Nez Perce County Lake Quality
Idaho, 6 lakes, average grade C (Fair)
Nez Perce County has 6 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. The county average is C — the middle of the rubric, with one or two lakes pulling the average up or down depending on year.
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. Waha Reservoir Middle (B) is the cleanest in the county.
Quick Answers for Nez Perce County
Planning a trip? Check special fishing regulations for Waha Reservoir Middle — or check the official Idaho fishing regulations.
All Lakes in Nez Perce County
| Rank | Lake | Grade | Clarity | Phosphorus |
|---|---|---|---|---|
| 1 | Waha Reservoir Middle | B | 9.7 ft | 45 µg/L |
| 2 | Waha Reservoir | C | 9.7 ft | 61 µg/L |
| 3 | Nla Lake | C | 7.5 ft | 77000 µg/L |
Other Counties in Idaho
See how Nez Perce 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 Nez Perce County
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Source: EPA National Aquatic Resource Surveys, 2026.