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Eldred Sherwood Lake carries a Grade F (Algae-prone) water quality score. Within 30 miles, 3 lakes hold a higher grade. Lake Cornelia (Wright County, Grade D, 12.2 mi away) is the closest meaningful upgrade.

Reviewed by LakeQuality Editorial Team · Updated
1
D

Lake Cornelia

Wright County, Iowa · 12.2 mi from Eldred Sherwood Lake
  • +Higher grade (F → D)
  • +Lower phosphorus (37 vs 89 µg/L)
2
D

Clear Lake

Cerro Gordo County, Iowa · 14.5 mi from Eldred Sherwood Lake
  • +Higher grade (F → D)
  • +Lower phosphorus (52 vs 89 µg/L)
3
D

Clear Lake

Cerro Gordo County, Iowa · 14.8 mi from Eldred Sherwood Lake
  • +Higher grade (F → D)
  • +Lower phosphorus (52 vs 89 µg/L)

Reading the cohort

Only 3 lakes within a 30-mile radius score better than Eldred Sherwood Lake's Grade F. The narrow set of options reflects either a fairly clean lake to begin with or a region without a wide range of cleaner alternatives — the trip-planning decision is more constrained than the headline "cleaner lakes nearby" suggests.

Lake Cornelia (Wright County, Grade D) is the closest cleaner option at 12.2 miles from Eldred Sherwood Lake — close enough to be a genuine substitute for most users, far enough that it isn't the same neighborhood lake. Worth the trip if water quality is the primary driver; less obvious if Eldred Sherwood Lake is on the way to other plans.

Lakes are graded A to F on nutrients and algae — total phosphorus, total nitrogen, chlorophyll-a, and turbidity — measured against the EPA National Lakes Assessment 2022 condition classes for that lake's own ecoregion, so a lake is judged against the lakes it would naturally resemble. A higher letter reflects measurably lower nutrient and algae levels, not subjective beauty or access quality — a Grade A lake might have worse boat-launch facilities or shoreline access than a Grade C neighbor, so the ranking is one input alongside the rest of trip planning. The full grading formula is on our methodology page.

How this list is built

Rated lakes on LakeQuality have a letter from EPA Water Quality Portal samples — nutrients and algae measured against EPA National Lakes Assessment ecoregion classes. Secchi is shown, not scored. To suggest cleaner alternatives, we filter lakes within 30 miles to those with a strictly higher numeric score, then rank by grade improvement with a small proximity tiebreak. Cross-state and limited-data lakes are excluded so the list stays locally relevant.