A
Norris Lake
Mahnomen County, Minnesota
Water Quality Grade: A — Excellent
Good clarity — visible to about 11.6 feet. Phosphorus level: 15 µg/L.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 3.55 m | B |
| Phosphorus | 15 µg/L | A |
| Chlorophyll-a (Algae) | No data |
County Ranking
Ranked #4 of 17 lakes in Mahnomen County
Data Sources
Data from the EPA Water Quality Portal
Grading methodology based on Metropolitan Council standards
Most recent sample: 2025-09-09
Monitoring stations: 2