Osage County Lake Quality
Kansas, 6 lakes, average grade C (Fair)
Osage County holds 6 monitored lakes. With a sample that small the county-level summary describes those specific waters, not necessarily every water body in the county. 4 of those lakes carry an A–F grade. The county-level summary describes that subset, not every water body listed. 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 Osage Co State Fishing Lake (A); the most-stressed is Pomona Lake (F).
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Quick Answers for Osage County
Planning a trip? Check special fishing regulations for Osage Co State Fishing Lake — or check the official Kansas fishing regulations.
All Lakes in Osage County
6 lakes · 4 graded, 2 not rated4 graded lakes · 2 not rated, hidden
| # | Lake | Grade | Clarity | Phosphorus | Algae | Trophic | Access |
|---|---|---|---|---|---|---|---|
| 1 | AOsage Co State Fishing LakeOsage | A | 6.2 ft | 20 µg/L | 6 µg/L | No recent samples | ✓ Public |
| 2 | AMelvern LakeOsage | A | 4.8 ft | 20 µg/L | 6 µg/L | No recent samples | ✓ Public |
| 3 | DStrowbridge ReservoirOsage | D | 2.4 ft | 48.5 µg/L | 27 µg/L | No recent samples | Not recorded |
| 4 | FPomona LakeOsage | F | 2.9 ft | 67 µg/L | 31.5 µg/L | No recent samples | ✓ Public |
| NRCarbondale West LakeOsage | NR | 0.6 ft | No recent samples | No recent samples | No recent samples | Not recorded | |
| NROsage City ReservoirOsage | NR | No recent samples | No recent samples | No recent samples | No recent samples | Not recorded |
NR = not rated: there is not enough recent sampling to support a letter. That is EPA Integrated Reporting Category 3 (insufficient information), not a failing grade. How grading works.
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Other Counties in Kansas
See how Osage County stacks up in the national county water-quality rankings, or browse the full directory of graded lakes across all United States (49 states), Canada (Ontario, Québec, Nova Scotia, British Columbia and Newfoundland and Labrador), and 38 other country hubs..
Source: EPA National Aquatic Resource Surveys, 2026.