Navajo County Lake Quality
Arizona, 5 lakes, average grade C (Fair)
Navajo County has 5 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.
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 Fool Hollow Lake (C); the most-stressed is Rainbow Lake (D).
Quick Answers for Navajo County
Planning a trip? Check special fishing regulations for Fool Hollow Lake — or check the official Arizona fishing regulations.
All Lakes in Navajo County
| Rank | Lake | Grade | Clarity | Phosphorus |
|---|---|---|---|---|
| 1 | Fool Hollow Lake | C | 4.3 ft | 32 µg/L |
| 2 | Show Low Lake | C | 8.4 ft | 30.5 µg/L |
| 3 | Nla Lake | C | 1 ft | 79000 µg/L |
| 4 | Rainbow Lake | D | 1.1 ft | 64 µg/L |
| 5 | Black Canyon Lake | D | 6.1 ft | 83 µg/L |
Other Counties in Arizona
See how Navajo 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 Navajo County
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Source: EPA National Aquatic Resource Surveys, 2026.