1
ANorth Twin Lake
Beltrami County, Minnesota · 9.4 mi from Blackduck Lake
- +Two grade letters higher (C → A)
- ++11.2 ft water clarity
- +Lower phosphorus (7 vs 39.5 µg/L)
Cleaner Lakes Than Blackduck Lake
5 higher-graded lakes within 30 miles, ranked by grade improvement and proximity.
Blackduck Lake carries a Grade C (Fair) water quality score. Within 30 miles, 5 lakes hold a higher grade. North Twin Lake (Beltrami County, Grade A, 9.4 mi away) is the closest meaningful upgrade.
2
ASouth Twin Lake
Beltrami County, Minnesota · 10 mi from Blackduck Lake
- +Two grade letters higher (C → A)
- ++10.2 ft water clarity
- +Lower phosphorus (8.5 vs 39.5 µg/L)
3
ALindgren Lake
Beltrami County, Minnesota · 10.9 mi from Blackduck Lake
- +Two grade letters higher (C → A)
- ++7.3 ft water clarity
- +Lower phosphorus (14 vs 39.5 µg/L)
4
BMedicine Lake
Beltrami County, Minnesota · 6.2 mi from Blackduck Lake
- +Higher grade (C → B)
- ++1.7 ft water clarity
- +Lower phosphorus (22 vs 39.5 µg/L)
5
BPimushe Lake
Beltrami County, Minnesota · 11.9 mi from Blackduck Lake
- +Higher grade (C → B)
- ++2 ft water clarity
- +Lower phosphorus (21 vs 39.5 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.