Ravalli County Lake Quality
Montana, 1 lakes, average grade A (Excellent)
Only 1 lakes in Ravalli 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. On average, Ravalli County lakes grade an A. That puts it near the top of the {{stateName}} county ranking.
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. Nla Lake (A) is the cleanest in the county.
Quick Answers for Ravalli County
Planning a trip? Check special fishing regulations for Nla Lake — or check the official Montana fishing regulations.
All Lakes in Ravalli County
| Rank | Lake | Grade | Clarity | Phosphorus |
|---|---|---|---|---|
| 1 | Nla Lake | A | 18 ft | 6.9 µg/L |
Other Counties in Montana
See how Ravalli 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 Ravalli County
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Source: EPA National Aquatic Resource Surveys, 2026.