Grass Lake
Gladwin County, Michigan24 acresView mapDirections
Not Rated: one monitoring station are on record, but they measured water clarity only. LakeQuality’s A–F method grades total phosphorus, total nitrogen, chlorophyll-a, and turbidity; clarity is shown, not scored.
- 8 ft max depth
- Limited data
Grass Lake in Gladwin County, Michigan is not rated for water quality — its monitoring record does not meet the evidence bar. Water clarity: 4 ft visibility. Maximum depth: 8 ft. Surface area: 24.1 acres.
- Clarity
- 4 ft
- Max depth
- 8 ft
- Area
- 24 acres
- Trend
- ↑ Improving
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Stays near Grass Lake
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Watch Grass Lake’s letter
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Why Grass Lake has no grade
Grass Lake has monitoring on record from one station, but only water clarity was measured. LakeQuality’s A–F letter uses total phosphorus, total nitrogen, chlorophyll-a, and turbidity against EPA National Lakes Assessment condition classes. With none of those grading measurements on record, Grass Lake is Not Rated — not an F. Its 4-foot median from 18 readings collected 2021–2022 is still shown as clarity, but clarity alone cannot earn a letter.
Not Rated is EPA Integrated Reporting Category 3 — insufficient information. Everything below that has been measured is still reported on this page.
Sampling is run by EGLE and volunteer programs, and published through the EPA Water Quality Portal. Read the full grading methodology.
Grass Lake is a 24-acre lake in Gladwin County, Michigan with a maximum depth of 8 feet. Overall water quality is improving over recent sampling years. The lake supports 6 documented fish species including Bluntnose minnow, Fathead minnow, and Finescale dace.
Source: EPA Water Quality Portal sampling records, EGLE, last sampled 2022-09-09. Grade methodology: LakeQuality methodology.
What Grass Lake is good for
From access and monitoring records, not editorial picks.
- Fishing6 species recorded
Swimming Safety
Not ratedLimited data
The letter is not a swimming clearance. Check local advisories before you swim.
Water quality measurements for Grass Lake
These readings exist but are not enough for an A–F grade — see why.
Murky, only visible to about 4 ft. TSI 57.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 4 ft | Not graded |
| Phosphorus | No recent samples | |
| Chlorophyll-a (Algae) | No recent samples | |
| Trophic State Index (TSI) | 57 | Eutrophic |
High nutrients, frequent algae, reduced clarity
Lake Details
| Characteristic | Value |
|---|---|
| Maximum Depth | 8 ft |
| Surface Area | 24 acres |
Fish Species
Click a species to see every graded lake where it is documented.
Fishing Grass Lake
Water Quality Trend: ↑ Improving
Based on 4 years of monitoring data (2020-2025).
| Metric | Trend | Change/Year | Years |
|---|---|---|---|
| Water Clarity | ↑ Improving | +0.87 m/yr | 3 |
| Phosphorus | ↓ Declining | +2.6 µg/L/yr | 4 |
| Chlorophyll-a | ↑ Improving | -0.2 µg/L/yr | 2 |
Graded lakes near Grass Lake
Grass Lake has no grade, but these lakes within a short drive do.
Nearby Lakes in Gladwin County
Frequently asked questions about Grass Lake
Where is Grass Lake?
- Grass Lake is a lake in Gladwin County, Michigan. LakeQuality has not rated this lake (UNRATED) — the only measurement available is water clarity, which is not a water-quality indicator on its own — EPA's National Lakes Assessment does not grade clarity.
What is the water quality grade for Grass Lake?
- Grass Lake in Gladwin County, Michigan is not rated for water quality — its monitoring record does not meet the evidence bar. Water clarity: 4 ft visibility. Maximum depth: 8 ft. Surface area: 24.1 acres.
Is Grass Lake safe to swim in?
- The letter is not a swimming clearance. Check local advisories before you swim.
How deep is Grass Lake?
- Grass Lake has a maximum depth of 8 feet. The lake covers 24.1 acres.
What fish are in Grass Lake?
- Fish species found in Grass Lake include Bluntnose minnow, Fathead minnow, Finescale dace, Green sunfish, Smallmouth bass, Western banded killifish. Grass Lake is located in Gladwin County, Michigan.
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Where this data comes from
18 measurements from 1 monitoring station, 2021–2022. Retrieved from the EPA Water Quality Portal on 2026-08-26.
Collected and reported by
- North American Lake Management Society
NALMS18 samples · 2021–2022
Monitoring station identifiers (1)
Grade thresholds from the EPA National Lakes Assessment (EPA 841-R-24-006, Table 6-3), applied by ecoregion. See how grades are calculated and data sources.