Hampshire County Lake Quality

Hampshire County's 21 monitored lakes fall in the moderate-density bracket for Massachusetts. The county-level average smooths over real differences — a single agricultural watershed near the southwest corner can pull the average down even if the rest of the county runs clean. 4 of those lakes carry an A–F grade. The county-level summary describes that subset, not every water body listed. The county-wide average lands at B — solid water quality with most lakes carrying clear summer transparency and low-to-moderate phosphorus.

The county's lakes lean shallow, which makes the grades sensitive to wind, sediment-resuspension, and any nutrient inputs from the watershed. The cleanest lake on the books is Arcadia Lake (A); the most-stressed is Nashawannuck Pond (F).