Clarke County Lake Quality
Iowa, 3 lakes, average grade D (Nutrient-rich)
Clarke County has 3 monitored lakes — a thin enough sample that one or two stressed lakes can move the county average noticeably. Use the per-lake pages below for what actually matters. 2 of those lakes carry an A–F grade. The county-level summary describes that subset, not every water body listed. On average, Clarke 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 West Lake Osceola (D); the most-stressed is East Lake Osceola (F).
Where to stay near Clarke County
Top-rated places to stay near Clarke County
Prices for Sep 11–13, 4 adults. Change dates on the map below.
Availability and prices from Stay22 partners (Booking.com, Vrbo, Expedia). We may earn a commission from bookings, at no extra cost to you.
Planning a trip to Clarke County?
Get lake water-quality report cards plus the best cabin & lodging deals near Clarke County — straight to your inbox. No spam, unsubscribe anytime.
Quick Answers for Clarke County
Planning a trip? Check special fishing regulations for West Lake Osceola — or check the official Iowa fishing regulations.
All Lakes in Clarke County
3 lakes · 2 graded, 1 not rated2 graded lakes · 1 not rated, hidden
| # | Lake | Grade | Clarity | Phosphorus | Algae | Trophic | Access |
|---|---|---|---|---|---|---|---|
| 1 | DWest Lake OsceolaClarke | D | 2.2 ft | 75.5 µg/L | 28.7 µg/L | No recent samples | Not recorded |
| 2 | FEast Lake OsceolaClarke | F | 1.2 ft | 268.3 µg/L | 81.6 µg/L | No recent samples | Not recorded |
| NRGrade LakeClarke | 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.
Lake Match
Which lake suits how you actually use one?
Six questions — swimming, fishing, quiet, cabins, drive time — and a shortlist of graded lakes that fit, with the water quality behind each one.
Other Counties in Iowa
See how Clarke 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.