Greenwood Lake
Greenwood Lake in Passaic County, New Jersey is not rated for water quality — its monitoring record does not meet the evidence bar. Water clarity: 2.1 ft visibility. Surface area: 1733 acres.
- Clarity
- 2.1 ft
- Area
- 1,733 acres
Why Greenwood Lake has no grade
We grade a lake only when its monitoring record clears the evidence bar: at least three phosphorus or chlorophyll-a samples in the last ten years, scored against EPA National Lakes Assessment thresholds for this lake’s ecoregion. For Greenwood Lake, the only measurement available is water clarity, which is not a water-quality indicator on its own — EPA's National Lakes Assessment does not grade clarity. Sampling here has recorded water clarity, but not phosphorus and algae (chlorophyll-a).
Not Rated is not an F. It is EPA Integrated Reporting Category 3 — insufficient information. The water here may be excellent or poor; nobody has measured enough of it to say. Everything below that has been measured is still reported on this page.
Sampling is run by your state environmental agency and volunteer programs, and published through the EPA Water Quality Portal. Read the full grading methodology.
Greenwood Lake is a 1,733-acre lake in Passaic County, New Jersey.
Source: EPA Water Quality Portal sampling records, your state environmental agency, last sampled 2025-10-23. Grade methodology: LakeGrade methodology.
Watch Greenwood Lake water quality
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Swimming Safety
Not ratedLimited data
Not rated for swimming — there is not enough monitoring data to judge this lake
Water quality measurements for Greenwood Lake
These readings exist but do not meet the evidence bar for an A–F grade — see why.
Very murky, less than 2.1 ft of visibility. Trophic State Index: 66.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 2.1 ft | Not graded |
| Phosphorus | No recent samples | |
| Chlorophyll-a (Algae) | No recent samples | |
| Trophic State Index (TSI) | 66 | Eutrophic |
High nutrients, frequent algae, reduced clarity
Where to stay near Greenwood Lake
Compare lakeside cabins, hotels, and vacation rentals near Greenwood 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.
Top-rated places to stay near Greenwood Lake
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Lake Details
| Characteristic | Value |
|---|---|
| Surface Area | 1,733 acres |
No bathymetric survey has been published for Greenwood Lake, so its depth is not documented here.
Fishing Greenwood Lake
Reservoir Info (USACE NID)
Greenwood 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
EPA Impairment Status
Greenwood 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 (2.7 km)
Graded lakes near Greenwood Lake
Greenwood Lake has no grade, but these lakes within a short drive do.
Nearby Lakes in Passaic County
Frequently asked questions about Greenwood Lake
Where is Greenwood Lake?
- Greenwood Lake is a lake in Passaic County, New Jersey. LakeQuality has not rated this lake (UNRATED) — there is not enough recent sampling to assign a letter.
What is the water quality grade for Greenwood Lake?
- Greenwood Lake in Passaic County, New Jersey is not rated for water quality — its monitoring record does not meet the evidence bar. Water clarity: 2.1 ft visibility. Surface area: 1733 acres.
Is Greenwood Lake safe to swim in?
- Not rated for swimming — there is not enough monitoring data to judge this lake. Greenwood Lake is not rated for water quality — its monitoring record does not meet the evidence bar. Always check local health department advisories before swimming.
Explore Greenwood Lake across LakeGrade
More New Jersey Lake Rankings
Other Lakes in New Jersey
Eutrophic Lakes in New Jersey
Where this data comes from
9 measurements from 3 monitoring stations, 2025. Retrieved from the EPA Water Quality Portal on 2026-08-21.
Collected and reported by
- Princeton Hydro LLC
PRINCETONHYDRO9 samples · 2025
Monitoring station identifiers (3)
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