Perry County Lake Quality

Perry County holds 7 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 recent nutrient and algae readings. The county-level summary describes that subset, not every water body listed. The county's readings sit in the middle of the Illinois range, with one or two lakes pulling the average up or down depending on year.

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. Boulder South Lake has the lowest nutrient and algae readings in the county.