Seymour Lake is a mesotrophic lake in Oakland County, Michigan. Water quality is graded C based on 1 sampling years through 2022. Overall water quality is improving over recent sampling years. Compared to the 44 other monitored lakes in Oakland County, Seymour Lake ranks #30 for water quality.
Source: EPA Water Quality Portal sampling records, Michigan DNR, last sampled 2022-09-14. Grade methodology: LakeGrade methodology.
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Swimming Safety
Generally safe for swimming, moderate water quality
Water Quality Grade: C, Fair
Moderate clarity, visible to about 9 ft. Trophic State Index: 45.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 9 ft | C |
| Phosphorus | No data | |
| Chlorophyll-a (Algae) | No data | |
| Trophic State Index (TSI) | 45 | Mesotrophic |
Moderate nutrients, good water quality
Where to stay near Seymour Lake
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Fishing Seymour Lake
Water Quality Trend: ↑ Improving
Based on 4 years of monitoring data (2020-2025).
| Metric | Trend | Change/Year | Years |
|---|---|---|---|
| Water Clarity | ↑ Improving | +1.263 m/yr | 4 |
Location & Depth Map
Free interactive depth-contour map of Seymour Lake, reaching a maximum surveyed depth of 21 ft. Toggle Depth contours to overlay the bathymetric survey lines. Contour data from Michigan DNR.
County Ranking
Ranked #30 of 45 lakes in Oakland County
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Moderate nutrients, good water quality
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Other Grade C Lakes in Michigan
Lapeer County · Clarity: 9 ft
Genesee County · Clarity: 1.8 ft
Lapeer County · Clarity: 7 ft
Lapeer County · Clarity: 7.5 ft
Genesee County · Clarity: 3.8 ft
Livingston County · Clarity: 9.5 ft
Mesotrophic Lakes in Michigan
More records, surveys & data sources
Lake Size & Watershed
Size, shoreline, and watershed area from HydroLAKES (HydroSHEDS). Mean depth is a modeled estimate.
Data Sources
Water quality data from the EPA Water Quality Portal
Lake size & watershed from HydroLAKES (HydroSHEDS)
Grading methodology based on Metropolitan Council standards
Most recent sample: 2022-09-14
Monitoring stations: 1