Adair County Lake Quality
Iowa, 5 lakes, average grade D (Nutrient-rich)
Adair County holds 5 monitored lakes. With a sample that small the county-level summary describes those specific waters, not necessarily every water body in the county. Every one of those lakes carries an A–F grade, so the county-level summary covers the full set rather than a monitored subset. On average, Adair 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 Mormon Trail Lake (B); the most-stressed is Greenfield Lake (F).
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Quick Answers for Adair County
Planning a trip? Check special fishing regulations for Mormon Trail Lake — or check the official Iowa fishing regulations.
All Lakes in Adair County
5 lakes5 graded lakes
| # | Lake | Grade | Clarity | Phosphorus | Algae | Trophic | Access |
|---|---|---|---|---|---|---|---|
| 1 | BMormon Trail LakeAdair | B | 6.2 ft | 25 µg/L | 9.7 µg/L | No recent samples | Not recorded |
| 2 | DNodaway LakeAdair | D | 2.8 ft | 57 µg/L | 27.6 µg/L | No recent samples | Not recorded |
| 3 | FGreenfield LakeAdair | F | 2.1 ft | 113 µg/L | 53.8 µg/L | No recent samples | Not recorded |
| 4 | FMeadow LakeAdair | F | 1.7 ft | 99 µg/L | 53.1 µg/L | No recent samples | ✓ Public |
| 5 | FLake OrientAdair | F | 1.3 ft | 674 µg/L | 92.2 µg/L | No recent samples | Not recorded |
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Other Counties in Iowa
See how Adair 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.