Late afternoon sun over Slim Lake, scattering a bright path across wind-textured water

Washtenaw County Lake Quality

Michigan, 52 lakes, average grade A (Excellent)

Washtenaw County in Michigan carries 52 monitored lakes — one of the lake-richer counties in our dataset. Coverage that dense usually reflects active lake-association sampling alongside state-agency monitoring. 5 of those lakes carry an A–F grade. The county-level summary describes that subset, not every water body listed. On average, Washtenaw County lakes grade an A. That puts it near the top of the Michigan county ranking.

The county's lakes lean shallow, which makes the grades sensitive to wind, sediment-resuspension, and any nutrient inputs from the watershed. The cleanest lake on the books is Glacier Lake (A); the most-stressed is Little Portage Lake (B).

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Where to stay near Washtenaw County

Top-rated places to stay near Washtenaw County

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Quick Answers for Washtenaw County

Cleanest lakes in Washtenaw County →Cleanest lakes in Michigan →Safest swimming lakes in Michigan →

Planning a trip? Check special fishing regulations for Glacier Lake, whether the fish are safe to eat, and the best times to fish — or check the official Michigan fishing regulations.

Fishing in Washtenaw County

Washtenaw County Fishing Guide

Fish species and best-graded lakes in Washtenaw County

All Lakes in Washtenaw County

52 lakes · 5 graded, 47 not rated5 graded lakes · 47 not rated, hidden

Include not-rated lakes (47)

