Swimming River Reservoir
Swimming River Reservoir in Monmouth County, New Jersey has a water quality grade of C (Fair). Water clarity: 4.8 ft visibility. Phosphorus: 28.4 µg/L. Chlorophyll-a (algae): 23.4 µg/L. Surface area: 557 acres.
- Clarity
- 4.8 ft
- Area
- 557 acres
- Type
- Eutrophic
Swimming River Reservoir is a 557-acre productive, nutrient-rich eutrophic lake in Monmouth County, New Jersey. Water quality is graded C based on 2 sampling years through 2021. Compared to the 3 other monitored lakes in Monmouth County, Swimming River Reservoir ranks #3 for water quality.
Source: EPA Water Quality Portal sampling records, your state environmental agency, last sampled 2021-11-09. Grade methodology: LakeGrade methodology.
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Swimming Safety
Grade onlyBacteria advisory
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.
Swim with caution, moderate algae may be present
Water Quality Grade: C (Fair)
Murky, only visible to about 4.8 ft. Phosphorus level: 28.4 µg/L. Chlorophyll-a: 23.4 µg/L. Trophic State Index: 56.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 4.8 ft | Not graded |
| Phosphorus | 28.4 µg/L | Good |
| Chlorophyll-a (Algae) | 23.4 µg/L | Fair |
| Trophic State Index (TSI) | 56 | Eutrophic |
High nutrients, frequent algae, reduced clarity
Where to stay near Swimming River Reservoir
Compare lakeside cabins, hotels, and vacation rentals near Swimming River Reservoir in Monmouth 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 Swimming River Reservoir
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Lake Details
| Characteristic | Value |
|---|---|
| Surface Area | 557 acres |
No bathymetric survey has been published for Swimming River Reservoir, so its depth is not documented here.
Fishing Swimming River Reservoir
Reservoir Info (USACE NID)
Swimming River Reservoir is a man-made reservoir impounded by the Swimming River Reservoir Dam (completed 1901), built primarily for water supply on the Robins Swamp Brook; earth-type dam, 45 ft tall and 2,400 ft long.
- Surface area
- 557 ac
- Normal storage
- 8,000 ac-ft
- Max storage
- 14,300 ac-ft
- Drainage area
- 48.5 sq mi
- Hazard class
- High
- Owner
- New Jersey-American Water Company
Source: USACE National Inventory of Dams, NID ID NJ00082 · Operator website
EPA Impairment Status
Swimming River Reservoir 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 NJ02030104070070-01 · Official waterbody report · Matched by proximity (1.54 km)
County Ranking
Ranked #3 of 4 lakes in Monmouth County
Nearby Lakes in Monmouth County
Frequently asked questions about Swimming River Reservoir
Where is Swimming River Reservoir?
- Swimming River Reservoir is a lake in Monmouth County, New Jersey. LakeQuality grades it C for nutrients and algae. The letter is not a swimming clearance.
What is the water quality grade for Swimming River Reservoir?
- Swimming River Reservoir in Monmouth County, New Jersey has a water quality grade of C (Fair). Water clarity: 4.8 ft visibility. Phosphorus: 28.4 µg/L. Chlorophyll-a (algae): 23.4 µg/L. Surface area: 557 acres.
Is Swimming River Reservoir safe to swim in?
- Swim with caution, moderate algae may be present. Swimming River Reservoir has a water quality grade of C (Fair). Algae concentration (chlorophyll-a) is 23.4 µg/L. Always check local health department advisories before swimming.
Explore Swimming River Reservoir across LakeGrade
More New Jersey Lake Rankings
Other Grade C Lakes in New Jersey
Eutrophic Lakes in New Jersey
Where this data comes from
160 measurements from 4 monitoring stations, 2020–2021. Retrieved from the EPA Water Quality Portal on 2026-08-21.
Collected and reported by
- NJDEP Bureau of Freshwater and Biological Monitoring
NJDEP_BFBM160 samples · 2020–2021
Analytical methods
- Phosphorus by Colorimetry
- 445.0 ~ EPA; Chlorophyll and Pheophytin in Algae by Fluorescence
Monitoring station identifiers (4)
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