How Clean Is Lake Poygan?
Lake Poygan does not have enough monitoring data to grade. Its EPA monitoring record does not meet the evidence bar for a letter grade, so it is published unrated — that is an absence of evidence, not a poor result. The measurements below are what the record does contain. Water clarity (Secchi depth): 2.5 ft. Trophic State Index: 64.
Cleanliness Snapshot
| Metric | Lake Poygan | Wisconsin avg |
|---|---|---|
| Overall Grade | NR | B |
| Water Clarity (Secchi) | 2.5 ft | — |
| Trophic State Index | 64 | <50 = clean |
How does Lake Poygan compare?
Lake Poygan is not rated for water quality — its monitoring record does not meet the evidence bar, so it is not compared with the Wisconsin state average. Multi-year monitoring data shows water quality is stable based on 6 years of records.