Yuma County Lake Quality
Arizona, 4 lakes, average grade D (Poor)
Yuma County has 4 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. On average, Yuma County lakes grade D, with phosphorus loading and reduced clarity showing up across most of the dataset.
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. Mittry Lake (C) is the cleanest in the county.
Quick Answers for Yuma County
Planning a trip? Check special fishing regulations for Mittry Lake — or check the official Arizona fishing regulations.
All Lakes in Yuma County
| Rank | Lake | Grade | Clarity | Phosphorus |
|---|---|---|---|---|
| 1 | Mittry Lake | C | - | 30 µg/L |
| 2 | Nla Lake | C | 1.5 ft | 39.4 µg/L |
| 3 | Sunris Park Lake | D | - | 98.5 µg/L |
| 4 | Nla Lake | F | 0.1 ft | 392000 µg/L |
Other Counties in Arizona
See how Yuma 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 Yuma County
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Source: EPA National Aquatic Resource Surveys, 2026.