Skip to main content
LakeQuality
Late afternoon sun over Slim Lake, scattering a bright path across wind-textured water
F

Howard County Lake Quality

Iowa, 2 lakes, average grade F (Algae-prone)

Howard County holds 2 monitored lakes. With a sample that small the county-level summary describes those specific waters, not necessarily every water body in the county. 1 of those lake carry an A–F grade. The county-level summary describes that subset, not every water body listed. The county average is F — the most-stressed bracket in our rubric. Most monitored lakes here show persistent nutrient loading and algal pressure.

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 Lake Hendricks (F); the most-stressed is Lake Hendricks (F).

Loading map…

Where to stay near Howard County

Top-rated places to stay near Howard 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 Howard County?

Get lake water-quality report cards plus the best cabin & lodging deals near Howard County — straight to your inbox. No spam, unsubscribe anytime.

All Lakes in Howard County

2 lakes · 1 graded, 1 not rated1 graded lake · 1 not rated, hidden

#LakeGradeClarityPhosphorusAlgaeTrophicAccess
1FLake HendricksHowardF1.5 ft108 µg/L99.1 µg/LNo recent samplesNot recorded
NRLyla MarshHowardNRNo recent samplesNo recent samplesNo recent samplesNo recent samplesNot 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.

Take the quiz →

See how Howard 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.