Williamson County Lake Quality

Williamson County has 13 monitored 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. 1 of those lake carry an A–F grade. The county-level summary describes that subset, not every water body listed. On average, Williamson County lakes grade D, with phosphorus loading and reduced clarity showing up across most of the dataset.

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. Lake of Egypt (D) is the cleanest in the county.