1
ABlack Hawk Lake
Iowa County, Wisconsin · 25.6 mi from Hidden Valley Lake
- +Higher grade (B → A)
- +Lower phosphorus (19.9 vs 44.7 µg/L)
Cleaner Lakes Than Hidden Valley Lake
1 higher-graded lake within 30 miles, ranked by grade improvement and proximity.
Hidden Valley Lake carries a Grade B (Good) water quality score. Within 30 miles, 1 lake holds a higher grade. Black Hawk Lake (Iowa County, Grade A, 25.6 mi away) is the closest meaningful upgrade.
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.