Grass Lake
St. Joseph County, Michigan28 acresView mapDirections
EGLE publishes the water-quality measurements for Grass Lake. Here is what has been measured.
- Limited data
Grass Lake in St. Joseph County, Michigan has water-quality measurements published by EGLE, shown here as reported. Water clarity: 7 ft visibility. Phosphorus: 18 µg/L. Surface area: 28.2 acres.
Grass Lake is a 28-acre lake in St. Joseph County, Michigan. 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 2018-09-20. Methodology: how these readings are compared.
What Grass Lake is good for
From access and monitoring records, not editorial picks.
- Fishing6 species recorded
Swimming conditions
No readingLimited data
Nutrient and algae readings are not a swimming clearance. Check local advisories before you swim.
Whether Grass Lake is safe to swim in today is a call for the Michigan Department of Environment, Great Lakes, and Energy (EGLE) and the county health department, who post current advisories. LakeQuality does not issue swimming clearances.
Water quality measurements for Grass Lake
These are the measurements EGLE publishes for Grass Lake, shown as reported. The condition class beside each reading is the EPA National Lakes Assessment class for this lake’s ecoregion.
Moderate clarity, visible to about 7 ft. Phosphorus 18 µg/L. TSI 47.
| Measure | Reading | Where it sits |
|---|---|---|
| Water clarity (Secchi depth) | 7ft | Measured, not scored How deep a black-and-white disk stays visible from the surface. Higher is clearer. |
| Total phosphorus | 18µg/L | Measured, not scored The nutrient that most limits algae growth in freshwater. More phosphorus, more algae potential. |
| Chlorophyll-a (algae) | No reading The green pigment in algae — a direct measure of how much algae is in the water. | |
| Trophic state (TSI)Carlson's 0–100 index of how much algae a lake can support, from clarity, phosphorus and chlorophyll-a. | 47 | Mesotrophic OligotrophicMesotrophicEutrophicHypereutrophic |
Moderate nutrients, good water quality
Ask about Grass Lake
Answers come straight from the public measurements and survey records on this page.
Lake Details
Surface area
28 acres
No bathymetric survey has been published for Grass Lake, so its depth is not documented here.
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Fish Species
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Fishing Grass Lake
Nearby Lakes in St. Joseph County
Frequently asked questions about Grass Lake
Where is Grass Lake?
- Grass Lake is a lake in St. Joseph County, Michigan. Its water-quality measurements are published by EGLE and shown on this page as reported.
What is the water quality of Grass Lake?
- Grass Lake in St. Joseph County, Michigan has water-quality measurements published by EGLE, shown here as reported. Water clarity: 7 ft visibility. Phosphorus: 18 µg/L. Surface area: 28.2 acres.
Is Grass Lake safe to swim in?
- Nutrient and algae readings are not a swimming clearance. Check local advisories before you swim.
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 St. Joseph County, Michigan.
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Where this data comes from
15 measurements from 1 monitoring station, 2018. Retrieved from the EPA Water Quality Portal on 2026-08-26.
Collected and reported by
- Michigan EGLE - MiCorps
21MICH_MICORPS15 samples · 2018
Analytical methods
- Phosphorus by Colorimetry
Monitoring station identifiers (1)
EPA condition classes from the National Lakes Assessment (EPA 841-R-24-006, Table 6-3), applied by ecoregion. See where the data comes from and data sources.