B

Grass Lake

Gladwin County, WisconsinMesotrophic

Grass Lake is a mesotrophic lake in Gladwin County, MI. Water quality is graded B based on 2 sampling years through 2023. The lake supports 6 documented fish species including Bluntnose minnow, Fathead minnow, and Finescale dace. Compared to the 8 other monitored lakes in Gladwin County, Grass Lake ranks #5 for water quality.

Source: EPA Water Quality Portal sampling records, local state DNR records, last sampled 2023-09-10. Grade methodology: LakeGrade methodology.

Swimming Safety

Good for swimming, clear water with low algae levels

Water Quality Grade: B, Good

Murky, only visible to about 4 ft. Chlorophyll-a: 3.4 µg/L. Trophic State Index: 50.

Metric	Value	Grade
Water Clarity (Secchi Depth)	4 ft	D
Phosphorus	No data
Chlorophyll-a (Algae)	3.4 µg/L	A
Trophic State Index (TSI)	50	Mesotrophic

Moderate nutrients, good water quality

Fish Species

Bluntnose minnow Fathead minnow Finescale dace Green sunfish Smallmouth bass Western banded killifish

Click a species to see all Wisconsin and Minnesota lakes where it is found.

→ Best fishing times for Grass Lake (14-day solunar calendar)

→ Is it safe to eat fish from Grass Lake? (mercury & PFAS guide)

→ Grass Lake fishing regulations (limits, seasons, special rules)

Location

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County Ranking

Ranked #5 of 9 lakes in Gladwin County

Cleaner Lakes Within 30 Miles

Grass Lake holds Grade B. 3 nearby lakes hold higher grades.

See full comparison →

Nearby Lakes in Gladwin County

Island Lake Central Basin; Sherman Township

Lancer Lake Southeast

Lancelot Lake Southwest Basin

Little Lake Twenty

Lake Twenty East Basin

More Wisconsin Lake Rankings

Cleanest lakes in Wisconsin

Top 25 by overall water quality score

Best swimming lakes in Wisconsin

Grade A/B + low algae filter

Family fishing lakes in Wisconsin

Panfish-rich, public access

All Wisconsin lakes

Full state directory

Other Grade B Lakes in Wisconsin

Middle Lake; Elba Township; Section 13

Lapeer County · Clarity: 9.5 ft

Livingston County · Clarity: 13 ft

Bear Lake East Basin; Pleasanton Township

Manistee County · Clarity: 11 ft

Lake County · Clarity: 14 ft

Cass County · Clarity: 10.5 ft

Byram Lake West Central Basin; Fenton Township

Genesee County · Clarity: 10 ft

Mesotrophic Lakes in Wisconsin

Middle Lake; Elba Township; Section 13 Portage Lake Shavehead Lake East Basin; Porter Township Chippewa Lake Northeast Basin; Chippewa Township

Data Sources

Water quality data from the EPA Water Quality Portal

Grading methodology based on Metropolitan Council standards

Most recent sample: 2023-09-10

Monitoring stations: 1