1
ABlack Hawk Lake
Iowa County, Wisconsin · 11.5 mi from Long Lake
- +Higher grade (B → A)
- ++3.7 ft water clarity
- +Lower phosphorus (19.9 vs 27.9 µg/L)
Cleaner Lakes Than Long Lake
3 higher-graded lakes within 30 miles, ranked by grade improvement and proximity.
Long Lake carries a Grade B (Good) water quality score. Within 30 miles, 3 lakes hold a higher grade. Black Hawk Lake (Iowa County, Grade A, 11.5 mi away) is the closest meaningful upgrade.
2
ACruson Slough Lake
Richland County, Wisconsin · 3.5 mi from Long Lake
- +Higher grade (B → A)
- ++11.6 ft water clarity
3
AGoodwiler Lake
Iowa County, Wisconsin · 12.3 mi from Long Lake
- +Higher grade (B → A)
- ++1.8 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.