Winnebago Lake
Morris County, New JerseyView mapDirections
NJDEP publishes the water-quality measurements for Winnebago Lake. Here is what has been measured.
- Eutrophic
- Impaired · Metals (other than mercury)
- Limited data
Winnebago Lake in Morris County, New Jersey has water-quality measurements published by NJDEP, shown here as reported. Water clarity: 3.8 ft visibility. Phosphorus: 50.9 µg/L. Chlorophyll-a (algae): 26.3 µg/L.
Winnebago Lake is a productive, nutrient-rich eutrophic lake in Morris County, New Jersey. Compared to the 11 other monitored lakes in Morris County, Winnebago Lake ranks #7 for water quality.
Source: EPA Water Quality Portal sampling records, your state environmental agency, last sampled 2024-11-26. Methodology: how these readings are compared.
Swimming conditions
Readings onlyLimited data
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. Winnebago Lake is listed impaired under Clean Water Act §303(d) (IR 5) for metals (other than mercury), oxygen depletion (low DO), temperature. Check local advisories before you swim.
Whether Winnebago 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 Winnebago Lake
These are the measurements NJDEP publishes for Winnebago 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 3.8 ft. Phosphorus 50.9 µg/L. Chlorophyll-a 26.3 µg/L. TSI 60.
| Measure | Reading | Where it sits |
|---|---|---|
| Water clarity (Secchi depth) | 3.8ft | Measured, not scored How deep a black-and-white disk stays visible from the surface. Higher is clearer. |
| Total phosphorus | 50.9µg/L | Poor GoodFairPoor |
| Chlorophyll-a (algae) | 26.3µg/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. | 60 | Eutrophic OligotrophicMesotrophicEutrophicHypereutrophic |
High nutrients, frequent algae, reduced clarity
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Stays near Winnebago Lake
Compare lakeside cabins, hotels, and vacation rentals near Winnebago Lake in Morris 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 Winnebago Lake are listed below.
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Fishing Winnebago Lake
EPA Impairment Status
Winnebago 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.
A Total Maximum Daily Load (TMDL) plan has been approved.
Source: EPA ATTAINS assessment unit NJ02030103050050-01 · Official waterbody report
Nearby Lakes in Morris County
Frequently asked questions about Winnebago Lake
Where is Winnebago Lake?
- Winnebago Lake is a lake in Morris County, New Jersey. Its water-quality measurements are published by NJDEP and shown on this page as reported.
What is the water quality of Winnebago Lake?
- Winnebago Lake in Morris County, New Jersey has water-quality measurements published by NJDEP, shown here as reported. Water clarity: 3.8 ft visibility. Phosphorus: 50.9 µg/L. Chlorophyll-a (algae): 26.3 µg/L.
Is Winnebago Lake safe to swim in?
- Nutrient and algae readings are not a swimming clearance. Winnebago Lake is listed impaired under Clean Water Act §303(d) (IR 5) for metals (other than mercury), oxygen depletion (low DO), temperature. Check local advisories before you swim.
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Where this data comes from
26 measurements from 1 monitoring station, 2023–2024. Retrieved from the EPA Water Quality Portal on 2026-08-21.
Collected and reported by
- NJDEP Bureau of Freshwater and Biological Monitoring
NJDEP_BFBM26 samples · 2023–2024
Analytical methods
- Phosphorus by Colorimetry
- 445.0 ~ EPA; Chlorophyll and Pheophytin in Algae by Fluorescence
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