Lake County Lake Quality
Colorado, 3 lakes, average grade B (Good)
Lake County has 3 graded 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. With an average grade of B, Lake County sits comfortably above the {{stateName}} median.
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. Turquoise Reservoir (A) is the cleanest in the county.
Quick Answers for Lake County
Planning a trip? Check special fishing regulations for Turquoise Reservoir — or check the official Colorado fishing regulations.
All Lakes in Lake County
| Rank | Lake | Grade | Clarity | Phosphorus |
|---|---|---|---|---|
| 1 | Turquoise Reservoir | A | 16.1 ft | - |
| 2 | Twin Lakes East | B | 14.1 ft | - |
| 3 | Twin Lakes West | B | 11.5 ft | - |
Other Counties in Colorado
See how Lake County stacks up in the national county water-quality rankings, or browse the full directory of graded lakes across all 12 states.
Where to stay near Lake County
Top-rated places to stay near Lake County
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Source: EPA National Aquatic Resource Surveys, 2026.