1
BSchool Lake
Chisago County, Minnesota · 2.3 mi from Green Lake
- +Higher grade (C → B)
- ++1.9 ft water clarity
- +Lower phosphorus (20 vs 26 µg/L)
Cleaner Lakes Than Green Lake
4 higher-graded lakes within 30 miles, ranked by grade improvement and proximity.
Green Lake carries a Grade C (Fair) water quality score. Within 30 miles, 4 lakes hold a higher grade. School Lake (Chisago County, Grade B, 2.3 mi away) is the closest meaningful upgrade.
2
BMattson Lake
Chisago County, Minnesota · 2.8 mi from Green Lake
- +Higher grade (C → B)
- +Lower phosphorus (16 vs 26 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.