A
St. Johns Lake -
Forest County, Wisconsin
Water Quality Grade: A — Excellent
Crystal clear — you can see 33.5 feet down. Phosphorus level: 14.8 µg/L.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 10.2 m | A |
| Phosphorus | 14.8 µg/L | A |
| Chlorophyll-a (Algae) | No data |
County Ranking
Ranked #22 of 43 lakes in Forest County
Data Sources
Data from the EPA Water Quality Portal
Grading methodology based on Metropolitan Council standards
Most recent sample: 2025-09-22
Monitoring stations: 1