How Clean Is Johnson Lake?
Johnson Lake has very poor water quality and a high algae bloom risk. It received a water quality grade of F (Very Poor) based on EPA monitoring data. Water clarity (Secchi depth): 3 ft. Trophic State Index: 61.
Cleanliness Snapshot
| Metric | Johnson Lake | Minnesota avg |
|---|---|---|
| Overall Grade | F | C |
| Water Clarity (Secchi) | 3 ft | — |
| Trophic State Index | 61 | <50 = clean |
How does Johnson Lake compare?
Johnson Lake's grade of F falls below the Minnesota state average of C. It ranks #184 of 187 lakes in St. Louis County by water quality score. Multi-year monitoring data shows water quality is declining based on 2 years of records.