1
ABlack Hawk Lake
Iowa County, Wisconsin · 16 mi from Unknown Lake
- +Two grade letters higher (D → A)
- ++9.3 ft water clarity
- +Lower phosphorus (19.9 vs 135.5 µg/L)
Cleaner Lakes Than Unknown Lake
5 higher-graded lakes within 30 miles, ranked by grade improvement and proximity.
Unknown Lake carries a Grade D (Poor) water quality score. Within 30 miles, 5 lakes hold a higher grade. Black Hawk Lake (Iowa County, Grade A, 16 mi away) is the closest meaningful upgrade.
2
AGoodwiler Lake
Iowa County, Wisconsin · 4.1 mi from Unknown Lake
- +Two grade letters higher (D → A)
- ++7.4 ft water clarity
- +Lower phosphorus (29.7 vs 135.5 µg/L)
3
ACruson Slough Lake
Richland County, Wisconsin · 13.2 mi from Unknown Lake
- +Two grade letters higher (D → A)
- ++17.2 ft water clarity
- +Lower phosphorus (28.9 vs 135.5 µg/L)
4
BJones Slough Lake
Grant County, Wisconsin · 2.4 mi from Unknown Lake
- +Two grade letters higher (D → B)
- ++8.2 ft water clarity
- +Lower phosphorus (31 vs 135.5 µg/L)
5
BKendal Lake
Iowa County, Wisconsin · 5.9 mi from Unknown Lake
- +Two grade letters higher (D → B)
- ++14.7 ft water clarity
- +Lower phosphorus (32.7 vs 135.5 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.