Delaware County Lake Quality
Oklahoma, 2 lakes, average grade D (Poor)
Only 2 lakes in Delaware 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, Delaware County lakes grade D, with phosphorus loading and reduced clarity showing up across most of the dataset.
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 Eucha Lake (C); the most-stressed is Grand Lake (F).
Quick Answers for Delaware County
Planning a trip? Check special fishing regulations for Eucha Lake — or check the official Oklahoma fishing regulations.
All Lakes in Delaware County
| Rank | Lake | Grade | Clarity | Phosphorus |
|---|---|---|---|---|
| 1 | Eucha Lake | C | 3.1 ft | 48 µg/L |
| 2 | Grand Lake | F | 1.6 ft | 760 µg/L |
Other Counties in Oklahoma
See how Delaware 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 Delaware County
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Source: EPA National Aquatic Resource Surveys, 2026.