Seminole County Lake Quality
Oklahoma, 4 lakes, average grade C (Fair)
Only 4 lakes in Seminole 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. 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. Lake Konawa (C) is the cleanest in the county.
Quick Answers for Seminole County
Planning a trip? Check special fishing regulations for Lake Konawa — or check the official Oklahoma fishing regulations.
All Lakes in Seminole County
| Rank | Lake | Grade | Clarity | Phosphorus |
|---|---|---|---|---|
| 1 | Lake Konawa | C | 3.1 ft | 50 µg/L |
| 2 | Sportsman Lake | C | 6.2 ft | 50 µg/L |
| 3 | Wewoka Lake | C | 2.5 ft | 55 µg/L |
| 4 | Nla Lake | D | 3 ft | 24028.2 µg/L |
Other Counties in Oklahoma
See how Seminole 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 Seminole County
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Source: EPA National Aquatic Resource Surveys, 2026.