Isabella County Lake Quality

Isabella County holds 12 monitored lakes. With a sample that small the county-level summary describes those specific waters, not necessarily every water body in the county. 2 of those lakes carry an A–F grade. The county-level summary describes that subset, not every water body listed. On average, Isabella County lakes grade an A. That puts it near the top of the Michigan county ranking.

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. Coldwater Lake (A) is the cleanest in the county.