1
CFish Lake
Jackson County, Minnesota · 3.4 mi from Cottonwood Lake
- +Higher grade (D → C)
- +Lower phosphorus (35 vs 86 µg/L)
Cleaner Lakes Than Cottonwood Lake
2 higher-graded lakes within 30 miles, ranked by grade improvement and proximity.
Cottonwood Lake carries a Grade D (Poor) water quality score. Within 30 miles, 2 lakes hold a higher grade. Fish Lake (Jackson County, Grade C, 3.4 mi away) is the closest meaningful upgrade.
2
CHeron Lake
Jackson County, Minnesota · 11.5 mi from Cottonwood Lake
- +Higher grade (D → C)
- +Lower phosphorus (27 vs 86 µg/L)
How this list is built
Every lake on LakeQuality has a calculated grade from EPA Water Quality Portal samples — secchi depth, total phosphorus, and chlorophyll-a measured against Metropolitan Council thresholds. 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.