D

Grass Lake

Gladwin County, WisconsinLimited DataEutrophic

Grass Lake is a productive, nutrient-rich eutrophic lake in Gladwin County, MI. Water quality is graded D based on 1 sampling years through 2022. 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 #9 for water quality.

Source: EPA Water Quality Portal sampling records, local state DNR records, last sampled 2022-09-09. Grade methodology: LakeGrade methodology.

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

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 #9 of 9 lakes in Gladwin County

Cleaner Lakes Within 30 Miles

Grass Lake holds Grade D. 4 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

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 D Lakes in Wisconsin

Newaygo County · Clarity: 4.5 ft

Community College Pond

Chippewa County · Clarity: 1.5 ft

Little Beaver Lake

Alger County · Clarity: 6.2 ft

Iosco County · Clarity: 5.5 ft

Chippewa County · Clarity: 1.3 ft

Cass County · Clarity: 6 ft

Eutrophic Lakes in Wisconsin

Kimball Lake Van Etten Lake North Central Basin; Oscoda Township Community College Pond Pentwater Lake Northwest Basin; Pentwater Township

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