Owyhee County Lake Quality
Idaho, 7 lakes, average grade D (Poor)
Only 7 lakes in Owyhee 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. The county-wide average grade is D — water quality issues are persistent across most of the monitored basins. 2 lakes fall into the F bracket outright.
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 Nla Lake (B); the most-stressed is Nla Lake (F).
Quick Answers for Owyhee County
Planning a trip? Check special fishing regulations for Nla Lake — or check the official Idaho fishing regulations.
All Lakes in Owyhee County
| Rank | Lake | Grade | Clarity | Phosphorus |
|---|---|---|---|---|
| 1 | Nla Lake | B | 10.8 ft | 41.6 µg/L |
| 2 | Mountain View Lake | C | - | 39 µg/L |
| 3 | Nla Lake | D | 3 ft | 147.3 µg/L |
| 4 | Nla Lake | D | 5.2 ft | 68000 µg/L |
| 5 | Nla Lake | D | 0.7 ft | 201000 µg/L |
| 6 | Nla Lake | F | 0.7 ft | 275000 µg/L |
| 7 | Mpipeline Rd Lake | F | - | 6820 µg/L |
Other Counties in Idaho
See how Owyhee 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 Owyhee County
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Source: EPA National Aquatic Resource Surveys, 2026.