Fillmore County Lake Quality

Fillmore County has 1 monitored lake — 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. Every one of those lake carries an A–F grade, so the county-level summary covers the full set rather than a monitored subset. The county average is F — the most-stressed bracket in our rubric. Most monitored lakes here show persistent nutrient loading and algal pressure.

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 Lone Star Reservoir (F); the most-stressed is Lone Star Reservoir (F).