Barnstable County Lake Quality
Massachusetts, 12 lakes, average grade C (Fair)
Barnstable County has 12 graded lakes — a thin enough sample that one or two stressed lakes can move the county average noticeably. Use the per-lake pages below for what actually matters. Barnstable County averages to a C. The distribution behind that average matters more than the letter: a few stressed lakes versus many decent ones can produce the same average as the inverse.
Most of the county's monitored lakes are shallow — under 50 feet — which means wind keeps the water column mixed all summer and sediment-bound phosphorus releases back into the surface layer whenever the bottom is disturbed. Long Pond (A) is the cleanest in the county.
Quick Answers for Barnstable County
Planning a trip? Check special fishing regulations for Long Pond — or check the official Massachusetts fishing regulations.
All Lakes in Barnstable County
| Rank | Lake | Grade | Clarity | Phosphorus |
|---|---|---|---|---|
| 1 | Long Pond | A | - | - |
| 2 | White Pond | A | - | - |
| 3 | Long Pond | B | - | - |
| 4 | Mashpee Pond | B | - | - |
| 5 | Stillwater Pond | B | - | - |
| 6 | Shubael Pond | B | - | - |
| 7 | Hinckleys Pond | C | - | - |
| 8 | Coonamessett Pond | C | - | - |
| 9 | Williams Pond | C | - | - |
| 10 | Jemima Pond | C | - | - |
| 11 | Santuit Pond | F | - | - |
| 12 | Mill Pond | F | - | - |
Other Counties in Massachusetts
See how Barnstable County stacks up in the national county water-quality rankings, or browse the full directory of graded lakes across all 36 states.
Where to stay near Barnstable County
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Source: EPA National Aquatic Resource Surveys, 2026.