Lake Groton
Caledonia County, Vermont414 acresView mapDirections
Vermont DEC publishes the water-quality measurements for Lake Groton. Here is what has been measured.
- Mesotrophic
- 43 ft max depth
Lake Groton in Caledonia County, Vermont has water-quality measurements published by Vermont DEC, shown here as reported. Water clarity: 13.1 ft visibility. Phosphorus: 11.3 µg/L. Chlorophyll-a (algae): 3.3 µg/L. Surface area: 414 acres.
Lake Groton is a 414-acre mesotrophic lake in Caledonia County, Vermont with an estimated average depth of about 43 feet. Overall water quality is improving over recent sampling years. Compared to the 8 other monitored lakes in Caledonia County, Lake Groton ranks #3 for water quality.
Source: EPA Water Quality Portal sampling records, VT DEC, last sampled 2025-08-21. Methodology: how these readings are compared.
Lake Groton covers about 410 acres in Caledonia County. Vrbo is where to look for cabins and lake homes around Lake Groton, and Booking.com and Expedia search hotels near the lake for your dates.
What Lake Groton is good for
From access and monitoring records, not editorial picks.
- Clear water13.1 ft of visibility
Swimming conditions
Readings onlyLow algae
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 Lake Groton is safe to swim in today is a call for the Vermont Department of Environmental Conservation and the county health department, who post current advisories. LakeQuality does not issue swimming clearances.
Water quality measurements for Lake Groton
These are the measurements Vermont DEC publishes for Lake Groton, shown as reported. The condition class beside each reading is the EPA National Lakes Assessment class for this lake’s ecoregion.
Good clarity, visible to about 13.1 ft. Phosphorus 11.3 µg/L. Chlorophyll-a 3.3 µg/L. TSI 40.
| Measure | Reading | Where it sits |
|---|---|---|
| Water clarity (Secchi depth) | 13.1ft | Measured, not scored How deep a black-and-white disk stays visible from the surface. Higher is clearer. |
| Total phosphorus | 11.3µg/L | Good GoodFairPoor |
| Chlorophyll-a (algae) | 3.3µg/L | Good GoodFairPoor |
| Trophic state (TSI)Carlson's 0–100 index of how much algae a lake can support, from clarity, phosphorus and chlorophyll-a. | 40 | Mesotrophic OligotrophicMesotrophicEutrophicHypereutrophic |
Moderate nutrients, good water quality
Ask about Lake Groton
Answers come straight from the public measurements and survey records on this page.
Lake Details
Max depth
~43 ft est.
Surface area
414 acres
Depth marked “est.” is a modeled maximum from GLOBathy (Khazaei et al. 2022, CC0), not a measured survey. Vermont has not published bathymetry for Lake Groton.
Lake Size & Watershed
Watershed (drainage) area
19 sq mi
HydroLAKES / HydroSHEDS
Shoreline
5.7 mi
HydroLAKES / HydroSHEDS
Elevation
1,073 ft
Size, shoreline, and watershed area from HydroLAKES (HydroSHEDS). Mean depth here is modelled, not surveyed — HydroLAKES v1.0 estimates lake depth from surrounding terrain rather than from soundings. Treat it as an approximation, and prefer a state bathymetric survey where one exists.
Stays via Stay22
Stays near Lake Groton
Compare lakeside cabins, hotels, and vacation rentals near Lake Groton in Caledonia County, Vermont — 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 Lake Groton
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Fishing Lake Groton
Water Quality Trend: Improving
Based on 6 years of monitoring (2020–2025).
Water clarity
Worsening6 years
Phosphorus
Improving-0.73 µg/L/yr6 years
Chlorophyll-a
Improving-0.31 µg/L/yr6 years
Reservoir Info (USACE NID)
Lake Groton is a man-made reservoir impounded by the Lake Groton (completed 1968), built primarily for recreation on the Ricker Pond-Tr; concrete-type dam, 13 ft tall and 598 ft long.
- Surface area
- 414 ac
- Normal storage
- 0 ac-ft
- Max storage
- 5,148 ac-ft
- Drainage area
- 18.75 sq mi
- Hazard class
- Low
- Owner
- STATE OF VERMONT - DEC
Source: USACE National Inventory of Dams, NID ID VT00088 · Operator website
Nearby Lakes in Caledonia County
Frequently asked questions about Lake Groton
Where is Lake Groton?
- Lake Groton is a lake in Caledonia County, Vermont. Its water-quality measurements are published by Vermont DEC and shown on this page as reported.
What is the water quality of Lake Groton?
- Lake Groton in Caledonia County, Vermont has water-quality measurements published by Vermont DEC, shown here as reported. Water clarity: 13.1 ft visibility. Phosphorus: 11.3 µg/L. Chlorophyll-a (algae): 3.3 µg/L. Surface area: 414 acres.
Is Lake Groton safe to swim in?
- Nutrient and algae readings are not a swimming clearance. Check local advisories before you swim.
How deep is Lake Groton?
- No published bathymetric survey covers Lake Groton, so its depth has not been measured. The HydroLAKES global model estimates an average depth of about 43 feet, but that is a modelled estimate derived from surrounding terrain rather than a measurement on the water, so treat it as approximate. The lake covers 414 acres.
Explore Lake Groton across LakeQuality
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Where this data comes from
151 measurements from 1 monitoring station, 2020–2025. Retrieved from the EPA Water Quality Portal on 2026-08-02.
Collected and reported by
- Vermont Dept of Environmental Conservation
1VTDECWQ151 samples · 2020–2025
Analytical methods
- EPA approved Alternate Test Procedure for 4500 P H. Has a 28 day hold without acid preservation.
- 445.0 ~ EPA; Chlorophyll and Pheophytin in Algae by Fluorescence
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.
Other records on this page
Lake size & watershed from HydroLAKES (HydroSHEDS)