1
AGarlk1390a Lake
Mercer County, Wisconsin · 13.9 mi from Harmony Lake
- +Two grade letters higher (C → A)
- ++10.7 ft water clarity
Cleaner Lakes Than Harmony Lake
5 higher-graded lakes within 30 miles, ranked by grade improvement and proximity.
Harmony Lake carries a Grade C (Fair) water quality score. Within 30 miles, 5 lakes hold a higher grade. Garlk1390a Lake (Mercer County, Grade A, 13.9 mi away) is the closest meaningful upgrade.
2
AQacmainstfbk Lake
Mercer County, Wisconsin · 13.9 mi from Harmony Lake
- +Two grade letters higher (C → A)
3
BGarlk1412dw Lake
Mercer County, Wisconsin · 10.7 mi from Harmony Lake
- +Higher grade (C → B)
- ++8.1 ft water clarity
5
BArroda Lake
Oliver County, Wisconsin · 22.5 mi from Harmony Lake
- +Higher grade (C → B)
- ++4.4 ft water clarity
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.