San Miguel County Lake Quality
Colorado, 6 lakes — no lake here has enough monitoring data for a grade
San Miguel County holds 6 monitored lakes. With a sample that small the county-level summary describes those specific waters, not necessarily every water body in the county. No lake in San Miguel County has enough sampling behind it for an A–F grade yet. The 6 monitored lakes below carry whatever clarity, phosphorus, and chlorophyll-a measurements exist.
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.
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Quick Answers for San Miguel County
Planning a trip? Check special fishing regulations for Miramonte Reservoir — or check the official Colorado fishing regulations.
All Lakes in San Miguel County
6 lakes · 0 graded, 6 not rated0 graded lakes · 6 not rated, hidden
| # | Lake | Grade | Clarity | Phosphorus | Algae | Trophic | Access |
|---|---|---|---|---|---|---|---|
| NRMiramonte ReservoirSan Miguel | NR | 2.8 ft | 25 µg/L | 7.3 µg/L | No recent samples | ✓ Public | |
| NRTrout LakeSan Miguel | NR | No recent samples | No recent samples | No recent samples | No recent samples | Not recorded | |
| NRLake HopeSan Miguel | NR | No recent samples | No recent samples | No recent samples | No recent samples | Not recorded | |
| NRBlue LakeSan Miguel | NR | No recent samples | No recent samples | No recent samples | No recent samples | Not recorded | |
| NRCone ReservoirSan Miguel | NR | No recent samples | No recent samples | No recent samples | No recent samples | Not recorded | |
| NRGurley ReservoirSan Miguel | NR | No recent samples | No recent samples | No recent samples | No recent samples | Not recorded |
NR = not rated: there is not enough recent sampling to support a letter. That is EPA Integrated Reporting Category 3 (insufficient information), not a failing grade. How grading works.
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Other Counties in Colorado
See how San Miguel County stacks up in the national county water-quality rankings, or browse the full directory of graded lakes across all United States (49 states), Canada (Ontario and Québec), and 38 other country hubs..
Source: EPA National Aquatic Resource Surveys, 2026.