How Clean Is Madison Lake?
Madison 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): 3.6 ft. Phosphorus: 75 µg/L. Trophic State Index: 63.
Cleanliness Snapshot
| Metric | Madison Lake | Minnesota avg |
|---|---|---|
| Overall Grade | D | C |
| Water Clarity (Secchi) | 3.6 ft | — |
| Phosphorus | 75 µg/L | <30 = clean |
| Trophic State Index | 63 | <50 = clean |
How does Madison Lake compare?
Madison Lake's grade of D falls below the Minnesota state average of C. It ranks #2 of 9 lakes in Blue Earth County by water quality score. Multi-year monitoring data shows water quality is improving based on 4 years of records.