Ingerson Lake is a mesotrophic lake in Allegan County, Michigan. Water quality is graded B based on 3 sampling years through 2025. Overall water quality is declining over recent sampling years. Compared to the 11 other monitored lakes in Allegan County, Ingerson Lake ranks #6 for water quality.
Source: EPA Water Quality Portal sampling records, Michigan DNR, last sampled 2025-11-25. Grade methodology: LakeGrade methodology.
Watch Ingerson Lake water quality
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Swimming Safety
Based on E. coli testing, Ingerson Lake occasionally exceeded the EPA safe-swimming threshold (235 MPN/100mL) — on 8.6% of 35 samples across 8 seasons.
This is a historical summary of past testing, not a current condition — bacteria levels change quickly, especially after rain. Always check Michigan’s current beach and health-department advisories before swimming.
Water Quality Grade: B, Good
Moderate clarity, visible to about 9 ft. Phosphorus level: 41.5 µg/L. Chlorophyll-a: 1.4 µg/L. Trophic State Index: 46.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 9 ft | C |
| Phosphorus | 41.5 µg/L | C |
| Chlorophyll-a (Algae) | 1.4 µg/L | A |
| Trophic State Index (TSI) | 46 | Mesotrophic |
Moderate nutrients, good water quality
Where to stay near Ingerson Lake
Compare lakeside cabins, hotels, and vacation rentals near Ingerson Lake in Allegan County, Michigan — live availability and prices for your trip. Switch the map to Satellite to see the lake and how close each stay is to the water.
Top-rated places to stay near Ingerson Lake
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Fishing Ingerson Lake
Water Quality Trend: ↓ Declining
Based on 6 years of monitoring data (2020-2025).
| Metric | Trend | Change/Year | Years |
|---|---|---|---|
| Water Clarity | ↓ Declining | -0.2 m/yr | 2 |
| Phosphorus | ↓ Declining | +41.9 µg/L/yr | 4 |
Water Temperature
Ingerson Lake averages about 67°F at the surface in summer, usually warmest in Jul (about 68°F) and coldest in Jan (about 39°F). These are typical values by month — not a live reading.
Typical surface water temperature by month, from 679 field readings (2012–2024) via the EPA Water Quality Portal. See the full Ingerson Lake water temperature breakdown →
Location
County Ranking
Ranked #6 of 12 lakes in Allegan County
Cleaner Lakes Within 30 Miles
Ingerson Lake holds Grade B. One nearby lake has a higher grade.
See full comparison →Nearby Lakes in Allegan County
Explore Ingerson Lake across LakeGrade
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Moderate nutrients, good water quality
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More records, surveys & data sources
Regulated Pollution Sources Nearby
1 EPA-permitted facility operate within about 5 miles of Ingerson Lake under Clean Water Act (NPDES) discharge permits.
- John Schaendorf DairyAllegan · 3.9 mi away · NPDES MIG440012
Facilities permitted to discharge under the Clean Water Act within ~5 miles; proximity does not by itself mean a facility affects this lake. Source: EPA ECHO (ICIS-NPDES), as of 2026-07.
Data Sources
Water quality data from the EPA Water Quality Portal
Regulated discharger data from EPA ECHO (ICIS-NPDES)
Grading methodology based on Metropolitan Council standards
Most recent sample: 2025-11-25
Monitoring stations: 1