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LakeQuality

Pattagansett Lake

New London County, Connecticut120 acresView mapDirections

CT DEEP publishes the water-quality measurements for Pattagansett Lake. Here is what has been measured.

Clarity
6.8 ft
Typical for Connecticut
Secchi · sampled 2025
Area
120 acres
Surface area
  • Public access
  • Limited data

Pattagansett Lake in New London County, Connecticut has water-quality measurements published by CT DEEP, shown here as reported. Water clarity: 6.8 ft visibility. Surface area: 120 acres.

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Pattagansett Lake is a 120-acre lake in New London County, Connecticut. Limited fish-species data available. Public access is available with 1 public boat landing.

Source: EPA Water Quality Portal sampling records, your state environmental agency, last sampled 2025-09-05. Methodology: how these readings are compared.

What Pattagansett Lake is good for

From access and monitoring records, not editorial picks.

  • Boat launch1 documented ramp

Swimming conditions

No reading

Limited data

Nutrient and algae readings are not a swimming clearance. Check local advisories before you swim.

Whether Pattagansett 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.

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Water quality measurements for Pattagansett Lake

These are the measurements CT DEEP publishes for Pattagansett Lake, shown as reported. The condition class beside each reading is the EPA National Lakes Assessment class for this lake’s ecoregion.

Moderate clarity, visible to about 6.8 ft. TSI 49.

Water quality readings
MeasureReadingWhere it sits
Water clarity (Secchi depth)6.8ftMeasured, not scored

How deep a black-and-white disk stays visible from the surface. Higher is clearer.

Total phosphorusNo reading

The nutrient that most limits algae growth in freshwater. More phosphorus, more algae potential.

Chlorophyll-a (algae)No reading

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.49Mesotrophic
OligotrophicMesotrophicEutrophicHypereutrophic

Moderate nutrients, good water quality

Ask about Pattagansett Lake

Answers come straight from the public measurements and survey records on this page.

Lake Details

Surface area

120 acres

Public access

Yes

Listed by CT DEEP

No bathymetric survey has been published for Pattagansett Lake, so its depth is not documented here.

Recreation & Access

1
Boat Landings
Yes
Public Access
  • Pattagansett LakePublic

Named access points in the USGS National Boat Ramps inventory, within about 3 miles. More lakes with boat ramps

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Stays near Pattagansett Lake

Compare lakeside cabins, hotels, and vacation rentals near Pattagansett Lake in New London County, Connecticut — 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.

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Fishing Pattagansett Lake

Reservoir Info (USACE NID)

Pattagansett 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

Nearby Lakes in New London County

Frequently asked questions about Pattagansett Lake

Where is Pattagansett Lake?

Pattagansett 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 Pattagansett Lake?

Pattagansett Lake in New London County, Connecticut has water-quality measurements published by CT DEEP, shown here as reported. Water clarity: 6.8 ft visibility. Surface area: 120 acres.

Measurements on this page ↑

Is Pattagansett Lake safe to swim in?

Nutrient and algae readings are not a swimming clearance. Check local advisories before you swim.

Swimming on this page ↑

Are there boat ramps on Pattagansett Lake?

Pattagansett Lake has 1 documented boat landing in the USGS National Boat Ramps inventory. Named access points include Pattagansett Lake. Public access is listed as yes.

Access on this page ↑

Can I fish at Pattagansett Lake?

Pattagansett Lake has 1 documented boat landing in the USGS National Boat Ramps inventory. Seasons, size and bag limits, and whether you need a license are set by Connecticut's fish and wildlife agency, so check its current regulations before you go.

Access on this page ↑

Where this data comes from

123 measurements from 2 monitoring stations, 2020–2025. Retrieved from the EPA Water Quality Portal on 2026-08-21.

Collected and reported by

  • CT DEEP Volunteer Water Monitoring Program (Volunteer)CTVOLMON64 samples · 2022–2025
  • North American Lake Management SocietyNALMS59 samples · 2020–2024
Monitoring station identifiers (2)

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.

Other records on this page

Named boat-access points from the USGS National Boat Ramps inventory