Is Jefferson Lake Safe for Swimming?
Jefferson Lake in Le Sueur County, Minnesota has a water quality grade of F (Algae-prone). Algae and nutrients are often high — check current advisories before swimming. Skip the water if you see scum or a paint-like bloom. Water clarity: 2 ft visibility. Phosphorus: 86.5 µg/L. Chlorophyll-a (algae): 72 µg/L. Always check local health department advisories before swimming.
Key Metrics
| Metric | Value |
|---|---|
| Overall Grade | F (Algae-prone) |
| Water Clarity (Secchi Depth) | 2 ft |
| Phosphorus | 86.5 μg/L |
| Chlorophyll-a (Algae) | 72 μg/L |
| Location | Le Sueur County, Minnesota |
How does Jefferson Lake compare?
With an overall water quality grade of F, Jefferson Lake falls below the Minnesota state average of Grade C. It ranks #10 of 13 lakes in Le Sueur County by water quality score.
Water clarity (Secchi depth) sits at 2 feet. That signals heavy algae or sediment, often tied to high phosphorus from runoff. Algae levels (chlorophyll-a) measure 72 µg/L — elevated; risk of harmful algal bloom advisories increases at this concentration.
Watch Jefferson Lake water quality
Get an email when the grade, clarity, or algae reading changes. Unsubscribe anytime.