#	Lake	Grade	Clarity	Phosphorus	Algae	Trophic	Max Depth	Access
1	AGlacier LakeWashtenaw	A	6 ft	13.5 µg/L	2.2 µg/L	No recent samples	No recent samples	Not recorded
2	ANorth LakeWashtenaw	A	12.5 ft	13 µg/L	3.7 µg/L	No recent samples	58 ft	✓ Public
3	ACrystal LakeWashtenaw	A	12.5 ft	8.5 µg/L	1.6 µg/L	No recent samples	No recent samples	Not recorded
4	ASugarloaf LakeWashtenaw	A	9.5 ft	10 µg/L	1.9 µg/L	No recent samples	10 ft	✓ Public
5	BLittle Portage LakeWashtenaw	B	11 ft	14.5 µg/L	No recent samples	No recent samples	No recent samples	Not recorded
	NRPleasant LakeWashtenaw	NR	7.5 ft	No recent samples	No recent samples	No recent samples	36 ft	Not recorded
	NRBase Line LakeWashtenaw	NR	11 ft	No recent samples	No recent samples	No recent samples	No recent samples	Not recorded
	NRBruin LakeWashtenaw	NR	11.5 ft	No recent samples	No recent samples	No recent samples	48 ft	✓ Public
	NRSilver LakeWashtenaw	NR	11.5 ft	No recent samples	No recent samples	No recent samples	No recent samples	✓ Public
	NRFirst Sister LakeWashtenaw	NR	No recent samples	No recent samples	No recent samples	No recent samples	No recent samples	Not recorded
	NRSecond Sister LakeWashtenaw	NR	No recent samples	No recent samples	No recent samples	No recent samples	No recent samples	Not recorded
	NRFord LakeWashtenaw	NR	3 ft	36 µg/L	No recent samples	No recent samples	30 ft	Not recorded
	NRLong LakeWashtenaw	NR	9 ft	No recent samples	No recent samples	No recent samples	No recent samples	✓ Public
	NRPortage LakeWashtenaw	NR	No recent samples	No recent samples	No recent samples	No recent samples	84 ft	Not recorded
	NREllsworth LakeWashtenaw	NR	No recent samples	No recent samples	No recent samples	No recent samples	21 ft	Not recorded
	NRHalfmoon LakeWashtenaw	NR	No recent samples	No recent samples	No recent samples	No recent samples	80 ft	✓ Public
	NRJoslin LakeWashtenaw	NR	No recent samples	No recent samples	No recent samples	No recent samples	20 ft	✓ Public
	NRCrooked LakeWashtenaw	NR	No recent samples	No recent samples	No recent samples	No recent samples	30 ft	✓ Public
	NRWildwood LakeWashtenaw	NR	No recent samples	No recent samples	No recent samples	No recent samples	30 ft	Not recorded
	NRBlind LakeWashtenaw	NR	No recent samples	No recent samples	No recent samples	No recent samples	44 ft	Not recorded
	NRIndependence LakeWashtenaw	NR	No recent samples	No recent samples	No recent samples	No recent samples	30 ft	✓ Public
	NRSouth LakeWashtenaw	NR	No recent samples	No recent samples	No recent samples	No recent samples	80 ft	✓ Public
	NRHorseshoe LakeWashtenaw	NR	No recent samples	No recent samples	No recent samples	No recent samples	35 ft	Not recorded
	NRIsland LakeWashtenaw	NR	No recent samples	No recent samples	No recent samples	No recent samples	39 ft	Not recorded
	NRGreen LakeWashtenaw	NR	No recent samples	No recent samples	No recent samples	No recent samples	10 ft	✓ Public
	NRWest LakeWashtenaw	NR	No recent samples	No recent samples	No recent samples	No recent samples	26 ft	Not recorded
	NRWinnewana LakeWashtenaw	NR	No recent samples	No recent samples	No recent samples	No recent samples	8 ft	✓ Public
	NRFourmile LakeWashtenaw	NR	No recent samples	No recent samples	No recent samples	No recent samples	15 ft	✓ Public
	NRMill LakeWashtenaw	NR	No recent samples	No recent samples	No recent samples	No recent samples	25 ft	✓ Public
	NRCrooked LakeWashtenaw	NR	No recent samples	No recent samples	No recent samples	No recent samples	20 ft	✓ Public
	NRCavanaugh LakeWashtenaw	NR	No recent samples	No recent samples	No recent samples	No recent samples	50 ft	Not recorded
	NRBarton PondWashtenaw	NR	No recent samples	No recent samples	No recent samples	No recent samples	52 ft	Not recorded
	NRCedar LakeWashtenaw	NR	No recent samples	No recent samples	No recent samples	No recent samples	25 ft	✓ Public
	NRArgo PondWashtenaw	NR	No recent samples	No recent samples	No recent samples	No recent samples	No recent samples	Not recorded
	NRGeddes PondWashtenaw	NR	No recent samples	No recent samples	No recent samples	No recent samples	23 ft	✓ Public
	NRSutton LakeWashtenaw	NR	No recent samples	No recent samples	No recent samples	No recent samples	32 ft	Not recorded
	NRColumbia LakeWashtenaw	NR	No recent samples	No recent samples	No recent samples	No recent samples	27 ft	Not recorded
	NRIron Mill PondWashtenaw	NR	No recent samples	No recent samples	No recent samples	No recent samples	33 ft	Not recorded
	NRTwin LakesWashtenaw	NR	No recent samples	No recent samples	No recent samples	No recent samples	31 ft	Not recorded
	NRTobin LakeWashtenaw	NR	No recent samples	No recent samples	No recent samples	No recent samples	No recent samples	Not recorded
	NRParks LakeWashtenaw	NR	No recent samples	No recent samples	No recent samples	No recent samples	No recent samples	Not recorded
	NRArnold LakeWashtenaw	NR	No recent samples	No recent samples	No recent samples	No recent samples	No recent samples	Not recorded
	NRPierce LakeWashtenaw	NR	No recent samples	No recent samples	No recent samples	No recent samples	No recent samples	Not recorded
	NRGorman LakeWashtenaw	NR	No recent samples	No recent samples	No recent samples	No recent samples	No recent samples	Not recorded
	NRRiker LakeWashtenaw	NR	No recent samples	No recent samples	No recent samples	No recent samples	No recent samples	Not recorded
	NREllsworth LakeWashtenaw	NR	No recent samples	No recent samples	No recent samples	No recent samples	No recent samples	Not recorded
	NRCassidy LakeWashtenaw	NR	No recent samples	No recent samples	No recent samples	No recent samples	No recent samples	Not recorded
	NRMud LakeWashtenaw	NR	No recent samples	No recent samples	No recent samples	No recent samples	No recent samples	✓ Public
	NRLehman LakeWashtenaw	NR	No recent samples	No recent samples	No recent samples	No recent samples	No recent samples	Not recorded
	NRLower LakeWashtenaw	NR	No recent samples	No recent samples	No recent samples	No recent samples	No recent samples	Not recorded
	NRTwin LakesWashtenaw	NR	No recent samples	No recent samples	No recent samples	No recent samples	No recent samples	Not recorded
	NRJoslin LakeWashtenaw	NR	No recent samples	No recent samples	No recent samples	No recent samples	No recent samples	Not recorded

NR = not rated: there is not enough recent sampling to support a letter. That is EPA Integrated Reporting Category 3 (insufficient information), not a failing grade. How grading works.

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Other Counties in Michigan

Dickinson County

43 lakes · Avg grade A

Clare County

47 lakes · Avg grade A

Ogemaw County

50 lakes · Avg grade A

Cheboygan County

31 lakes · Avg grade A

Roscommon County

26 lakes · Avg grade A

Gladwin County

29 lakes · Avg grade A

See how Washtenaw County stacks up in the national county water-quality rankings, or browse the full directory of graded lakes across all United States (49 states), Canada (Ontario, Québec, Nova Scotia, British Columbia and Newfoundland and Labrador), and 38 other country hubs..

Source: EPA National Aquatic Resource Surveys, 2026.