Updated Jul 2026
Massachusetts Lake Water Quality
Water quality grades for 98 monitored lakes across 12 counties.
98 {{stateName}} lakes carry a grade. Most of the input data flows through monitoring run by {{agency}}, which feeds state, federal, and volunteer measurements into the EPA Water Quality Portal. Roughly 40% of the state's graded lakes carry an A — 39 lakes that earn the top bracket on the combined Secchi/phosphorus/chlorophyll-a rubric. That share is high by national standards and reflects the depth and natural clarity of glacial lakes in the region.
The state's lakes lean eutrophic: enough nutrient input to support an active algal community, with the trade-offs in clarity and dissolved oxygen that come with it. Norfolk ranks highest on average county grade (A). Middlesex sits lowest. With only 12 counties in the state, the cross-county spread is narrower than the within-county spread for most lakes.
Grade Distribution
How Massachusetts’s 98 graded lakes break down from A (excellent) to F.
Top-Graded Massachusetts Lakes
The highest water-quality grades in Massachusetts — clarity, depth, and A-F grade at a glance.
Sherman Reservoir
Franklin County, Massachusetts
See grade for Sherman Reservoir →Silver Lake
Plymouth County, Massachusetts
See grade for Silver Lake →Long Pond
Barnstable County, Massachusetts
See grade for Long Pond →Gaston Pond
Worcester County, Massachusetts
See grade for Gaston Pond →Bare Hill Pond
Worcester County, Massachusetts
See grade for Bare Hill Pond →Arcadia Lake
Hampshire County, Massachusetts
See grade for Arcadia Lake →Vinica Pond
Hampden County, Massachusetts
See grade for Vinica Pond →Card Pond
Berkshire County, Massachusetts
See grade for Card Pond →Queen Lake
Worcester County, Massachusetts
See grade for Queen Lake →Lake Map
Explore Massachusetts Lakes
Massachusetts reports, fishing & travel
Massachusetts Fishing & Recreation
Licenses, regulations, records, and where to fish across Massachusetts.
Counties
All 12 Massachusetts counties, ranked by average lake water quality. Compare them against every county nationwide in the county rankings, browse the full directory of graded lakes, or pick a different state.
Top 25 Cleanest Lakes
| Rank | Lake | County | Grade | Clarity |
|---|---|---|---|---|
| 1 | Sherman Reservoir | Franklin | A | - |
| 2 | Silver Lake | Plymouth | A | - |
| 3 | Long Pond | Barnstable | A | - |
| 4 | Gaston Pond | Worcester | A | - |
| 5 | Bare Hill Pond | Worcester | A | - |
| 6 | Arcadia Lake | Hampshire | A | - |
| 7 | Vinica Pond | Hampden | A | - |
| 8 | Card Pond | Berkshire | A | - |
| 9 | Queen Lake | Worcester | A | - |
| 10 | Roaring Brook Lake | Franklin | A | - |
| 11 | Benton Pond | Berkshire | A | - |
| 12 | Wrights Reservoir | Worcester | A | - |
| 13 | Ashley Lake | Berkshire | A | - |
| 14 | Quacumquasit Pond | Worcester | A | - |
| 15 | Hamilton Reservoir | Hampden | A | - |
| 16 | Atkins Reservoir | Franklin | A | - |
| 17 | West Branch Walker Brook Lake | Berkshire | A | - |
| 18 | Webster Lake | Worcester | A | - |
| 19 | Hallockville Pond | Franklin | A | - |
| 20 | Damon Pond | Hampshire | A | - |
| 21 | South Reservoir | Middlesex | A | - |
| 22 | Lily Pond | Worcester | A | - |
| 23 | Robbins Pond | Plymouth | A | - |
| 24 | Lake Pearl | Norfolk | A | - |
| 25 | Fall Brook Reservoir | Worcester | A | - |
25 Lakes Needing Attention
| Rank | Lake | County | Grade | Clarity |
|---|---|---|---|---|
| 1 | Wedge Pond | Middlesex | F | - |
| 2 | Spy Pond | Middlesex | F | - |
| 3 | South Watuppa Pond | Bristol | F | - |
| 4 | Cooks Pond | Plymouth | F | - |
| 5 | Mill Pond | Barnstable | F | - |
| 6 | Furnace Pond | Plymouth | F | - |
| 7 | Barkers Pond | Middlesex | F | - |
| 8 | Gleasons Pond | Middlesex | F | - |
| 9 | Little Chauncy Pond | Worcester | F | - |
| 10 | Upper Artichoke Reservoir | Essex | F | - |
| 11 | Bartlett Pond | Worcester | F | - |
| 12 | Nashawannuck Pond | Hampshire | F | - |
| 13 | Billerica Impoundment Lake | Middlesex | F | - |
| 14 | Santuit Pond | Barnstable | F | - |
| 15 | Long Pond-Richardson Beach | Middlesex | F | - |
| 16 | Ten Mile River Lake | Bristol | D | - |
| 17 | Pequot Pond | Hampden | D | - |
| 18 | Horn Pond | Middlesex | C | - |
| 19 | Indian Lake | Worcester | C | - |
| 20 | Jemima Pond | Barnstable | C | - |
| 21 | Halfway Pond | Plymouth | C | - |
| 22 | Williams Pond | Barnstable | C | - |
| 23 | Coonamessett Pond | Barnstable | C | - |
| 24 | Hinckleys Pond | Barnstable | C | - |
| 25 | Cleveland Pond | Plymouth | C | - |
Where to stay near Massachusetts
Top-rated places to stay near Massachusetts
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Source: EPA National Aquatic Resource Surveys, 2026.