By Fox Island Lake
By Fox Island Lake in Passaic County, New Jersey has a water quality grade of F (Algae-prone). Phosphorus: 39 µg/L. Chlorophyll-a (algae): 43.5 µg/L. Surface area: 1733 acres.
- Area
- 1,733 acres
- Type
- Hypereutrophic
Grade F measures nutrients and algae, not whether this is a good place for a cabin trip. Cabins and rentals near By Fox Island Lake →
By Fox Island Lake is a 1,733-acre highly nutrient-loaded hypereutrophic lake in Passaic County, New Jersey. Water quality is graded F based on 2 sampling years through 2025. Compared to the 5 other monitored lakes in Passaic County, By Fox Island Lake ranks #3 for water quality.
Source: EPA Water Quality Portal sampling records, your state environmental agency, last sampled 2025-08-19. Grade methodology: LakeGrade methodology.
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Swimming Safety
Grade onlyAlgae risk
Based on clarity and algae grades from past sampling — we do not hold live water temperature and a current cyanobacteria reading for this lake. Check your state or county health department before you swim.
Algae and nutrients are often high — check current advisories before swimming. Skip the water if you see scum or a paint-like bloom
Water Quality Grade: F (Algae-prone)
No clarity data. Phosphorus level: 39 µg/L. Chlorophyll-a: 43.5 µg/L. Trophic State Index: 62.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | No recent samples | |
| Phosphorus | 39 µg/L | Poor |
| Chlorophyll-a (Algae) | 43.5 µg/L | Poor |
| Trophic State Index (TSI) | 62 | Hypereutrophic |
Very high nutrients, dense algae, poor clarity
Where to stay near By Fox Island Lake
Compare lakeside cabins, hotels, and vacation rentals near By Fox Island Lake in Passaic 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 grade measures nutrients and algae, not lodging — cabins and rentals around By Fox Island Lake are listed below.
Top-rated places to stay near By Fox Island Lake
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Lake Details
| Characteristic | Value |
|---|---|
| Surface Area | 1,733 acres |
No bathymetric survey has been published for By Fox Island Lake, so its depth is not documented here.
Fishing By Fox Island Lake
Reservoir Info (USACE NID)
By Fox Island Lake is a man-made reservoir impounded by the Greenwood Lake Dam (completed 1928), built primarily for recreation on the Wanaque River; concrete-type dam, 17 ft tall and 270 ft long.
- Surface area
- 1,733 ac
- Normal storage
- 13,269 ac-ft
- Drainage area
- 27.1 sq mi
- Hazard class
- High
- Owner
- Division of Parks and Forestry
Source: USACE National Inventory of Dams, NID ID NJ00187 · Operator website · Matched by proximity (0.6 km)
EPA Impairment Status
By Fox Island Lake is officially listed as impaired under Clean Water Act §303(d) in the 2022 EPA reporting cycle (IR category 5).
Causes of impairment
A Total Maximum Daily Load (TMDL) plan has been approved.
Source: EPA ATTAINS assessment unit NJ02030103070030-01 · Official waterbody report · Matched by proximity (2.77 km)
County Ranking
Ranked #3 of 6 lakes in Passaic County
Nearby Lakes in Passaic County
Frequently asked questions about By Fox Island Lake
Where is By Fox Island Lake?
- By Fox Island Lake is a lake in Passaic County, New Jersey. LakeQuality grades it F for nutrients and algae. The letter is not a swimming clearance.
What is the water quality grade for By Fox Island Lake?
- By Fox Island Lake in Passaic County, New Jersey has a water quality grade of F (Algae-prone). Phosphorus: 39 µg/L. Chlorophyll-a (algae): 43.5 µg/L. Surface area: 1733 acres.
Is By Fox Island Lake safe to swim in?
- Algae and nutrients are often high — check current advisories before swimming. Skip the water if you see scum or a paint-like bloom. By Fox Island Lake has a water quality grade of F (Algae-prone). Algae concentration (chlorophyll-a) is 43.5 µg/L. Always check local health department advisories before swimming.
Explore By Fox Island Lake across LakeGrade
More New Jersey Lake Rankings
Other Grade F Lakes in New Jersey
Hypereutrophic Lakes in New Jersey
Where this data comes from
68 measurements from 1 monitoring station, 2024–2025. Retrieved from the EPA Water Quality Portal on 2026-08-21.
Collected and reported by
- Montclair State University
NJ_MSU68 samples · 2024–2025
Analytical methods
- 4500 P B ~ Phosphorus, sample preparation method
- 445.0 ~ EPA; Chlorophyll and Pheophytin in Algae by Fluorescence
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