A
Birch Lake -
Walworth County, Wisconsin
Water Quality Grade: A — Excellent
Crystal clear — you can see 18.0 feet down. Phosphorus level: 27.6 µg/L.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 5.5 m | A |
| Phosphorus | 27.6 µg/L | B |
| Chlorophyll-a (Algae) | No data |
County Ranking
Ranked #55 of 69 lakes in Walworth 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