How Clean Is Alton Lake?
Alton Lake is a clean lake by Minnesota standards. It received a water quality grade of B (Good) based on EPA monitoring data. Water clarity (Secchi depth): 13.5 ft. Trophic State Index: 40.
Cleanliness Snapshot
| Metric | Alton Lake | Minnesota avg |
|---|---|---|
| Overall Grade | B | C |
| Water Clarity (Secchi) | 13.5 ft | — |
| Trophic State Index | 40 | <50 = clean |
How does Alton Lake compare?
Alton Lake's grade of B matches or beats the Minnesota state average of C. It ranks #57 of 128 lakes in Cook County by water quality score. Multi-year monitoring data shows water quality is declining based on 2 years of records.