1
BArrowhead Lake
Sac County, Iowa · 20.9 mi from Swan Lake Max Depth
- +Two grade letters higher (F → B)
- ++4.2 ft water clarity
- +Lower phosphorus (26 vs 433 µg/L)
Cleaner Lakes Than Swan Lake Max Depth
3 higher-graded lakes within 30 miles, ranked by grade improvement and proximity.
Swan Lake Max Depth carries a Grade F (Algae-prone) water quality score. Within 30 miles, 3 lakes hold a higher grade. Arrowhead Lake (Sac County, Grade B, 20.9 mi away) is the closest meaningful upgrade.
Reviewed by LakeQuality Editorial Team · Updated
2
DYellow Smoke Lake
Crawford County, Iowa · 24.9 mi from Swan Lake Max Depth
- +Higher grade (F → D)
- ++1.6 ft water clarity
- +Lower phosphorus (56.5 vs 433 µg/L)
3
DSpringbrook Lake
Guthrie County, Iowa · 26.4 mi from Swan Lake Max Depth
- +Higher grade (F → D)
- ++1.6 ft water clarity
- +Lower phosphorus (59 vs 433 µg/L)
Reading the cohort
Only 3 lakes within a 30-mile radius score better than Swan Lake Max Depth'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.
The nearest cleaner alternative — Arrowhead Lake in Sac County — sits 20.9 miles from Swan Lake Max Depth, putting it firmly in "destination trip" rather than "neighborhood swap" range. The water-quality gap has to be the deciding factor; for a casual outing, Swan Lake Max Depth is the practical choice and the cleaner options are reserved for purpose-specific visits.
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.