Sunset Lake
Windham County, Vermont95 acresView mapDirections
Clarity, phosphorus, and algae sit in the clean band for this region.
↓ down from A at the last regrade
- Oligotrophic
- Impaired · pH / acidity
- #7 of 9 in the county
- 37 ft max depth
Sunset Lake in Windham County, Vermont has a water quality grade of B (Good). Water clarity: 17.9 ft visibility. Phosphorus: 10.1 µg/L. Chlorophyll-a (algae): 1.8 µg/L. Surface area: 95 acres.
- Clarity
- 17.9 ft
- Max depth
- ~37 ft est.
- Area
- 95 acres
- Type
- Oligotrophic
- Phosphorus
- 10.1 µg/L
- Chlorophyll-a
- 1.8 µg/L
- Trend
- ↑ Improving
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Watch Sunset Lake’s letter
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Sunset Lake is a 95-acre cold, clear oligotrophic lake in Windham County, Vermont with an estimated average depth of about 37 feet. Water quality is graded B based on 1 sampling years through 2024. Overall water quality is improving over recent sampling years. Compared to the 8 other monitored lakes in Windham County, Sunset Lake ranks #7 for water quality.
Source: EPA Water Quality Portal sampling records, VT DEC, last sampled 2024-04-09. Grade methodology: LakeQuality methodology.
What Sunset Lake is good for
From access and monitoring records, not editorial picks.
- Clear water17.9 ft of visibility
Swimming Safety
Grade onlyLow algae
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.
The B is nutrients and algae, not a swimming clearance. Sunset Lake is listed impaired under Clean Water Act §303(d) (IR 4A) for pH / acidity. Check local advisories before you swim.
Water Quality Grade: B (Good)
Crystal clear, you can see 17.9 ft down. Phosphorus 10.1 µg/L. Chlorophyll-a 1.8 µg/L. TSI 36. The letter is not a swimming clearance.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 17.9 ft | Not graded |
| Phosphorus | 10.1 µg/L | Good |
| Chlorophyll-a (Algae) | 1.8 µg/L | Not graded |
| Trophic State Index (TSI) | 36 | Oligotrophic |
Low nutrients, clear water. The letter is not a swimming clearance.
Lake Details
| Characteristic | Value |
|---|---|
| Maximum Depth | ~37 ft est. |
| Average Depth | ~21 ft est. |
| Surface Area | 95 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 Sunset Lake.
Lake Size & Watershed
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.
Fishing Sunset Lake
Water Quality Trend: ↑ Improving
Based on 4 years of monitoring data (2020-2025).
| Metric | Trend | Change/Year | Years |
|---|---|---|---|
| Water Clarity | ↑ Improving | +0.36 m/yr | 4 |
| Phosphorus | ↑ Improving | -0.73 µg/L/yr | 4 |
Reservoir Info (USACE NID)
Sunset Lake is a man-made reservoir impounded by the Sunset Lake (completed 1910), built primarily for water supply on the Stickney Brook; earth-type dam, 14 ft tall and 323 ft long.
- Surface area
- 95 ac
- Normal storage
- 0 ac-ft
- Max storage
- 680 ac-ft
- Drainage area
- 0.85 sq mi
- Hazard class
- Significant
- Owner
- TOWN OF BRATTLEBORO
Source: USACE National Inventory of Dams, NID ID VT00078 · Operator website
EPA Impairment Status
Sunset Lake is officially listed as impaired under Clean Water Act §303(d) in the 2022 EPA reporting cycle (IR category 4A).
Causes of impairment
A Total Maximum Daily Load (TMDL) plan has been approved.
Source: EPA ATTAINS assessment unit VT11-08L01 · Official waterbody report · Matched by proximity (0.05 km)
County Ranking
Ranked #7 of 9 lakes in Windham County
Nearby Lakes With Higher Grades
Sunset Lake holds Grade B. 2 nearby lakes hold higher nutrient-and-algae grades — useful for a swim day, not a reason to skip lodging here.
See full comparison →Nearby Lakes in Windham County
Frequently asked questions about Sunset Lake
Where is Sunset Lake?
- Sunset Lake is a lake in Windham County, Vermont. LakeQuality grades it B for nutrients and algae. The letter is not a swimming clearance.
What is the water quality grade for Sunset Lake?
- Sunset Lake in Windham County, Vermont has a water quality grade of B (Good). Water clarity: 17.9 ft visibility. Phosphorus: 10.1 µg/L. Chlorophyll-a (algae): 1.8 µg/L. Surface area: 95 acres.
Is Sunset Lake safe to swim in?
- The B is nutrients and algae, not a swimming clearance. Sunset Lake is listed impaired under Clean Water Act §303(d) (IR 4A) for pH / acidity. Check local advisories before you swim.
How deep is Sunset Lake?
- No published bathymetric survey covers Sunset Lake, so its depth has not been measured. The HydroLAKES global model estimates an average depth of about 37 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 95 acres.
Explore Sunset Lake across LakeQuality
Species activity outlook by water temperature and season
Where to stay at Vermont's top lakes, each with its grade
Low nutrients, clear water. The letter is not a swimming clearance.
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Where this data comes from
86 measurements from 1 monitoring station, 2020–2024. Retrieved from the EPA Water Quality Portal on 2026-08-02.
Collected and reported by
- Vermont Dept of Environmental Conservation
1VTDECWQ86 samples · 2020–2024
Analytical methods
- 4500 P H ~ Manual Digestion and Flow Injection Analysis for Total Phosphorus
- 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
- 2120 B ~ Color in Water by Visual Comparison
Monitoring station identifiers (1)
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
Lake size & watershed from HydroLAKES (HydroSHEDS)