Pataganset Lake
New London County, Connecticut120 acresView mapDirections
CT DEEP publishes the water-quality measurements for Pataganset Lake. Here is what has been measured.
- Mesotrophic
- Limited data
Pataganset Lake in New London County, Connecticut has water-quality measurements published by CT DEEP, shown here as reported. Phosphorus: 20 µg/L. Chlorophyll-a (algae): 7.6 µg/L. Surface area: 120 acres.
Pataganset Lake is a 120-acre mesotrophic lake in New London County, Connecticut. Compared to the 9 other monitored lakes in New London County, Pataganset Lake ranks #9 for water quality.
Source: EPA Water Quality Portal sampling records, your state environmental agency, last sampled 2023-07-27. Methodology: how these readings are compared.
Swimming conditions
Readings onlyLimited data
Based on clarity and algae readings from past sampling — there is no live water temperature and a current cyanobacteria reading for this lake. Check your state or county health department before you swim.
Nutrient and algae readings are not a swimming clearance. Check local advisories before you swim.
Whether Pataganset Lake is safe to swim in today is a call for the Connecticut Department of Energy and Environmental Protection and the county health department, who post current advisories. LakeQuality does not issue swimming clearances.
Water quality measurements for Pataganset Lake
These are the measurements CT DEEP publishes for Pataganset Lake, shown as reported. The condition class beside each reading is the EPA National Lakes Assessment class for this lake’s ecoregion.
No clarity data. Phosphorus 20 µg/L. Chlorophyll-a 7.6 µg/L. TSI 49.
| Measure | Reading | Where it sits |
|---|---|---|
| Water clarity (Secchi depth) | No reading How deep a black-and-white disk stays visible from the surface. Higher is clearer. | |
| Total phosphorus | 20µg/L | Fair GoodFairPoor |
| Chlorophyll-a (algae) | 7.6µg/L | Measured, not scored The green pigment in algae — a direct measure of how much algae is in the water. |
| Trophic state (TSI)Carlson's 0–100 index of how much algae a lake can support, from clarity, phosphorus and chlorophyll-a. | 49 | Mesotrophic OligotrophicMesotrophicEutrophicHypereutrophic |
Moderate nutrients, good water quality
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Lake Details
Surface area
120 acres
No bathymetric survey has been published for Pataganset Lake, so its depth is not documented here.
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Fishing Pataganset Lake
Reservoir Info (USACE NID)
Pataganset Lake is a man-made reservoir impounded by the Pataguanset Lake Dam (completed 1942), built primarily for recreation on the Pataguanset River; earth-type dam, 12 ft tall and 210 ft long.
- Surface area
- 120 ac
- Normal storage
- 310 ac-ft
- Max storage
- 950 ac-ft
- Drainage area
- 3.91 sq mi
- Hazard class
- High
- Owner
- Connecticut DEEP
Source: USACE National Inventory of Dams, NID ID CT00159 · Operator website · Matched by proximity (0.56 km)
Nearby Lakes in New London County
Frequently asked questions about Pataganset Lake
Where is Pataganset Lake?
- Pataganset Lake is a lake in New London County, Connecticut. Its water-quality measurements are published by CT DEEP and shown on this page as reported.
What is the water quality of Pataganset Lake?
- Pataganset Lake in New London County, Connecticut has water-quality measurements published by CT DEEP, shown here as reported. Phosphorus: 20 µg/L. Chlorophyll-a (algae): 7.6 µg/L. Surface area: 120 acres.
Is Pataganset Lake safe to swim in?
- Nutrient and algae readings are not a swimming clearance. Check local advisories before you swim.
Explore Pataganset Lake across LakeQuality
More lakes in Connecticut
Other Lakes in Connecticut
Mesotrophic Lakes in Connecticut
Where this data comes from
10 measurements from 1 monitoring station, 2023. Retrieved from the EPA Water Quality Portal on 2026-08-21.
Collected and reported by
- Connecticut Department Of Energy And Environmental Protection
CT_DEP01_WQX10 samples · 2023
Analytical methods
- Total Phosphorus After Block Digestion
- 445.0 ~ EPA; Chlorophyll and Pheophytin in Algae by Fluorescence
- Nitrate-Nitrite Nitrogen by Colorimetry
- Turbidity by Nephelometry
Monitoring station identifiers (1)
EPA condition classes from the National Lakes Assessment (EPA 841-R-24-006, Table 6-3), applied by ecoregion. See where the data comes from and data sources.