How Clean Is Lake Koshkonong?
Lake Koshkonong 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): 5.7 ft. Phosphorus: 287 µg/L. Trophic State Index: 69.
Cleanliness Snapshot
| Metric | Lake Koshkonong | Wisconsin avg |
|---|---|---|
| Overall Grade | D | B |
| Water Clarity (Secchi) | 5.7 ft | — |
| Phosphorus | 287 µg/L | <30 = clean |
| Trophic State Index | 69 | <50 = clean |
How does Lake Koshkonong compare?
Lake Koshkonong's grade of D falls below the Wisconsin state average of B. It ranks #8 of 8 lakes in Jefferson County by water quality score. Multi-year monitoring data shows water quality is stable based on 5 years of records.