Cupsaw Lake
Cupsaw Lake in Passaic County, New Jersey is not rated for water quality — its monitoring record does not meet the evidence bar. Water clarity: 4.3 ft visibility. Surface area: 69 acres.
- Clarity
- 4.3 ft
- Area
- 69 acres
Why Cupsaw 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 Cupsaw Lake, no nutrient or algae measurement meets the evidence bar (at least 3 samples within 10 years). 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.
Cupsaw Lake is a 69-acre lake in Passaic County, New Jersey.
Source: EPA Water Quality Portal sampling records, your state environmental agency, last sampled 2022-06-21. Grade methodology: LakeGrade methodology.
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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 Cupsaw Lake
These readings exist but do not meet the evidence bar for an A–F grade — see why.
Murky, only visible to about 4.3 ft. Trophic State Index: 56.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 4.3 ft | Not graded |
| Phosphorus | No recent samples | |
| Chlorophyll-a (Algae) | No recent samples | |
| Trophic State Index (TSI) | 56 | Eutrophic |
High nutrients, frequent algae, reduced clarity
Where to stay near Cupsaw Lake
Compare lakeside cabins, hotels, and vacation rentals near Cupsaw 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 Cupsaw Lake
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Lake Details
| Characteristic | Value |
|---|---|
| Surface Area | 69 acres |
No bathymetric survey has been published for Cupsaw Lake, so its depth is not documented here.
Fishing Cupsaw Lake
Reservoir Info (USACE NID)
Cupsaw Lake is a man-made reservoir impounded by the Cupsaw Lake Dam (completed 1930), built primarily for recreation on the Cupsaw Brook; earth-type dam, 35 ft tall and 430 ft long.
- Surface area
- 69 ac
- Normal storage
- 698 ac-ft
- Drainage area
- 4.2 sq mi
- Hazard class
- High
- Owner
- Cupsaw Lake Inprovement Association
Source: USACE National Inventory of Dams, NID ID NJ00194 · Operator website
Graded lakes near Cupsaw Lake
Cupsaw Lake has no grade, but these lakes within a short drive do.
Nearby Lakes in Passaic County
Frequently asked questions about Cupsaw Lake
Where is Cupsaw Lake?
- Cupsaw 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 Cupsaw Lake?
- Cupsaw Lake in Passaic County, New Jersey is not rated for water quality — its monitoring record does not meet the evidence bar. Water clarity: 4.3 ft visibility. Surface area: 69 acres.
Is Cupsaw Lake safe to swim in?
- Not rated for swimming — there is not enough monitoring data to judge this lake. Cupsaw 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 Cupsaw Lake across LakeGrade
More New Jersey Lake Rankings
Other Lakes in New Jersey
Eutrophic Lakes in New Jersey
Where this data comes from
1 measurement from 1 monitoring station, 2022. Retrieved from the EPA Water Quality Portal on 2026-08-21.
Collected and reported by
- North American Lake Management Society
NALMS1 sample · 2022
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.