Falls Lake
- +Higher grade (C → B)
- +Lower phosphorus (20 vs 30 µg/L)
1 higher-graded lake within 30 miles, ranked by grade improvement and proximity.
Lake Tillery carries a Grade C (Fair) water quality score. Within 30 miles, 1 lake holds a higher grade. Falls Lake (Montgomery County, Grade B, 7.9 mi away) is the closest meaningful upgrade.
Just one nearby water body scores higher than Lake Tillery on the EPA metrics within a 30-mile radius. The single cleaner option (below) is the practical alternative; beyond that, the next-cleanest lakes sit farther out and warrant a longer drive only if the water-quality difference is the deciding factor.
Falls Lake (Montgomery County, Grade B) is the closest cleaner option at 7.9 miles from Lake Tillery — close enough to be a genuine substitute for most users, far enough that it isn't the same neighborhood lake. Worth the trip if water quality is the primary driver; less obvious if Lake Tillery is on the way to other plans.
The EPA water-quality grading combines clarity (Secchi depth), phosphorus, and chlorophyll-a measurements from state environmental sampling. A higher letter grade reflects measurably cleaner water on those indicators, not subjective beauty or access quality — a Grade A lake might have worse boat-launch facilities or shoreline access than a Grade C neighbor, so the ranking is one input alongside the rest of trip planning. See the methodology page for the full grading formula.
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.