Cowley County Lake Quality
Kansas, 5 lakes, average grade D (Poor)
Only 5 lakes in Cowley 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-wide average grade is D — water quality issues are persistent across most of the monitored basins. 0 lakes fall into the F bracket outright.
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 Cowley Co State Fishing Lake (C); the most-stressed is Nla Lake (D).
Quick Answers for Cowley County
Planning a trip? Check special fishing regulations for Cowley Co State Fishing Lake — or check the official Kansas fishing regulations.
All Lakes in Cowley County
| Rank | Lake | Grade | Clarity | Phosphorus |
|---|---|---|---|---|
| 1 | Cowley Co State Fishing Lake | C | 3.9 ft | 26.5 µg/L |
| 2 | Winfield City Lake | C | 3.6 ft | 27.5 µg/L |
| 3 | Nla Lake | C | 2.7 ft | 36 µg/L |
| 4 | Nla Lake | D | 0.6 ft | 557.6 µg/L |
| 5 | Nla Lake | D | 1.1 ft | 103000 µg/L |
Other Counties in Kansas
See how Cowley County stacks up in the national county water-quality rankings, or browse the full directory of graded lakes across all 34 states.
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Source: EPA National Aquatic Resource Surveys, 2026.