Delaware Lake
Delaware Lake in Warren County, New Jersey has a water quality grade of F (Algae-prone). Water clarity: 1.6 ft visibility. Phosphorus: 156.5 µg/L. Chlorophyll-a (algae): 106.1 µg/L. Surface area: 38 acres.
- Clarity
- 1.6 ft
- Area
- 38 acres
- Type
- Hypereutrophic
Grade F measures nutrients and algae, not whether this is a good place for a cabin trip. Cabins and rentals near Delaware Lake →
Delaware Lake is a 38-acre highly nutrient-loaded hypereutrophic lake in Warren County, New Jersey. Water quality is graded F based on 2 sampling years through 2024. Compared to the 1 other monitored lakes in Warren County, Delaware Lake ranks #2 for water quality.
Source: EPA Water Quality Portal sampling records, your state environmental agency, last sampled 2024-09-30. 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)
Very murky, less than 1.6 ft of visibility. Phosphorus level: 156.5 µg/L. Chlorophyll-a: 106.1 µg/L. Trophic State Index: 74.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 1.6 ft | Not graded |
| Phosphorus | 156.5 µg/L | Poor |
| Chlorophyll-a (Algae) | 106.1 µg/L | Poor |
| Trophic State Index (TSI) | 74 | Hypereutrophic |
Very high nutrients, dense algae, poor clarity
Where to stay near Delaware Lake
Compare lakeside cabins, hotels, and vacation rentals near Delaware Lake in Warren 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 Delaware Lake are listed below.
Top-rated places to stay near Delaware Lake
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Lake Details
| Characteristic | Value |
|---|---|
| Surface Area | 38 acres |
No bathymetric survey has been published for Delaware Lake, so its depth is not documented here.
Fishing Delaware Lake
Reservoir Info (USACE NID)
Delaware Lake is a man-made reservoir impounded by the Delaware Lake Dam, built primarily for recreation on the Delawanna Creek; earth-type dam, 21 ft tall and 515 ft long.
- Surface area
- 38 ac
- Normal storage
- 307 ac-ft
- Drainage area
- 2.6 sq mi
- Hazard class
- Low
- Owner
- Division of Fish & Wildlife
Source: USACE National Inventory of Dams, NID ID NJ00127 · Operator website
County Ranking
Ranked #2 of 2 lakes in Warren County
Nearby Lakes in Warren County
Frequently asked questions about Delaware Lake
Where is Delaware Lake?
- Delaware Lake is a lake in Warren 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 Delaware Lake?
- Delaware Lake in Warren County, New Jersey has a water quality grade of F (Algae-prone). Water clarity: 1.6 ft visibility. Phosphorus: 156.5 µg/L. Chlorophyll-a (algae): 106.1 µg/L. Surface area: 38 acres.
Is Delaware 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. Delaware Lake has a water quality grade of F (Algae-prone). Algae concentration (chlorophyll-a) is 106.1 µg/L. Always check local health department advisories before swimming.
Explore Delaware 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
56 measurements from 2 monitoring stations, 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_BFBM56 samples · 2023–2024
Analytical methods
- Phosphorus by Colorimetry
- 445.0 ~ EPA; Chlorophyll and Pheophytin in Algae by Fluorescence
Monitoring station identifiers (2)
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.