1
AOasis Ranch Lake
Audrain County, Wisconsin · 17 mi from Mark Twain Lake
- +Two grade letters higher (F → A)
- ++11.6 ft water clarity
- +Lower phosphorus (8 vs 80 µg/L)
Cleaner Lakes Than Mark Twain Lake
5 higher-graded lakes within 30 miles, ranked by grade improvement and proximity.
Mark Twain Lake carries a Grade F (Very Poor) water quality score. Within 30 miles, 5 lakes hold a higher grade. Oasis Ranch Lake (Audrain County, Grade A, 17 mi away) is the closest meaningful upgrade.
2
AOasis Ranch Upper Lake
Audrain County, Wisconsin · 17.1 mi from Mark Twain Lake
- +Two grade letters higher (F → A)
- ++11.9 ft water clarity
- +Lower phosphorus (12 vs 80 µg/L)
3
CMark Twain Lake
Monroe County, Wisconsin · 4.8 mi from Mark Twain Lake
- +Two grade letters higher (F → C)
- ++1.3 ft water clarity
- +Lower phosphorus (36 vs 80 µg/L)
4
CMark Twain Lake Indian Creek Arm
Ralls County, Wisconsin · 9.1 mi from Mark Twain Lake
- +Two grade letters higher (F → C)
- ++1.3 ft water clarity
- +Lower phosphorus (31.5 vs 80 µg/L)
5
CMark Twain Lake by Hwy J
Ralls County, Wisconsin · 10.5 mi from Mark Twain Lake
- +Two grade letters higher (F → C)
- ++1.2 ft water clarity
- +Lower phosphorus (33.6 vs 80 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.