McHenry County Lake Quality

There are 15 monitored lakes in McHenry County. The mix is varied enough that the county-level average tells you the broad strokes, not the choose-this-cabin specifics. 5 of those lakes carry recent nutrient and algae readings. The county-level summary describes that subset, not every water body listed. Most monitored lakes in McHenry County are productive, shallow basins; each lake page shows its own phosphorus and chlorophyll-a readings beside the EPA condition class.

The county's lakes lean shallow, which makes the readings sensitive to wind, sediment-resuspension, and any nutrient inputs from the watershed. The cleanest measured lake is Silver Lake.