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LakeQuality

Data Report · Updated July 2026

The State of Vermont’s Lakes 2026

Of 227 monitored lakes in Vermont, 91.6% earn a water-quality grade of A or B and 1.3% score D or F (average grade B). Lake St. Catherine is the cleanest;

227
Monitored lakes graded
B
Average grade
91.6%
Grade A or B
0%
On impaired list

Vermont grade distribution

A
B
C
A: 139 (61.2%)B: 69 (30.4%)C: 16 (7.0%)D: 1 (0.4%)F: 2 (0.9%)

Cleanest lakes in Vermont

Highest combined water-quality score, 2026.

  1. 1.ALake St. Catherine — Rutland County15.4 ft clarity · 13 µg/L P · 3 µg/L chl-a
  2. 2.AValley Lake — Washington County24.4 ft clarity · 17 µg/L P · 3 µg/L chl-a
  3. 3.ABeebe Pond — Rutland County24.6 ft clarity · 10 µg/L P · 1 µg/L chl-a
  4. 4.APeacham Pond — Caledonia County15.6 ft clarity · 11 µg/L P · 2 µg/L chl-a
  5. 5.ABerlin Pond — Washington County21.7 ft clarity · 7 µg/L P · 1 µg/L chl-a
  6. 6.ACaspian Lake — Orleans County29.5 ft clarity · 8 µg/L P · 1 µg/L chl-a
  7. 7.AHarveys Lake — Caledonia County21.0 ft clarity · 8 µg/L P · 1 µg/L chl-a
  8. 8.AMaidstone Lake — Essex County28.5 ft clarity · 7 µg/L P · 1 µg/L chl-a
  9. 9.ANichols Pond — Washington County23.3 ft clarity · 9 µg/L P
  10. 10.ARescue Lake — Windsor County15.1 ft clarity · 11 µg/L P · 2 µg/L chl-a

Most-polluted lakes

Lowest combined water-quality score among monitored lakes.

  1. 1.FShelburne Pond — Chittenden County1.8 ft clarity · 130 µg/L P · 51 µg/L chl-a
  2. 2.FJerome Lake — Addison County98 µg/L P · 41 µg/L chl-a
  3. 3.CWalker Pond — Orleans County51 µg/L P · 21 µg/L chl-a
  4. 4.CMissisquoi Bay Lake — Franklin County5.6 ft clarity · 35 µg/L P · 12 µg/L chl-a
  5. 5.CLake Carmi — Franklin County4.9 ft clarity · 22 µg/L P · 20 µg/L chl-a
  6. 6.CRichville Pond — Addison County1.3 ft clarity · 72 µg/L P · 1 µg/L chl-a
  7. 7.CBig Mud Pond — Rutland County4.3 ft clarity · 24 µg/L P
  8. 8.CGillett Pond — Chittenden County3.1 ft clarity · 26 µg/L P · 7 µg/L chl-a
  9. 9.CSt. Albans Bay Lake — Franklin County6.6 ft clarity · 17 µg/L P · 10 µg/L chl-a
  10. 10.CSouth Bay Lake — Orleans County4.4 ft clarity · 23 µg/L P · 6 µg/L chl-a

Worst algae hotspots

Highest measured chlorophyll-a (algae) concentration.

  1. 1.FShelburne Pond — Chittenden County51 µg/L chlorophyll-a
  2. 2.FJerome Lake — Addison County41 µg/L chlorophyll-a
  3. 3.CWalker Pond — Orleans County21 µg/L chlorophyll-a
  4. 4.CLake Carmi — Franklin County20 µg/L chlorophyll-a

Explore Vermont lakes

Lake Fishing Forecast

Species activity outlook by water temperature and season

Grades combine Secchi clarity, total phosphorus, and chlorophyll-a from the EPA Water Quality Portal and state agencies. See the full methodology, the national State of America’s Lakes report, or all Vermont lakes.

Cite this report: LakeQuality, “The State of Vermont’s Lakes 2026,” lakequality.org/report/vt.