San Miguel County Lake Quality
New Mexico, 6 lakes, average grade B (Good)
Only 6 lakes in San Miguel County carry an active grade. The county-level summary is therefore representative of those specific lakes, not necessarily of every water body in the county. With an average grade of B, San Miguel County sits comfortably above the {{stateName}} median.
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 Conchas Reservoir (A); the most-stressed is Monastery Lake Deep (C).
Quick Answers for San Miguel County
Planning a trip? Check special fishing regulations for Conchas Reservoir — or check the official New Mexico fishing regulations.
All Lakes in San Miguel County
| Rank | Lake | Grade | Clarity | Phosphorus |
|---|---|---|---|---|
| 1 | Conchas Reservoir | A | 8.9 ft | - |
| 2 | Nla Lake | A | 2.3 ft | 21.7 µg/L |
| 3 | Nla Lake | A | 8.2 ft | 17.7 µg/L |
| 4 | Conchas Reservoir Canadian Arm | B | 6.6 ft | - |
| 5 | Monastery Lake Deep | C | 4.1 ft | - |
Other Counties in New Mexico
See how San Miguel County stacks up in the national county water-quality rankings, or browse the full directory of graded lakes across all 34 states.
Where to stay near San Miguel County
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Source: EPA National Aquatic Resource Surveys, 2026.