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LakeQuality

Cleaner Lakes Than Rock Lake

5 higher-graded lakes within 30 miles, ranked by grade improvement and proximity.

Rock Lake carries a Grade B (Good) water quality score. Within 30 miles, 5 lakes hold a higher grade. Ml Lake (Mille Lacs County, Grade A, 7.6 mi away) is the closest meaningful upgrade.

1
A

Ml Lake

Mille Lacs County, Minnesota · 7.6 mi from Rock Lake
  • +Higher grade (B → A)
  • ++12.8 ft water clarity
2
A

Ml-Vineland Lake

Mille Lacs County, Minnesota · 8.8 mi from Rock Lake
  • +Higher grade (B → A)
  • ++18.2 ft water clarity
3
A

Peavy Lake

Morrison County, Minnesota · 3.3 mi from Rock Lake
  • +Higher grade (B → A)
  • ++6.2 ft water clarity
  • +Lower phosphorus (8 vs 18 µg/L)
4
A

Sullivan Lake

Morrison County, Minnesota · 3.7 mi from Rock Lake
  • +Higher grade (B → A)
  • ++3.4 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.

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