D
Long Lake -
Manitowoc County, Wisconsin
Water Quality Grade: D — Poor
Murky — only visible to about 5.2 feet. Phosphorus level: 90.4 µg/L.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 1.6 m | D |
| Phosphorus | 90.4 µg/L | F |
| Chlorophyll-a (Algae) | No data |
County Ranking
Ranked #28 of 28 lakes in Manitowoc County
Data Sources
Data from the EPA Water Quality Portal
Grading methodology based on Metropolitan Council standards
Most recent sample: 2025-08-25
Monitoring stations: 1