Power County Lake Quality
Idaho, 6 lakes, average grade C (Fair)
Power 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. American Falls Reservoir (C) is the cleanest in the county.
Quick Answers for Power County
Planning a trip? Check special fishing regulations for American Falls Reservoir — or check the official Idaho fishing regulations.
All Lakes in Power County
| Rank | Lake | Grade | Clarity | Phosphorus |
|---|---|---|---|---|
| 1 | American Falls Reservoir | C | - | 32 µg/L |
| 2 | American Falls R-Sr Cattle Tower Lake | C | - | 38.5 µg/L |
| 3 | American Falls Res Off Seagull Bay Lake | C | - | 47 µg/L |
| 4 | American Falls R-Sportsmans Cove Lake | C | - | 55 µg/L |
| 5 | American Falls R-Little Hole Draw Lake | C | - | 61 µg/L |
Other Counties in Idaho
See how Power 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 Power County
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Source: EPA National Aquatic Resource Surveys, 2026.