South Bay Lake
Orleans County, VermontView mapDirections
Vermont DEC publishes the water-quality measurements for South Bay Lake. Here is what has been measured.
- Mesotrophic
- 23 ft max depth
- Public access
South Bay Lake in Orleans County, Vermont has water-quality measurements published by Vermont DEC, shown here as reported. Water clarity: 4.4 ft visibility. Phosphorus: 22.7 µg/L. Chlorophyll-a (algae): 6 µg/L.
South Bay Lake is a mesotrophic lake in Orleans County, Vermont with an estimated average depth of about 23 feet. Overall water quality is improving over recent sampling years. Limited fish-species data available. Public access is available with 1 public boat landing. Compared to the 16 other monitored lakes in Orleans County, South Bay Lake ranks #13 for water quality.
Source: EPA Water Quality Portal sampling records, VT DEC, last sampled 2025-10-06. Methodology: how these readings are compared.
What South Bay Lake is good for
From access and monitoring records, not editorial picks.
- Boat launch1 documented ramp
Swimming conditions
Readings onlyModerate 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 South Bay Lake 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 South Bay Lake
These are the measurements Vermont DEC publishes for South Bay Lake, shown as reported. The condition class beside each reading is the EPA National Lakes Assessment class for this lake’s ecoregion.
Murky, only visible to about 4.4 ft. Phosphorus 22.7 µg/L. Chlorophyll-a 6 µg/L. TSI 51.
| Measure | Reading | Where it sits |
|---|---|---|
| Water clarity (Secchi depth) | 4.4ft | Measured, not scored How deep a black-and-white disk stays visible from the surface. Higher is clearer. |
| Total phosphorus | 22.7µg/L | Fair GoodFairPoor |
| Chlorophyll-a (algae) | 6µg/L | Fair GoodFairPoor |
| Trophic state (TSI)Carlson's 0–100 index of how much algae a lake can support, from clarity, phosphorus and chlorophyll-a. | 51 | Mesotrophic OligotrophicMesotrophicEutrophicHypereutrophic |
Moderate nutrients, good water quality
Ask about South Bay Lake
Answers come straight from the public measurements and survey records on this page.
Lake Details
Max depth
~23 ft est.
Public access
Yes
Listed by Vermont DEC
Depth marked “est.” is a modeled maximum from GLOBathy (Khazaei et al. 2022, CC0), not a measured survey. Vermont has not published bathymetry for South Bay Lake.
Lake Size & Watershed
Watershed (drainage) area
460 sq mi
HydroLAKES / HydroSHEDS
Surface area
687 acres
HydroLAKES / HydroSHEDS
Shoreline
8.8 mi
HydroLAKES / HydroSHEDS
Elevation
673 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.
Recreation & Access
- South BayPublic
Named access points in the USGS National Boat Ramps inventory, within about 3 miles. More lakes with boat ramps
Stays via Stay22
Stays near South Bay Lake
Compare lakeside cabins, hotels, and vacation rentals near South Bay Lake in Orleans 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 South Bay Lake
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Fishing South Bay Lake
Water Quality Trend: Improving
Based on 6 years of monitoring (2020–2025).
Water clarity
Improving4 years
Phosphorus
Improving-1.12 µg/L/yr6 years
Chlorophyll-a
Improving-1.68 µg/L/yr6 years
Nearby Lakes in Orleans County
Frequently asked questions about South Bay Lake
Where is South Bay Lake?
- South Bay Lake is a lake in Orleans County, Vermont. Its water-quality measurements are published by Vermont DEC and shown on this page as reported.
What is the water quality of South Bay Lake?
- South Bay Lake in Orleans County, Vermont has water-quality measurements published by Vermont DEC, shown here as reported. Water clarity: 4.4 ft visibility. Phosphorus: 22.7 µg/L. Chlorophyll-a (algae): 6 µg/L.
Is South Bay Lake safe to swim in?
- Nutrient and algae readings are not a swimming clearance. Check local advisories before you swim.
How deep is South Bay Lake?
- No published bathymetric survey covers South Bay Lake, so its depth has not been measured. The HydroLAKES global model estimates an average depth of about 23 feet, but that is a modelled estimate derived from surrounding terrain rather than a measurement on the water, so treat it as approximate.
Are there boat ramps on South Bay Lake?
- South Bay Lake has 1 documented boat landing in the USGS National Boat Ramps inventory. Named access points include South Bay. Public access is listed as yes.
Can I fish at South Bay Lake?
- South Bay 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 Vermont's fish and wildlife agency, so check its current regulations before you go.
Explore South Bay Lake across LakeQuality
More lakes in Vermont
Other Lakes in Vermont
Mesotrophic Lakes in Vermont
Where this data comes from
119 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
1VTDECWQ119 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
- 2130 B ~ Nephelometric Method
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)
Named boat-access points from the USGS National Boat Ramps inventory