Montrose County Lake Quality

Montrose County has 6 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, Montrose County lakes grade an A. That puts it near the top of the Colorado 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. Crystal Reservoir (A) is the cleanest in the county.