How Clean Is Jefferson Lake?
Jefferson Lake has poor water quality, with elevated phosphorus and algae. It received a water quality grade of D (Poor) based on EPA monitoring data. Water clarity (Secchi depth): 2 ft. Phosphorus: 86.5 µg/L. Trophic State Index: 68.
Cleanliness Snapshot
| Metric | Jefferson Lake | Minnesota avg |
|---|---|---|
| Overall Grade | D | C |
| Water Clarity (Secchi) | 2 ft | — |
| Phosphorus | 86.5 µg/L | <30 = clean |
| Trophic State Index | 68 | <50 = clean |
How does Jefferson Lake compare?
Jefferson Lake's grade of D falls below the Minnesota state average of C. It ranks #10 of 16 lakes in Le Sueur County by water quality score. Multi-year monitoring data shows water quality is declining based on 6 years of records.