L.
Is South End Lake safe to swim in?
- Nutrient and algae readings are not a swimming clearance. South End Lake is listed impaired under Clean Water Act §303(d) (IR 5) for impaired biota (cause unknown), metals (other than mercury), pathogens (E. coli, fecal), temperature. Check local advisories before you swim.
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Where this data comes from
19 measurements from 1 monitoring station, 2020. Retrieved from the EPA Water Quality Portal on 2026-08-21.
Collected and reported by
- Princeton Hydro LLC
PRINCETONHYDRO19 samples · 2020
Analytical methods
- 4500 P B ~ Phosphorus, sample preparation method
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