Collier-Eagle Lake
- +Two grade letters higher (C → A)
- ++5.5 ft water clarity
3 higher-graded lakes within 30 miles, ranked by grade improvement and proximity.
Collier-Harveys Lake carries a Grade C (Fair) water quality score. Within 30 miles, 3 lakes hold a higher grade. Collier-Eagle Lake (Collier County, Grade A, 7.5 mi away) is the closest meaningful upgrade.
Only 3 lakes within a 30-mile radius score better than Collier-Harveys Lake's Grade C. The narrow set of options reflects either a fairly clean lake to begin with or a region without a wide range of cleaner alternatives — the trip-planning decision is more constrained than the headline "cleaner lakes nearby" suggests.
Collier-Eagle Lake (Collier County, Grade A) is the closest cleaner option at 7.5 miles from Collier-Harveys Lake — 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 Collier-Harveys Lake 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.