1
BPoplar Lake
Polk County, Minnesota · 5.1 mi from Turtle Lake
- +Higher grade (C → B)
- ++5.3 ft water clarity
- +Lower phosphorus (23 vs 56.5 µg/L)
Cleaner Lakes Than Turtle Lake
2 higher-graded lakes within 30 miles, ranked by grade improvement and proximity.
Turtle Lake carries a Grade C (Fair) water quality score. Within 30 miles, 2 lakes hold a higher grade. Poplar Lake (Polk County, Grade B, 5.1 mi away) is the closest meaningful upgrade.
2
CSpring Lake
Polk County, Minnesota · 7.7 mi from Turtle Lake
- +Higher overall water quality score
- ++1.3 ft water clarity
- +Lower phosphorus (27.5 vs 56.5 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.