Grass Lake is a productive, nutrient-rich eutrophic lake in Gladwin County, Michigan. Water quality is graded D based on 1 sampling years through 2022. Overall water quality is improving over recent sampling years. The lake supports 6 documented fish species including Bluntnose minnow, Fathead minnow, and Finescale dace. Public access is available. Compared to the 8 other monitored lakes in Gladwin County, Grass Lake ranks #9 for water quality.
Source: EPA Water Quality Portal sampling records, Michigan DNR, last sampled 2022-09-09. Grade methodology: LakeGrade methodology.
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Swimming Safety
Swimming not recommended, poor water quality with high algae risk
Water Quality Grade: D, Poor
Murky, only visible to about 4 ft. Trophic State Index: 57.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 4 ft | D |
| Phosphorus | No data | |
| Chlorophyll-a (Algae) | No data | |
| Trophic State Index (TSI) | 57 | Eutrophic |
High nutrients, frequent algae, reduced clarity
Where to stay near Grass Lake
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Fish Species
Click a species to see every graded lake where it is documented.
Fishing Grass Lake
Water Quality Trend: ↑ Improving
Based on 3 years of monitoring data (2020-2025).
| Metric | Trend | Change/Year | Years |
|---|---|---|---|
| Water Clarity | ↑ Improving | +0.87 m/yr | 3 |
| Chlorophyll-a | ↑ Improving | -0.8 µg/L/yr | 2 |
Location
County Ranking
Ranked #9 of 9 lakes in Gladwin County
Cleaner Lakes Within 30 Miles
Grass Lake holds Grade D. 4 nearby lakes hold higher grades.
- AIsland Lake Central Basin; Sherman TownshipGladwin County · 0.6 mi · Two grade letters higher (D → A)
- ALancer Lake SoutheastGladwin County · 7.4 mi · Two grade letters higher (D → A)
- BLancelot Lake Southwest BasinGladwin County · 6.1 mi · Two grade letters higher (D → B)
- BGrass LakeGladwin County · 0 mi · Two grade letters higher (D → B)
Nearby Lakes in Gladwin County
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High nutrients, frequent algae, reduced clarity
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More records, surveys & data sources
Data Sources
Water quality data from the EPA Water Quality Portal
Grading methodology based on Metropolitan Council standards
Most recent sample: 2022-09-09
Monitoring stations: 1