A
Marl Lake -
Waukesha County, Wisconsin
Water Quality Grade: A — Excellent
Crystal clear — you can see 45.9 feet down. Phosphorus level: 9.9 µg/L.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 14 m | A |
| Phosphorus | 9.9 µg/L | A |
| Chlorophyll-a (Algae) | No data |
County Ranking
Ranked #9 of 30 lakes in Waukesha County
Data Sources
Data from the EPA Water Quality Portal
Grading methodology based on Metropolitan Council standards
Most recent sample: 2025-06-15
Monitoring stations: 1