Eutrophic Lakes in Ohio

12 eutrophic lakes in Ohio. High nutrients, frequent algae, reduced clarity.

Eutrophic lakes — TSI 50 to 70 — are nutrient-rich and productive, with persistent summer algal communities that drive visible reductions in clarity. These conditions are not failures; they reflect a lake doing what nutrient-loaded waters do. 12 Ohio lakes register as eutrophic. Only 0% are deep — eutrophy correlates with shallowness, agricultural watersheds, and the kind of nutrient-input history that takes decades to shift.

Eutrophic lakes typically grade C or D on the LakeGrade rubric. The same nutrient richness that defines the trophic class drives the lower grade.

#	Lake	County	Grade	Clarity	Depth	TSI
1	Powers Reservoir	Crawford	B	-	-	56
2	Lost Creek Reservoir	Allen	B	-	-	51
3	Fremont Reservoir	Sandusky	C	-	-	57
4	Ferguson Reservoir	Allen	C	-	-	65
5	Williams Reservoir	Allen	C	-	-	59
6	Caesar Creek Lake	Warren	D	3.2 ft	-	57
7	Upper Sandusky Reservoir	Wyandot	D	-	-	63
8	Burr Oak Reservoir	Morgan	D	-	-	59
9	Lake Logan	Hocking	D	-	-	61
10	Metzger Reservoir	Allen	D	-	-	62
11	Twin Lakes Reservoir	Allen	D	-	-	68
12	Ottawa Reservoir	Putnam	D	-	-	66

All eutrophic lakes →Minnesota version →Wisconsin version →Illinois version →Michigan version →Iowa version →Pennsylvania version →New York version →Missouri version →Indiana version →North Dakota version →South Dakota version →Florida version →Colorado version →North Carolina version →Vermont version →Texas version →Oregon version →Arkansas version →Oklahoma version →Kansas version →Nebraska version →Nevada version →Arizona version →Idaho version →Montana version →New Mexico version →Tennessee version →Alabama version →Virginia version →Kentucky version →Utah version →Washington version →Wyoming version →Georgia version →Massachusetts version →Ontario version →Québec version →All Ohio lakes →

Source: EPA National Aquatic Resource Surveys, 2026.